diff options
Diffstat (limited to 'generic/tclIORTrans.c')
| -rw-r--r-- | generic/tclIORTrans.c | 3404 |
1 files changed, 3404 insertions, 0 deletions
diff --git a/generic/tclIORTrans.c b/generic/tclIORTrans.c new file mode 100644 index 0000000..fd645f7 --- /dev/null +++ b/generic/tclIORTrans.c @@ -0,0 +1,3404 @@ +/* + * tclIORTrans.c -- + * + * This file contains the implementation of Tcl's generic transformation + * reflection code, which allows the implementation of Tcl channel + * transformations in Tcl code. + * + * Parts of this file are based on code contributed by Jean-Claude + * Wippler. + * + * See TIP #230 for the specification of this functionality. + * + * Copyright (c) 2007-2008 ActiveState. + * + * See the file "license.terms" for information on usage and redistribution of + * this file, and for a DISCLAIMER OF ALL WARRANTIES. + */ + +#include "tclInt.h" +#include "tclIO.h" +#include <assert.h> + +#ifndef EINVAL +#define EINVAL 9 +#endif +#ifndef EOK +#define EOK 0 +#endif + +/* DUPLICATE of HaveVersion() in tclIO.c // TODO - MODULE_SCOPE */ +static int HaveVersion(const Tcl_ChannelType *typePtr, + Tcl_ChannelTypeVersion minimumVersion); + +/* + * Signatures of all functions used in the C layer of the reflection. + */ + +static int ReflectClose(ClientData clientData, + Tcl_Interp *interp); +static int ReflectInput(ClientData clientData, char *buf, + int toRead, int *errorCodePtr); +static int ReflectOutput(ClientData clientData, const char *buf, + int toWrite, int *errorCodePtr); +static void ReflectWatch(ClientData clientData, int mask); +static int ReflectBlock(ClientData clientData, int mode); +static Tcl_WideInt ReflectSeekWide(ClientData clientData, + Tcl_WideInt offset, int mode, int *errorCodePtr); +static int ReflectSeek(ClientData clientData, long offset, + int mode, int *errorCodePtr); +static int ReflectGetOption(ClientData clientData, + Tcl_Interp *interp, const char *optionName, + Tcl_DString *dsPtr); +static int ReflectSetOption(ClientData clientData, + Tcl_Interp *interp, const char *optionName, + const char *newValue); +static int ReflectHandle(ClientData clientData, int direction, + ClientData *handle); +static int ReflectNotify(ClientData clientData, int mask); + +/* + * The C layer channel type/driver definition used by the reflection. + */ + +static const Tcl_ChannelType tclRTransformType = { + "tclrtransform", /* Type name. */ + TCL_CHANNEL_VERSION_5, /* v5 channel. */ + ReflectClose, /* Close channel, clean instance data. */ + ReflectInput, /* Handle read request. */ + ReflectOutput, /* Handle write request. */ + ReflectSeek, /* Move location of access point. */ + ReflectSetOption, /* Set options. */ + ReflectGetOption, /* Get options. */ + ReflectWatch, /* Initialize notifier. */ + ReflectHandle, /* Get OS handle from the channel. */ + NULL, /* No close2 support. NULL'able. */ + ReflectBlock, /* Set blocking/nonblocking. */ + NULL, /* Flush channel. Not used by core. + * NULL'able. */ + ReflectNotify, /* Handle events. */ + ReflectSeekWide, /* Move access point (64 bit). */ + NULL, /* thread action */ + NULL /* truncate */ +}; + +/* + * Structure of the buffer to hold transform results to be consumed by higher + * layers upon reading from the channel, plus the functions to manage such. + */ + +typedef struct _ResultBuffer_ { + unsigned char *buf; /* Reference to the buffer area. */ + int allocated; /* Allocated size of the buffer area. */ + int used; /* Number of bytes in the buffer, + * <= allocated. */ +} ResultBuffer; + +#define ResultLength(r) ((r)->used) +/* static int ResultLength(ResultBuffer *r); */ + +static void ResultClear(ResultBuffer *r); +static void ResultInit(ResultBuffer *r); +static void ResultAdd(ResultBuffer *r, unsigned char *buf, + int toWrite); +static int ResultCopy(ResultBuffer *r, unsigned char *buf, + int toRead); + +#define RB_INCREMENT (512) + +/* + * Convenience macro to make some casts easier to use. + */ + +#define UCHARP(x) ((unsigned char *) (x)) + +/* + * Instance data for a reflected transformation. =========================== + */ + +typedef struct { + Tcl_Channel chan; /* Back reference to the channel of the + * transformation itself. */ + Tcl_Channel parent; /* Reference to the channel the transformation + * was pushed on. */ + Tcl_Interp *interp; /* Reference to the interpreter containing the + * Tcl level part of the channel. */ + Tcl_Obj *handle; /* Reference to transform handle. Also stored + * in the argv, see below. The separate field + * gives us direct access, needed when working + * with the reflection maps. */ +#ifdef TCL_THREADS + Tcl_ThreadId thread; /* Thread the 'interp' belongs to. */ +#endif + + Tcl_TimerToken timer; + + /* See [==] as well. + * Storage for the command prefix and the additional words required for + * the invocation of methods in the command handler. + * + * argv [0] ... [.] | [argc-2] [argc-1] | [argc] [argc+2] + * cmd ... pfx | method chan | detail1 detail2 + * ~~~~ CT ~~~ ~~ CT ~~ + * + * CT = Belongs to the 'Command handler Thread'. + */ + + int argc; /* Number of preallocated words - 2. */ + Tcl_Obj **argv; /* Preallocated array for calling the handler. + * args[0] is placeholder for cmd word. + * Followed by the arguments in the prefix, + * plus 4 placeholders for method, channel, + * and at most two varying (method specific) + * words. */ + int methods; /* Bitmask of supported methods. */ + + /* + * NOTE (9): Should we have predefined shared literals for the method + * names? + */ + + int mode; /* Mask of R/W mode */ + int nonblocking; /* Flag: Channel is blocking or not. */ + int readIsDrained; /* Flag: Read buffers are flushed. */ + ResultBuffer result; +} ReflectedTransform; + +/* + * Structure of the table mapping from transform handles to reflected + * transform (channels). Each interpreter which has the handler command for + * one or more reflected transforms records them in such a table, so that we + * are able to find them during interpreter/thread cleanup even if the actual + * channel they belong to was moved to a different interpreter and/or thread. + * + * The table is reachable via the standard interpreter AssocData, the key is + * defined below. + */ + +typedef struct { + Tcl_HashTable map; +} ReflectedTransformMap; + +#define RTMKEY "ReflectedTransformMap" + +/* + * Method literals. ================================================== + */ + +static const char *const methodNames[] = { + "clear", /* OPT */ + "drain", /* OPT, drain => read */ + "finalize", /* */ + "flush", /* OPT, flush => write */ + "initialize", /* */ + "limit?", /* OPT */ + "read", /* OPT */ + "write", /* OPT */ + NULL +}; +typedef enum { + METH_CLEAR, + METH_DRAIN, + METH_FINAL, + METH_FLUSH, + METH_INIT, + METH_LIMIT, + METH_READ, + METH_WRITE +} MethodName; + +#define FLAG(m) (1 << (m)) +#define REQUIRED_METHODS \ + (FLAG(METH_INIT) | FLAG(METH_FINAL)) +#define RANDW \ + (TCL_READABLE | TCL_WRITABLE) + +#define IMPLIES(a,b) ((!(a)) || (b)) +#define NEGIMPL(a,b) +#define HAS(x,f) (x & FLAG(f)) + +#ifdef TCL_THREADS +/* + * Thread specific types and structures. + * + * We are here essentially creating a very specific implementation of 'thread + * send'. + */ + +/* + * Enumeration of all operations which can be forwarded. + */ + +typedef enum { + ForwardedClear, + ForwardedClose, + ForwardedDrain, + ForwardedFlush, + ForwardedInput, + ForwardedLimit, + ForwardedOutput +} ForwardedOperation; + +/* + * Event used to forward driver invocations to the thread actually managing + * the channel. We cannot construct the command to execute and forward that. + * Because then it will contain a mixture of Tcl_Obj's belonging to both the + * command handler thread (CT), and the thread managing the channel (MT), + * executed in CT. Tcl_Obj's are not allowed to cross thread boundaries. So we + * forward an operation code, the argument details, and reference to results. + * The command is assembled in the CT and belongs fully to that thread. No + * sharing problems. + */ + +typedef struct ForwardParamBase { + int code; /* O: Ok/Fail of the cmd handler */ + char *msgStr; /* O: Error message for handler failure */ + int mustFree; /* O: True if msgStr is allocated, false if + * otherwise (static). */ +} ForwardParamBase; + +/* + * Operation specific parameter/result structures. (These are "subtypes" of + * ForwardParamBase. Where an operation does not need any special types, it + * has no "subtype" and just uses ForwardParamBase, as listed above.) + */ + +struct ForwardParamTransform { + ForwardParamBase base; /* "Supertype". MUST COME FIRST. */ + char *buf; /* I: Bytes to transform, + * O: Bytes in transform result */ + int size; /* I: #bytes to transform, + * O: #bytes in the transform result */ +}; +struct ForwardParamLimit { + ForwardParamBase base; /* "Supertype". MUST COME FIRST. */ + int max; /* O: Character read limit */ +}; + +/* + * Now join all these together in a single union for convenience. + */ + +typedef union ForwardParam { + ForwardParamBase base; + struct ForwardParamTransform transform; + struct ForwardParamLimit limit; +} ForwardParam; + +/* + * Forward declaration. + */ + +typedef struct ForwardingResult ForwardingResult; + +/* + * General event structure, with reference to operation specific data. + */ + +typedef struct ForwardingEvent { + Tcl_Event event; /* Basic event data, has to be first item */ + ForwardingResult *resultPtr; + ForwardedOperation op; /* Forwarded driver operation */ + ReflectedTransform *rtPtr; /* Channel instance */ + ForwardParam *param; /* Packaged arguments and return values, a + * ForwardParam pointer. */ +} ForwardingEvent; + +/* + * Structure to manage the result of the forwarding. This is not the result of + * the operation itself, but about the success of the forward event itself. + * The event can be successful, even if the operation which was forwarded + * failed. It is also there to manage the synchronization between the involved + * threads. + */ + +struct ForwardingResult { + Tcl_ThreadId src; /* Originating thread. */ + Tcl_ThreadId dst; /* Thread the op was forwarded to. */ + Tcl_Interp *dsti; /* Interpreter in the thread the op was + * forwarded to. */ + Tcl_Condition done; /* Condition variable the forwarder blocks + * on. */ + int result; /* TCL_OK or TCL_ERROR */ + ForwardingEvent *evPtr; /* Event the result belongs to. */ + ForwardingResult *prevPtr, *nextPtr; + /* Links into the list of pending forwarded + * results. */ +}; + +typedef struct ThreadSpecificData { + /* + * Table of all reflected transformations owned by this thread. + */ + + ReflectedTransformMap *rtmPtr; +} ThreadSpecificData; + +static Tcl_ThreadDataKey dataKey; + +/* + * List of forwarded operations which have not completed yet, plus the mutex + * to protect the access to this process global list. + */ + +static ForwardingResult *forwardList = NULL; +TCL_DECLARE_MUTEX(rtForwardMutex) + +/* + * Function containing the generic code executing a forward, and wrapper + * macros for the actual operations we wish to forward. Uses ForwardProc as + * the event function executed by the thread receiving a forwarding event + * (which executes the appropriate function and collects the result, if any). + * + * The two ExitProcs are handlers so that things do not deadlock when either + * thread involved in the forwarding exits. They also clean things up so that + * we don't leak resources when threads go away. + */ + +static void ForwardOpToOwnerThread(ReflectedTransform *rtPtr, + ForwardedOperation op, const void *param); +static int ForwardProc(Tcl_Event *evPtr, int mask); +static void SrcExitProc(ClientData clientData); + +#define FreeReceivedError(p) \ + if ((p)->base.mustFree) { \ + ckfree((p)->base.msgStr); \ + } +#define PassReceivedErrorInterp(i,p) \ + if ((i) != NULL) { \ + Tcl_SetChannelErrorInterp((i), \ + Tcl_NewStringObj((p)->base.msgStr, -1)); \ + } \ + FreeReceivedError(p) +#define PassReceivedError(c,p) \ + Tcl_SetChannelError((c), Tcl_NewStringObj((p)->base.msgStr, -1)); \ + FreeReceivedError(p) +#define ForwardSetStaticError(p,emsg) \ + (p)->base.code = TCL_ERROR; \ + (p)->base.mustFree = 0; \ + (p)->base.msgStr = (char *) (emsg) +#define ForwardSetDynamicError(p,emsg) \ + (p)->base.code = TCL_ERROR; \ + (p)->base.mustFree = 1; \ + (p)->base.msgStr = (char *) (emsg) + +static void ForwardSetObjError(ForwardParam *p, + Tcl_Obj *objPtr); + +static ReflectedTransformMap * GetThreadReflectedTransformMap(void); +static void DeleteThreadReflectedTransformMap(ClientData clientData); + +#endif /* TCL_THREADS */ + +#define SetChannelErrorStr(c,msgStr) \ + Tcl_SetChannelError((c), Tcl_NewStringObj((msgStr), -1)) + +static Tcl_Obj * MarshallError(Tcl_Interp *interp); +static void UnmarshallErrorResult(Tcl_Interp *interp, + Tcl_Obj *msgObj); + +/* + * Static functions for this file: + */ + +static Tcl_Obj * DecodeEventMask(int mask); +static ReflectedTransform * NewReflectedTransform(Tcl_Interp *interp, + Tcl_Obj *cmdpfxObj, int mode, Tcl_Obj *handleObj, + Tcl_Channel parentChan); +static Tcl_Obj * NextHandle(void); +static void FreeReflectedTransform(ReflectedTransform *rtPtr); +static int InvokeTclMethod(ReflectedTransform *rtPtr, + const char *method, Tcl_Obj *argOneObj, + Tcl_Obj *argTwoObj, Tcl_Obj **resultObjPtr); + +static ReflectedTransformMap * GetReflectedTransformMap(Tcl_Interp *interp); +static void DeleteReflectedTransformMap(ClientData clientData, + Tcl_Interp *interp); + +/* + * Global constant strings (messages). ================== + * These string are used directly as bypass errors, thus they have to be valid + * Tcl lists where the last element is the message itself. Hence the + * list-quoting to keep the words of the message together. See also [x]. + */ + +static const char *msg_read_unsup = "{read not supported by Tcl driver}"; +static const char *msg_write_unsup = "{write not supported by Tcl driver}"; +#ifdef TCL_THREADS +static const char *msg_send_originlost = "{Channel thread lost}"; +static const char *msg_send_dstlost = "{Owner lost}"; +#endif /* TCL_THREADS */ +static const char *msg_dstlost = + "-code 1 -level 0 -errorcode NONE -errorinfo {} -errorline 1 {Owner lost}"; + +/* + * Timer management (flushing out buffered data via artificial events). + */ + +/* + * Number of milliseconds to wait before firing an event to try to flush out + * information waiting in buffers (fileevent support). + */ + +#define FLUSH_DELAY (5) + +/* + * Helper functions encapsulating some of the thread forwarding to make the + * control flow in callers easier. + */ + +static void TimerKill(ReflectedTransform *rtPtr); +static void TimerSetup(ReflectedTransform *rtPtr); +static void TimerRun(ClientData clientData); +static int TransformRead(ReflectedTransform *rtPtr, + int *errorCodePtr, unsigned char *buf, + int toRead); +static int TransformWrite(ReflectedTransform *rtPtr, + int *errorCodePtr, unsigned char *buf, + int toWrite); +static int TransformDrain(ReflectedTransform *rtPtr, + int *errorCodePtr); +static int TransformFlush(ReflectedTransform *rtPtr, + int *errorCodePtr, int op); +static void TransformClear(ReflectedTransform *rtPtr); +static int TransformLimit(ReflectedTransform *rtPtr, + int *errorCodePtr, int *maxPtr); + +/* + * Operation codes for TransformFlush(). + */ + +#define FLUSH_WRITE 1 +#define FLUSH_DISCARD 0 + +/* + * Main methods to plug into the 'chan' ensemble'. ================== + */ + +/* + *---------------------------------------------------------------------- + * + * TclChanPushObjCmd -- + * + * This function is invoked to process the "chan push" Tcl command. See + * the user documentation for details on what it does. + * + * Results: + * A standard Tcl result. The handle of the new channel is placed in the + * interp result. + * + * Side effects: + * Creates a new channel. + * + *---------------------------------------------------------------------- + */ + +int +TclChanPushObjCmd( + ClientData clientData, + Tcl_Interp *interp, + int objc, + Tcl_Obj *const *objv) +{ + ReflectedTransform *rtPtr; /* Instance data of the new (transform) + * channel. */ + Tcl_Obj *chanObj; /* Handle of parent channel */ + Tcl_Channel parentChan; /* Token of parent channel */ + int mode; /* R/W mode of parent, later the new channel. + * Has to match the abilities of the handler + * commands */ + Tcl_Obj *cmdObj; /* Command prefix, list of words */ + Tcl_Obj *cmdNameObj; /* Command name */ + Tcl_Obj *rtId; /* Handle of the new transform (channel) */ + Tcl_Obj *modeObj; /* mode in obj form for method call */ + int listc; /* Result of 'initialize', and of */ + Tcl_Obj **listv; /* its sublist in the 2nd element */ + int methIndex; /* Encoded method name */ + int result; /* Result code for 'initialize' */ + Tcl_Obj *resObj; /* Result data for 'initialize' */ + int methods; /* Bitmask for supported methods. */ + Tcl_Obj *err; /* Error message */ + ReflectedTransformMap *rtmPtr; + /* Map of reflected transforms with handlers + * in this interp. */ + Tcl_HashEntry *hPtr; /* Entry in the above map */ + int isNew; /* Placeholder. */ + + /* + * Syntax: chan push CHANNEL CMDPREFIX + * [0] [1] [2] [3] + * + * Actually: rPush CHANNEL CMDPREFIX + * [0] [1] [2] + */ + +#define CHAN (1) +#define CMD (2) + + /* + * Number of arguments... + */ + + if (objc != 3) { + Tcl_WrongNumArgs(interp, 1, objv, "channel cmdprefix"); + return TCL_ERROR; + } + + /* + * First argument is a channel handle. + */ + + chanObj = objv[CHAN]; + parentChan = Tcl_GetChannel(interp, Tcl_GetString(chanObj), &mode); + if (parentChan == NULL) { + return TCL_ERROR; + } + parentChan = Tcl_GetTopChannel(parentChan); + + /* + * Second argument is command prefix, i.e. list of words, first word is + * name of handler command, other words are fixed arguments. Run the + * 'initialize' method to get the list of supported methods. Validate + * this. + */ + + cmdObj = objv[CMD]; + + /* + * Basic check that the command prefix truly is a list. + */ + + if (Tcl_ListObjIndex(interp, cmdObj, 0, &cmdNameObj) != TCL_OK) { + return TCL_ERROR; + } + + /* + * Now create the transformation (channel). + */ + + rtId = NextHandle(); + rtPtr = NewReflectedTransform(interp, cmdObj, mode, rtId, parentChan); + + /* + * Invoke 'initialize' and validate that the handler is present and ok. + * Squash the transformation if not. + */ + + modeObj = DecodeEventMask(mode); + /* assert modeObj.refCount == 1 */ + result = InvokeTclMethod(rtPtr, "initialize", modeObj, NULL, &resObj); + Tcl_DecrRefCount(modeObj); + if (result != TCL_OK) { + UnmarshallErrorResult(interp, resObj); + Tcl_DecrRefCount(resObj); /* Remove reference held from invoke */ + goto error; + } + + /* + * Verify the result. + * - List, of method names. Convert to mask. Check for non-optionals + * through the mask. Compare open mode against optional r/w. + */ + + if (Tcl_ListObjGetElements(NULL, resObj, &listc, &listv) != TCL_OK) { + TclNewLiteralStringObj(err, "chan handler \""); + Tcl_AppendObjToObj(err, cmdObj); + Tcl_AppendToObj(err, " initialize\" returned non-list: ", -1); + Tcl_AppendObjToObj(err, resObj); + Tcl_SetObjResult(interp, err); + Tcl_DecrRefCount(resObj); + goto error; + } + + methods = 0; + while (listc > 0) { + if (Tcl_GetIndexFromObj(interp, listv[listc-1], methodNames, + "method", TCL_EXACT, &methIndex) != TCL_OK) { + TclNewLiteralStringObj(err, "chan handler \""); + Tcl_AppendObjToObj(err, cmdObj); + Tcl_AppendToObj(err, " initialize\" returned ", -1); + Tcl_AppendObjToObj(err, Tcl_GetObjResult(interp)); + Tcl_SetObjResult(interp, err); + Tcl_DecrRefCount(resObj); + goto error; + } + + methods |= FLAG(methIndex); + listc--; + } + Tcl_DecrRefCount(resObj); + + if ((REQUIRED_METHODS & methods) != REQUIRED_METHODS) { + TclNewLiteralStringObj(err, "chan handler \""); + Tcl_AppendObjToObj(err, cmdObj); + Tcl_AppendToObj(err, "\" does not support all required methods", -1); + Tcl_SetObjResult(interp, err); + goto error; + } + + /* + * Mode tell us what the parent channel supports. The methods tell us what + * the handler supports. We remove the non-supported bits from the mode + * and check that the channel is not completely inacessible. Afterward the + * mode tells us which methods are still required, and these methods will + * also be supported by the handler, by design of the check. + */ + + if (!HAS(methods, METH_READ)) { + mode &= ~TCL_READABLE; + } + if (!HAS(methods, METH_WRITE)) { + mode &= ~TCL_WRITABLE; + } + + if (!mode) { + TclNewLiteralStringObj(err, "chan handler \""); + Tcl_AppendObjToObj(err, cmdObj); + Tcl_AppendToObj(err, "\" makes the channel inacessible", -1); + Tcl_SetObjResult(interp, err); + goto error; + } + + /* + * The mode and support for it is ok, now check the internal constraints. + */ + + if (!IMPLIES(HAS(methods, METH_DRAIN), HAS(methods, METH_READ))) { + TclNewLiteralStringObj(err, "chan handler \""); + Tcl_AppendObjToObj(err, cmdObj); + Tcl_AppendToObj(err, "\" supports \"drain\" but not \"read\"", -1); + Tcl_SetObjResult(interp, err); + goto error; + } + + if (!IMPLIES(HAS(methods, METH_FLUSH), HAS(methods, METH_WRITE))) { + TclNewLiteralStringObj(err, "chan handler \""); + Tcl_AppendObjToObj(err, cmdObj); + Tcl_AppendToObj(err, "\" supports \"flush\" but not \"write\"", -1); + Tcl_SetObjResult(interp, err); + goto error; + } + + Tcl_ResetResult(interp); + + /* + * Everything is fine now. + */ + + rtPtr->methods = methods; + rtPtr->mode = mode; + rtPtr->chan = Tcl_StackChannel(interp, &tclRTransformType, rtPtr, mode, + rtPtr->parent); + + /* + * Register the transform in our our map for proper handling of deleted + * interpreters and/or threads. + */ + + rtmPtr = GetReflectedTransformMap(interp); + hPtr = Tcl_CreateHashEntry(&rtmPtr->map, Tcl_GetString(rtId), &isNew); + if (!isNew && rtPtr != Tcl_GetHashValue(hPtr)) { + Tcl_Panic("TclChanPushObjCmd: duplicate transformation handle"); + } + Tcl_SetHashValue(hPtr, rtPtr); +#ifdef TCL_THREADS + rtmPtr = GetThreadReflectedTransformMap(); + hPtr = Tcl_CreateHashEntry(&rtmPtr->map, Tcl_GetString(rtId), &isNew); + Tcl_SetHashValue(hPtr, rtPtr); +#endif + + /* + * Return the channel as the result of the command. + */ + + Tcl_AppendResult(interp, Tcl_GetChannelName(rtPtr->chan), NULL); + return TCL_OK; + + error: + /* + * We are not going through ReflectClose as we never had a channel + * structure. + */ + + Tcl_EventuallyFree (rtPtr, (Tcl_FreeProc *) FreeReflectedTransform); + return TCL_ERROR; + +#undef CHAN +#undef CMD +} + +/* + *---------------------------------------------------------------------- + * + * TclChanPopObjCmd -- + * + * This function is invoked to process the "chan pop" Tcl command. See + * the user documentation for details on what it does. + * + * Results: + * A standard Tcl result. + * + * Side effects: + * Posts events to a reflected channel, invokes event handlers. The + * latter implies that arbitrary side effects are possible. + * + *---------------------------------------------------------------------- + */ + +int +TclChanPopObjCmd( + ClientData clientData, + Tcl_Interp *interp, + int objc, + Tcl_Obj *const *objv) +{ + /* + * Syntax: chan pop CHANNEL + * [0] [1] [2] + * + * Actually: rPop CHANNEL + * [0] [1] + */ + +#define CHAN (1) + + const char *chanId; /* Tcl level channel handle */ + Tcl_Channel chan; /* Channel associated to the handle */ + int mode; /* Channel r/w mode */ + + /* + * Number of arguments... + */ + + if (objc != 2) { + Tcl_WrongNumArgs(interp, 1, objv, "channel"); + return TCL_ERROR; + } + + /* + * First argument is a channel, which may have a (reflected) + * transformation. + */ + + chanId = TclGetString(objv[CHAN]); + chan = Tcl_GetChannel(interp, chanId, &mode); + + if (chan == NULL) { + return TCL_ERROR; + } + + /* + * Removing transformations is generic, and not restricted to reflected + * transformations. + */ + + Tcl_UnstackChannel(interp, chan); + return TCL_OK; + +#undef CHAN +} + +/* + * Channel error message marshalling utilities. + */ + +static Tcl_Obj * +MarshallError( + Tcl_Interp *interp) +{ + /* + * Capture the result status of the interpreter into a string. => List of + * options and values, followed by the error message. The result has + * refCount 0. + */ + + Tcl_Obj *returnOpt = Tcl_GetReturnOptions(interp, TCL_ERROR); + + /* + * => returnOpt.refCount == 0. We can append directly. + */ + + Tcl_ListObjAppendElement(NULL, returnOpt, Tcl_GetObjResult(interp)); + return returnOpt; +} + +static void +UnmarshallErrorResult( + Tcl_Interp *interp, + Tcl_Obj *msgObj) +{ + int lc; + Tcl_Obj **lv; + int explicitResult; + int numOptions; + + /* + * Process the caught message. + * + * Syntax = (option value)... ?message? + * + * Bad syntax causes a panic. This is OK because the other side uses + * Tcl_GetReturnOptions and list construction functions to marshall the + * information; if we panic here, something has gone badly wrong already. + */ + + if (Tcl_ListObjGetElements(interp, msgObj, &lc, &lv) != TCL_OK) { + Tcl_Panic("TclChanCaughtErrorBypass: Bad syntax of caught result"); + } + if (interp == NULL) { + return; + } + + explicitResult = lc & 1; /* Odd number of values? */ + numOptions = lc - explicitResult; + + if (explicitResult) { + Tcl_SetObjResult(interp, lv[lc-1]); + } + + Tcl_SetReturnOptions(interp, Tcl_NewListObj(numOptions, lv)); + ((Interp *) interp)->flags &= ~ERR_ALREADY_LOGGED; +} + +/* + * Driver functions. ================================================ + */ + +/* + *---------------------------------------------------------------------- + * + * ReflectClose -- + * + * This function is invoked when the channel is closed, to delete the + * driver specific instance data. + * + * Results: + * A posix error. + * + * Side effects: + * Releases memory. Arbitrary, as it calls upon a script. + * + *---------------------------------------------------------------------- + */ + +static int +ReflectClose( + ClientData clientData, + Tcl_Interp *interp) +{ + ReflectedTransform *rtPtr = clientData; + int result; /* Result code for 'close' */ + Tcl_Obj *resObj; /* Result data for 'close' */ + ReflectedTransformMap *rtmPtr; + /* Map of reflected transforms with handlers + * in this interp. */ + Tcl_HashEntry *hPtr; /* Entry in the above map */ + + if (TclInThreadExit()) { + /* + * This call comes from TclFinalizeIOSystem. There are no + * interpreters, and therefore we cannot call upon the handler command + * anymore. Threading is irrelevant as well. We simply clean up all + * our C level data structures and leave the Tcl level to the other + * finalization functions. + */ + + /* + * THREADED => Forward this to the origin thread + * + * Note: DeleteThreadReflectedTransformMap() is the thread exit handler + * for the origin thread. Use this to clean up the structure? Except + * if lost? + */ + +#ifdef TCL_THREADS + if (rtPtr->thread != Tcl_GetCurrentThread()) { + ForwardParam p; + + ForwardOpToOwnerThread(rtPtr, ForwardedClose, &p); + result = p.base.code; + + /* + * FreeReflectedTransform is done in the forwarded operation!, in + * the other thread. rtPtr here is gone! + */ + + if (result != TCL_OK) { + FreeReceivedError(&p); + } + return EOK; + } +#endif + + Tcl_EventuallyFree (rtPtr, (Tcl_FreeProc *) FreeReflectedTransform); + return EOK; + } + + /* + * In the reflected channel implementation a cleaned method mask here + * implies that the channel creation was aborted, and "finalize" must not + * be called. for transformations however we are not going through here on + * such an abort, but directly through FreeReflectedTransform. So for us + * that check is not necessary. We always go through 'finalize'. + */ + + if (HAS(rtPtr->methods, METH_DRAIN) && !rtPtr->readIsDrained) { + int errorCode; + + if (!TransformDrain(rtPtr, &errorCode)) { + return errorCode; + } + } + + if (HAS(rtPtr->methods, METH_FLUSH)) { + int errorCode; + + if (!TransformFlush(rtPtr, &errorCode, FLUSH_WRITE)) { + return errorCode; + } + } + + /* + * Are we in the correct thread? + */ + +#ifdef TCL_THREADS + if (rtPtr->thread != Tcl_GetCurrentThread()) { + ForwardParam p; + + ForwardOpToOwnerThread(rtPtr, ForwardedClose, &p); + result = p.base.code; + + /* + * FreeReflectedTransform is done in the forwarded operation!, in the + * other thread. rtPtr here is gone! + */ + + if (result != TCL_OK) { + PassReceivedErrorInterp(interp, &p); + return EINVAL; + } + return EOK; + } +#endif + + /* + * Do the actual invokation of "finalize" now; we're in the right thread. + */ + + result = InvokeTclMethod(rtPtr, "finalize", NULL, NULL, &resObj); + if ((result != TCL_OK) && (interp != NULL)) { + Tcl_SetChannelErrorInterp(interp, resObj); + } + + Tcl_DecrRefCount(resObj); /* Remove reference we held from the + * invoke. */ + + /* + * Remove the transform from the map before releasing the memory, to + * prevent future accesses from finding and dereferencing a dangling + * pointer. + * + * NOTE: The transform may not be in the map. This is ok, that happens + * when the transform was created in a different interpreter and/or thread + * and then was moved here. + * + * NOTE: The channel may have been removed from the map already via + * the per-interp DeleteReflectedTransformMap exit-handler. + */ + + if (rtPtr->interp) { + rtmPtr = GetReflectedTransformMap(rtPtr->interp); + hPtr = Tcl_FindHashEntry(&rtmPtr->map, Tcl_GetString(rtPtr->handle)); + if (hPtr) { + Tcl_DeleteHashEntry(hPtr); + } + } + + /* + * In a threaded interpreter we manage a per-thread map as well, to allow + * us to survive if the script level pulls the rug out under a channel by + * deleting the owning thread. + */ + +#ifdef TCL_THREADS + rtmPtr = GetThreadReflectedTransformMap(); + hPtr = Tcl_FindHashEntry(&rtmPtr->map, Tcl_GetString(rtPtr->handle)); + if (hPtr) { + Tcl_DeleteHashEntry(hPtr); + } +#endif + + Tcl_EventuallyFree (rtPtr, (Tcl_FreeProc *) FreeReflectedTransform); + return (result == TCL_OK) ? EOK : EINVAL; +} + +/* + *---------------------------------------------------------------------- + * + * ReflectInput -- + * + * This function is invoked when more data is requested from the channel. + * + * Results: + * The number of bytes read. + * + * Side effects: + * Allocates memory. Arbitrary, as it calls upon a script. + * + *---------------------------------------------------------------------- + */ + +static int +ReflectInput( + ClientData clientData, + char *buf, + int toRead, + int *errorCodePtr) +{ + ReflectedTransform *rtPtr = clientData; + int gotBytes, copied, readBytes; + + /* + * The following check can be done before thread redirection, because we + * are reading from an item which is readonly, i.e. will never change + * during the lifetime of the channel. + */ + + if (!(rtPtr->methods & FLAG(METH_READ))) { + SetChannelErrorStr(rtPtr->chan, msg_read_unsup); + *errorCodePtr = EINVAL; + return -1; + } + + Tcl_Preserve(rtPtr); + + gotBytes = 0; + while (toRead > 0) { + /* + * Loop until the request is satisfied (or no data available from + * below, possibly EOF). + */ + + copied = ResultCopy(&rtPtr->result, UCHARP(buf), toRead); + toRead -= copied; + buf += copied; + gotBytes += copied; + + if (toRead == 0) { + goto stop; + } + + /* + * The buffer is exhausted, but the caller wants even more. We now + * have to go to the underlying channel, get more bytes and then + * transform them for delivery. We may not get what we want (full EOF + * or temporarily out of data). + * + * Length (rtPtr->result) == 0, toRead > 0 here. Use 'buf'! as target + * to store the intermediary information read from the parent channel. + * + * Ask the transform how much data it allows us to read from the + * underlying channel. This feature allows the transform to signal EOF + * upstream although there is none downstream. Useful to control an + * unbounded 'fcopy' for example, either through counting bytes, or by + * pattern matching. + */ + + if ((rtPtr->methods & FLAG(METH_LIMIT))) { + int maxRead = -1; + + if (!TransformLimit(rtPtr, errorCodePtr, &maxRead)) { + goto error; + } + if (maxRead == 0) { + goto stop; + } else if (maxRead > 0) { + if (maxRead < toRead) { + toRead = maxRead; + } + } /* else: 'maxRead < 0' == Accept the current value of toRead */ + } + + if (toRead <= 0) { + goto stop; + } + + readBytes = Tcl_ReadRaw(rtPtr->parent, buf, toRead); + if (readBytes < 0) { + /* + * Report errors to caller. The state of the seek system is + * unchanged! + */ + + if ((Tcl_GetErrno() == EAGAIN) && (gotBytes > 0)) { + /* + * EAGAIN is a special situation. If we had some data before + * we report that instead of the request to re-try. + */ + + goto stop; + } + + *errorCodePtr = Tcl_GetErrno(); + goto error; + } + + if (readBytes == 0) { + /* + * Check wether we hit on EOF in 'parent' or not. If not + * differentiate between blocking and non-blocking modes. In + * non-blocking mode we ran temporarily out of data. Signal this + * to the caller via EWOULDBLOCK and error return (-1). In the + * other cases we simply return what we got and let the caller + * wait for more. On the other hand, if we got an EOF we have to + * convert and flush all waiting partial data. + */ + + if (!Tcl_Eof(rtPtr->parent)) { + /* + * The state of the seek system is unchanged! + */ + + if ((gotBytes == 0) && rtPtr->nonblocking) { + *errorCodePtr = EWOULDBLOCK; + goto error; + } + goto stop; + } else { + /* + * Eof in parent. + */ + + if (rtPtr->readIsDrained) { + goto stop; + } + + /* + * Now this is a bit different. The partial data waiting is + * converted and returned. + */ + + if (HAS(rtPtr->methods, METH_DRAIN)) { + if (!TransformDrain(rtPtr, errorCodePtr)) { + goto error; + } + } + + if (ResultLength(&rtPtr->result) == 0) { + /* + * The drain delivered nothing. + */ + + goto stop; + } + + /* + * Reset eof, force caller to drain result buffer. + */ + + ((Channel *) rtPtr->parent)->state->flags &= ~CHANNEL_EOF; + continue; /* at: while (toRead > 0) */ + } + } /* readBytes == 0 */ + + /* + * Transform the read chunk, which was not empty. Anything we got back + * is a transformation result is put into our buffers, and the next + * iteration will put it into the result. + */ + + if (!TransformRead(rtPtr, errorCodePtr, UCHARP(buf), readBytes)) { + goto error; + } + } /* while toRead > 0 */ + + stop: + Tcl_Release(rtPtr); + return gotBytes; + + error: + gotBytes = -1; + goto stop; +} + +/* + *---------------------------------------------------------------------- + * + * ReflectOutput -- + * + * This function is invoked when data is writen to the channel. + * + * Results: + * The number of bytes actually written. + * + * Side effects: + * Allocates memory. Arbitrary, as it calls upon a script. + * + *---------------------------------------------------------------------- + */ + +static int +ReflectOutput( + ClientData clientData, + const char *buf, + int toWrite, + int *errorCodePtr) +{ + ReflectedTransform *rtPtr = clientData; + + /* + * The following check can be done before thread redirection, because we + * are reading from an item which is readonly, i.e. will never change + * during the lifetime of the channel. + */ + + if (!(rtPtr->methods & FLAG(METH_WRITE))) { + SetChannelErrorStr(rtPtr->chan, msg_write_unsup); + *errorCodePtr = EINVAL; + return -1; + } + + if (toWrite == 0) { + /* + * Nothing came in to write, ignore the call + */ + + return 0; + } + + /* + * Discard partial data in the input buffers, i.e. on the read side. Like + * we do when explicitly seeking as well. + */ + + Tcl_Preserve(rtPtr); + + if ((rtPtr->methods & FLAG(METH_CLEAR))) { + TransformClear(rtPtr); + } + + /* + * Hand the data to the transformation itself. Anything it deigned to + * return to us is a (partial) transformation result and written to the + * parent channel for further processing. + */ + + if (!TransformWrite(rtPtr, errorCodePtr, UCHARP(buf), toWrite)) { + Tcl_Release(rtPtr); + return -1; + } + + *errorCodePtr = EOK; + Tcl_Release(rtPtr); + return toWrite; +} + +/* + *---------------------------------------------------------------------- + * + * ReflectSeekWide / ReflectSeek -- + * + * This function is invoked when the user wishes to seek on the channel. + * + * Results: + * The new location of the access point. + * + * Side effects: + * Allocates memory. Arbitrary, per the parent channel, and the called + * scripts. + * + *---------------------------------------------------------------------- + */ + +static Tcl_WideInt +ReflectSeekWide( + ClientData clientData, + Tcl_WideInt offset, + int seekMode, + int *errorCodePtr) +{ + ReflectedTransform *rtPtr = clientData; + Channel *parent = (Channel *) rtPtr->parent; + Tcl_WideInt curPos; /* Position on the device. */ + + Tcl_DriverSeekProc *seekProc = + Tcl_ChannelSeekProc(Tcl_GetChannelType(rtPtr->parent)); + + /* + * Fail if the parent channel is not seekable. + */ + + if (seekProc == NULL) { + Tcl_SetErrno(EINVAL); + return Tcl_LongAsWide(-1); + } + + /* + * Check if we can leave out involving the Tcl level, i.e. transformation + * handler. This is true for tell requests, and transformations which + * support neither flush, nor drain. For these cases we can pass the + * request down and the result back up unchanged. + */ + + Tcl_Preserve(rtPtr); + + if (((seekMode != SEEK_CUR) || (offset != 0)) + && (HAS(rtPtr->methods, METH_CLEAR) + || HAS(rtPtr->methods, METH_FLUSH))) { + /* + * Neither a tell request, nor clear/flush both not supported. We have + * to go through the Tcl level to clear and/or flush the + * transformation. + */ + + if ((rtPtr->methods & FLAG(METH_CLEAR))) { + TransformClear(rtPtr); + } + + /* + * When flushing the transform for seeking the generated results are + * irrelevant. We cannot put them into the channel, this would move + * the location, throwing it off with regard to where we are and are + * seeking to. + */ + + if (HAS(rtPtr->methods, METH_FLUSH)) { + if (!TransformFlush(rtPtr, errorCodePtr, FLUSH_DISCARD)) { + Tcl_Release(rtPtr); + return -1; + } + } + } + + /* + * Now seek to the new position in the channel as requested by the + * caller. Note that we prefer the wideSeekProc if that is available and + * non-NULL... + */ + + if (HaveVersion(parent->typePtr, TCL_CHANNEL_VERSION_3) && + parent->typePtr->wideSeekProc != NULL) { + curPos = parent->typePtr->wideSeekProc(parent->instanceData, offset, + seekMode, errorCodePtr); + } else if (offset < Tcl_LongAsWide(LONG_MIN) || + offset > Tcl_LongAsWide(LONG_MAX)) { + *errorCodePtr = EOVERFLOW; + curPos = Tcl_LongAsWide(-1); + } else { + curPos = Tcl_LongAsWide(parent->typePtr->seekProc( + parent->instanceData, Tcl_WideAsLong(offset), seekMode, + errorCodePtr)); + } + if (curPos == Tcl_LongAsWide(-1)) { + Tcl_SetErrno(*errorCodePtr); + } + + *errorCodePtr = EOK; + Tcl_Release(rtPtr); + return curPos; +} + +static int +ReflectSeek( + ClientData clientData, + long offset, + int seekMode, + int *errorCodePtr) +{ + /* + * This function can be invoked from a transformation which is based on + * standard seeking, i.e. non-wide. Because of this we have to implement + * it, a dummy is not enough. We simply delegate the call to the wide + * routine. + */ + + return (int) ReflectSeekWide(clientData, Tcl_LongAsWide(offset), seekMode, + errorCodePtr); +} + +/* + *---------------------------------------------------------------------- + * + * ReflectWatch -- + * + * This function is invoked to tell the channel what events the I/O + * system is interested in. + * + * Results: + * None. + * + * Side effects: + * Allocates memory. Arbitrary, as it calls upon a script. + * + *---------------------------------------------------------------------- + */ + +static void +ReflectWatch( + ClientData clientData, + int mask) +{ + ReflectedTransform *rtPtr = clientData; + Tcl_DriverWatchProc *watchProc; + + watchProc = Tcl_ChannelWatchProc(Tcl_GetChannelType(rtPtr->parent)); + watchProc(Tcl_GetChannelInstanceData(rtPtr->parent), mask); + + /* + * Management of the internal timer. + */ + + if (!(mask & TCL_READABLE) || (ResultLength(&rtPtr->result) == 0)) { + /* + * A pending timer may exist, but either is there no (more) interest + * in the events it generates or nothing is available for reading. + * Remove it, if existing. + */ + + TimerKill(rtPtr); + } else { + /* + * There might be no pending timer, but there is interest in readable + * events and we actually have data waiting, so generate a timer to + * flush that if it does not exist. + */ + + TimerSetup(rtPtr); + } +} + +/* + *---------------------------------------------------------------------- + * + * ReflectBlock -- + * + * This function is invoked to tell the channel which blocking behaviour + * is required of it. + * + * Results: + * A posix error number. + * + * Side effects: + * Allocates memory. Arbitrary, as it calls upon a script. + * + *---------------------------------------------------------------------- + */ + +static int +ReflectBlock( + ClientData clientData, + int nonblocking) +{ + ReflectedTransform *rtPtr = clientData; + + /* + * Transformations simply record the blocking mode in their C level + * structure for use by --> ReflectInput. The Tcl level doesn't see this + * information or change. As such thread forwarding is not required. + */ + + rtPtr->nonblocking = nonblocking; + return EOK; +} + +/* + *---------------------------------------------------------------------- + * + * ReflectSetOption -- + * + * This function is invoked to configure a channel option. + * + * Results: + * A standard Tcl result code. + * + * Side effects: + * Arbitrary, per the parent channel. + * + *---------------------------------------------------------------------- + */ + +static int +ReflectSetOption( + ClientData clientData, /* Channel to query */ + Tcl_Interp *interp, /* Interpreter to leave error messages in */ + const char *optionName, /* Name of requested option */ + const char *newValue) /* The new value */ +{ + ReflectedTransform *rtPtr = clientData; + + /* + * Transformations have no options. Thus the call is passed down unchanged + * to the parent channel for processing. Its results are passed back + * unchanged as well. This all happens in the thread we are in. As the Tcl + * level is not involved there is no need for thread forwarding. + */ + + Tcl_DriverSetOptionProc *setOptionProc = + Tcl_ChannelSetOptionProc(Tcl_GetChannelType(rtPtr->parent)); + + if (setOptionProc == NULL) { + return TCL_ERROR; + } + return setOptionProc(Tcl_GetChannelInstanceData(rtPtr->parent), interp, + optionName, newValue); +} + +/* + *---------------------------------------------------------------------- + * + * ReflectGetOption -- + * + * This function is invoked to retrieve all or a channel options. + * + * Results: + * A standard Tcl result code. + * + * Side effects: + * Arbitrary, per the parent channel. + * + *---------------------------------------------------------------------- + */ + +static int +ReflectGetOption( + ClientData clientData, /* Channel to query */ + Tcl_Interp *interp, /* Interpreter to leave error messages in */ + const char *optionName, /* Name of reuqested option */ + Tcl_DString *dsPtr) /* String to place the result into */ +{ + ReflectedTransform *rtPtr = clientData; + + /* + * Transformations have no options. Thus the call is passed down unchanged + * to the parent channel for processing. Its results are passed back + * unchanged as well. This all happens in the thread we are in. As the Tcl + * level is not involved there is no need for thread forwarding. + * + * Note that the parent not having a driver for option retrieval is not an + * immediate error. A query for all options is ok. Only a request for a + * specific option has to fail. + */ + + Tcl_DriverGetOptionProc *getOptionProc = + Tcl_ChannelGetOptionProc(Tcl_GetChannelType(rtPtr->parent)); + + if (getOptionProc != NULL) { + return getOptionProc(Tcl_GetChannelInstanceData(rtPtr->parent), + interp, optionName, dsPtr); + } else if (optionName == NULL) { + return TCL_OK; + } else { + return TCL_ERROR; + } +} + +/* + *---------------------------------------------------------------------- + * + * ReflectHandle -- + * + * This function is invoked to retrieve the associated file handle. + * + * Results: + * A standard Tcl result code. + * + * Side effects: + * Arbitrary, per the parent channel. + * + *---------------------------------------------------------------------- + */ + +static int +ReflectHandle( + ClientData clientData, + int direction, + ClientData *handlePtr) +{ + ReflectedTransform *rtPtr = clientData; + + /* + * Transformations have no handle of their own. As such we simply query + * the parent channel for it. This way the qery will ripple down through + * all transformations until reaches the base channel. Which then returns + * its handle, or fails. The former will then ripple up the stack. + * + * This all happens in the thread we are in. As the Tcl level is not + * involved no forwarding is required. + */ + + return Tcl_GetChannelHandle(rtPtr->parent, direction, handlePtr); +} +/* + *---------------------------------------------------------------------- + * + * ReflectNotify -- + * + * This function is invoked to reported incoming events. + * + * Results: + * A standard Tcl result code. + * + * Side effects: + * Arbitrary, per the parent channel. + * + *---------------------------------------------------------------------- + */ + +static int +ReflectNotify( + ClientData clientData, + int mask) +{ + ReflectedTransform *rtPtr = clientData; + + /* + * An event occured in the underlying channel. + * + * We delete our timer. It was not fired, yet we are here, so the channel + * below generated such an event and we don't have to. The renewal of the + * interest after the execution of channel handlers will eventually cause + * us to recreate the timer (in ReflectWatch). + */ + + TimerKill(rtPtr); + + /* + * Pass to higher layers. + */ + + return mask; +} + +/* + * Helpers. ========================================================= + */ + + +/* + *---------------------------------------------------------------------- + * + * DecodeEventMask -- + * + * This function takes an internal bitmask of events and constructs the + * equivalent list of event items. + * + * Results: + * A Tcl_Obj reference. The object will have a refCount of one. The user + * has to decrement it to release the object. + * + * Side effects: + * None. + * + *---------------------------------------------------------------------- + * DUPLICATE of 'DecodeEventMask' in tclIORChan.c + */ + +static Tcl_Obj * +DecodeEventMask( + int mask) +{ + register const char *eventStr; + Tcl_Obj *evObj; + + switch (mask & RANDW) { + case RANDW: + eventStr = "read write"; + break; + case TCL_READABLE: + eventStr = "read"; + break; + case TCL_WRITABLE: + eventStr = "write"; + break; + default: + eventStr = ""; + break; + } + + evObj = Tcl_NewStringObj(eventStr, -1); + Tcl_IncrRefCount(evObj); + return evObj; +} + +/* + *---------------------------------------------------------------------- + * + * NewReflectedTransform -- + * + * This function is invoked to allocate and initialize the instance data + * of a new reflected channel. + * + * Results: + * A heap-allocated channel instance. + * + * Side effects: + * Allocates memory. + * + *---------------------------------------------------------------------- + */ + +static ReflectedTransform * +NewReflectedTransform( + Tcl_Interp *interp, + Tcl_Obj *cmdpfxObj, + int mode, + Tcl_Obj *handleObj, + Tcl_Channel parentChan) +{ + ReflectedTransform *rtPtr; + int listc; + Tcl_Obj **listv; + int i; + + rtPtr = (ReflectedTransform *) ckalloc(sizeof(ReflectedTransform)); + + /* rtPtr->chan: Assigned by caller. Dummy data here. */ + /* rtPtr->methods: Assigned by caller. Dummy data here. */ + + rtPtr->chan = NULL; + rtPtr->methods = 0; +#ifdef TCL_THREADS + rtPtr->thread = Tcl_GetCurrentThread(); +#endif + rtPtr->parent = parentChan; + rtPtr->interp = interp; + rtPtr->handle = handleObj; + Tcl_IncrRefCount(handleObj); + rtPtr->timer = NULL; + rtPtr->mode = 0; + rtPtr->readIsDrained = 0; + rtPtr->nonblocking = + (((Channel *) parentChan)->state->flags & CHANNEL_NONBLOCKING); + + /* + * Query parent for current blocking mode. + */ + + ResultInit(&rtPtr->result); + + /* + * Method placeholder. + */ + + /* ASSERT: cmdpfxObj is a Tcl List */ + + Tcl_ListObjGetElements(interp, cmdpfxObj, &listc, &listv); + + /* + * See [==] as well. + * Storage for the command prefix and the additional words required for + * the invocation of methods in the command handler. + * + * listv [0] [listc-1] | [listc] [listc+1] | + * argv [0] ... [.] | [argc-2] [argc-1] | [argc] [argc+2] + * cmd ... pfx | method chan | detail1 detail2 + */ + + rtPtr->argc = listc + 2; + rtPtr->argv = (Tcl_Obj **) ckalloc(sizeof(Tcl_Obj *) * (listc+4)); + + /* + * Duplicate object references. + */ + + for (i=0; i<listc ; i++) { + Tcl_Obj *word = rtPtr->argv[i] = listv[i]; + + Tcl_IncrRefCount(word); + } + + i++; /* Skip placeholder for method */ + + /* + * See [x] in FreeReflectedTransform for release + */ + rtPtr->argv[i] = handleObj; + Tcl_IncrRefCount(handleObj); + + /* + * The next two objects are kept empty, varying arguments. + */ + + /* + * Initialization complete. + */ + + return rtPtr; +} + +/* + *---------------------------------------------------------------------- + * + * NextHandle -- + * + * This function is invoked to generate a channel handle for a new + * reflected channel. + * + * Results: + * A Tcl_Obj containing the string of the new channel handle. The + * refcount of the returned object is -- zero --. + * + * Side effects: + * May allocate memory. Mutex protected critical section locks out other + * threads for a short time. + * + *---------------------------------------------------------------------- + */ + +static Tcl_Obj * +NextHandle(void) +{ + /* + * Count number of generated reflected channels. Used for id generation. + * Ids are never reclaimed and there is no dealing with wrap around. On + * the other hand, "unsigned long" should be big enough except for + * absolute longrunners (generate a 100 ids per second => overflow will + * occur in 1 1/3 years). + */ + + TCL_DECLARE_MUTEX(rtCounterMutex) + static unsigned long rtCounter = 0; + Tcl_Obj *resObj; + + Tcl_MutexLock(&rtCounterMutex); + resObj = Tcl_ObjPrintf("rt%lu", rtCounter); + rtCounter++; + Tcl_MutexUnlock(&rtCounterMutex); + + return resObj; +} + +static void +FreeReflectedTransform( + ReflectedTransform *rtPtr) +{ + int i, n; + + TimerKill(rtPtr); + ResultClear(&rtPtr->result); + + Tcl_DecrRefCount(rtPtr->handle); + rtPtr->handle = NULL; + + n = rtPtr->argc - 2; + for (i=0; i<n; i++) { + Tcl_DecrRefCount(rtPtr->argv[i]); + } + + /* + * See [x] in NewReflectedTransform for lock + * n+1 = argc-1. + */ + Tcl_DecrRefCount(rtPtr->argv[n+1]); + + ckfree((char*) rtPtr->argv); + ckfree((char*) rtPtr); +} + +/* + *---------------------------------------------------------------------- + * + * InvokeTclMethod -- + * + * This function is used to invoke the Tcl level of a reflected channel. + * It handles all the command assembly, invokation, and generic state and + * result mgmt. It does *not* handle thread redirection; that is the + * responsibility of clients of this function. + * + * Results: + * Result code and data as returned by the method. + * + * Side effects: + * Arbitrary, as it calls upon a Tcl script. + * + * Contract: + * argOneObj.refCount >= 1 on entry and exit, if argOneObj != NULL + * argTwoObj.refCount >= 1 on entry and exit, if argTwoObj != NULL + * resObj.refCount in {0, 1, ...} + * + *---------------------------------------------------------------------- + * Semi-DUPLICATE of 'InvokeTclMethod' in tclIORChan.c + * - Semi because different structures are used. + * - Still possible to factor out the commonalities into a separate structure. + */ + +static int +InvokeTclMethod( + ReflectedTransform *rtPtr, + const char *method, + Tcl_Obj *argOneObj, /* NULL'able */ + Tcl_Obj *argTwoObj, /* NULL'able */ + Tcl_Obj **resultObjPtr) /* NULL'able */ +{ + int cmdc; /* #words in constructed command */ + Tcl_Obj *methObj = NULL; /* Method name in object form */ + Tcl_InterpState sr; /* State of handler interp */ + int result; /* Result code of method invokation */ + Tcl_Obj *resObj = NULL; /* Result of method invokation. */ + + if (!rtPtr->interp) { + /* + * The transform is marked as dead. Bail out immediately, with an + * appropriate error. + */ + + if (resultObjPtr != NULL) { + resObj = Tcl_NewStringObj(msg_dstlost,-1); + *resultObjPtr = resObj; + Tcl_IncrRefCount(resObj); + } + return TCL_ERROR; + } + + /* + * NOTE (5): Decide impl. issue: Cache objects with method names? + * Requires TSD data as reflections can be created in many different + * threads. + * NO: Caching of command resolutions means storage per channel. + */ + + /* + * Insert method into the pre-allocated area, after the command prefix, + * before the channel id. + */ + + methObj = Tcl_NewStringObj(method, -1); + Tcl_IncrRefCount(methObj); + rtPtr->argv[rtPtr->argc - 2] = methObj; + + /* + * Append the additional argument containing method specific details + * behind the channel id. If specified. + * + * Because of the contract there is no need to increment the refcounts. + * The objects will survive the Tcl_EvalObjv without change. + */ + + cmdc = rtPtr->argc; + if (argOneObj) { + rtPtr->argv[cmdc] = argOneObj; + cmdc++; + if (argTwoObj) { + rtPtr->argv[cmdc] = argTwoObj; + cmdc++; + } + } + + /* + * And run the handler... This is done in auch a manner which leaves any + * existing state intact. + */ + + sr = Tcl_SaveInterpState(rtPtr->interp, 0 /* Dummy */); + Tcl_Preserve(rtPtr); + result = Tcl_EvalObjv(rtPtr->interp, cmdc, rtPtr->argv, TCL_EVAL_GLOBAL); + + /* + * We do not try to extract the result information if the caller has no + * interest in it. I.e. there is no need to put effort into creating + * something which is discarded immediately after. + */ + + if (resultObjPtr) { + if (result == TCL_OK) { + /* + * Ok result taken as is, also if the caller requests that there + * is no capture. + */ + + resObj = Tcl_GetObjResult(rtPtr->interp); + } else { + /* + * Non-ok result is always treated as an error. We have to capture + * the full state of the result, including additional options. + * + * This is complex and ugly, and would be completely unnecessary + * if we only added support for a TCL_FORBID_EXCEPTIONS flag. + */ + if (result != TCL_ERROR) { + Tcl_Obj *cmd = Tcl_NewListObj(cmdc, rtPtr->argv); + int cmdLen; + const char *cmdString = Tcl_GetStringFromObj(cmd, &cmdLen); + + Tcl_IncrRefCount(cmd); + Tcl_ResetResult(rtPtr->interp); + Tcl_SetObjResult(rtPtr->interp, Tcl_ObjPrintf( + "chan handler returned bad code: %d", result)); + Tcl_LogCommandInfo(rtPtr->interp, cmdString, cmdString, cmdLen); + Tcl_DecrRefCount(cmd); + result = TCL_ERROR; + } + Tcl_AppendObjToErrorInfo(rtPtr->interp, Tcl_ObjPrintf( + "\n (chan handler subcommand \"%s\")", method)); + resObj = MarshallError(rtPtr->interp); + } + Tcl_IncrRefCount(resObj); + } + Tcl_RestoreInterpState(rtPtr->interp, sr); + Tcl_Release(rtPtr); + + /* + * Cleanup of the dynamic parts of the command. + * + * The detail objects survived the Tcl_EvalObjv without change because of + * the contract. Therefore there is no need to decrement the refcounts. Only + * the internal method object has to be disposed of. + */ + + Tcl_DecrRefCount(methObj); + + /* + * The resObj has a ref count of 1 at this location. This means that the + * caller of InvokeTclMethod has to dispose of it (but only if it was + * returned to it). + */ + + if (resultObjPtr != NULL) { + *resultObjPtr = resObj; + } + + /* + * There no need to handle the case where nothing is returned, because for + * that case resObj was not set anyway. + */ + + return result; +} + +/* + *---------------------------------------------------------------------- + * + * GetReflectedTransformMap -- + * + * Gets and potentially initializes the reflected channel map for an + * interpreter. + * + * Results: + * A pointer to the map created, for use by the caller. + * + * Side effects: + * Initializes the reflected channel map for an interpreter. + * + *---------------------------------------------------------------------- + */ + +static ReflectedTransformMap * +GetReflectedTransformMap( + Tcl_Interp *interp) +{ + ReflectedTransformMap *rtmPtr = Tcl_GetAssocData(interp, RTMKEY, NULL); + + if (rtmPtr == NULL) { + rtmPtr = (ReflectedTransformMap *) + ckalloc(sizeof(ReflectedTransformMap)); + Tcl_InitHashTable(&rtmPtr->map, TCL_STRING_KEYS); + Tcl_SetAssocData(interp, RTMKEY, + (Tcl_InterpDeleteProc *) DeleteReflectedTransformMap, rtmPtr); + } + return rtmPtr; +} + +/* + *---------------------------------------------------------------------- + * + * DeleteReflectedTransformMap -- + * + * Deletes the channel table for an interpreter, closing any open + * channels whose refcount reaches zero. This procedure is invoked when + * an interpreter is deleted, via the AssocData cleanup mechanism. + * + * Results: + * None. + * + * Side effects: + * Deletes the hash table of channels. May close channels. May flush + * output on closed channels. Removes any channeEvent handlers that were + * registered in this interpreter. + * + *---------------------------------------------------------------------- + */ + +static void +DeleteReflectedTransformMap( + ClientData clientData, /* The per-interpreter data structure. */ + Tcl_Interp *interp) /* The interpreter being deleted. */ +{ + ReflectedTransformMap *rtmPtr; /* The map */ + Tcl_HashSearch hSearch; /* Search variable. */ + Tcl_HashEntry *hPtr; /* Search variable. */ + ReflectedTransform *rtPtr; +#ifdef TCL_THREADS + ForwardingResult *resultPtr; + ForwardingEvent *evPtr; + ForwardParam *paramPtr; +#endif + + /* + * Delete all entries. The channels may have been closed already, or will + * be closed later, by the standard IO finalization of an interpreter + * under destruction. Except for the channels which were moved to a + * different interpreter and/or thread. They do not exist from the IO + * systems point of view and will not get closed. Therefore mark all as + * dead so that any future access will cause a proper error. For channels + * in a different thread we actually do the same as + * DeleteThreadReflectedTransformMap(), just restricted to the channels of + * this interp. + */ + + rtmPtr = clientData; + for (hPtr = Tcl_FirstHashEntry(&rtmPtr->map, &hSearch); + hPtr != NULL; + hPtr = Tcl_FirstHashEntry(&rtmPtr->map, &hSearch)) { + rtPtr = Tcl_GetHashValue(hPtr); + rtPtr->interp = NULL; + Tcl_DeleteHashEntry(hPtr); + } + Tcl_DeleteHashTable(&rtmPtr->map); + ckfree((char *) &rtmPtr->map); + +#ifdef TCL_THREADS + /* + * The origin interpreter for one or more reflected channels is gone. + */ + + /* + * Go through the list of pending results and cancel all whose events were + * destined for this interpreter. While this is in progress we block any + * other access to the list of pending results. + */ + + Tcl_MutexLock(&rtForwardMutex); + + for (resultPtr = forwardList; resultPtr != NULL; + resultPtr = resultPtr->nextPtr) { + if (resultPtr->dsti != interp) { + /* + * Ignore results/events for other interpreters. + */ + + continue; + } + + /* + * The receiver for the event exited, before processing the event. We + * detach the result now, wake the originator up and signal failure. + */ + + evPtr = resultPtr->evPtr; + paramPtr = evPtr->param; + + evPtr->resultPtr = NULL; + resultPtr->evPtr = NULL; + resultPtr->result = TCL_ERROR; + + ForwardSetStaticError(paramPtr, msg_send_dstlost); + + Tcl_ConditionNotify(&resultPtr->done); + } + + /* + * Get the map of all channels handled by the current thread. This is a + * ReflectedTransformMap, but on a per-thread basis, not per-interp. Go + * through the channels and remove all which were handled by this + * interpreter. They have already been marked as dead. + */ + + rtmPtr = GetThreadReflectedTransformMap(); + for (hPtr = Tcl_FirstHashEntry(&rtmPtr->map, &hSearch); + hPtr != NULL; + hPtr = Tcl_NextHashEntry(&hSearch)) { + rtPtr = Tcl_GetHashValue(hPtr); + + if (rtPtr->interp != interp) { + /* + * Ignore entries for other interpreters. + */ + + continue; + } + + Tcl_DeleteHashEntry(hPtr); + } + + Tcl_MutexUnlock(&rtForwardMutex); +#endif +} + +#ifdef TCL_THREADS +/* + *---------------------------------------------------------------------- + * + * GetThreadReflectedTransformMap -- + * + * Gets and potentially initializes the reflected channel map for a + * thread. + * + * Results: + * A pointer to the map created, for use by the caller. + * + * Side effects: + * Initializes the reflected channel map for a thread. + * + *---------------------------------------------------------------------- + */ + +static ReflectedTransformMap * +GetThreadReflectedTransformMap(void) +{ + ThreadSpecificData *tsdPtr = TCL_TSD_INIT(&dataKey); + + if (!tsdPtr->rtmPtr) { + tsdPtr->rtmPtr = (ReflectedTransformMap *) + ckalloc(sizeof(ReflectedTransformMap)); + Tcl_InitHashTable(&tsdPtr->rtmPtr->map, TCL_STRING_KEYS); + Tcl_CreateThreadExitHandler(DeleteThreadReflectedTransformMap, NULL); + } + + return tsdPtr->rtmPtr; +} + +/* + *---------------------------------------------------------------------- + * + * DeleteThreadReflectedTransformMap -- + * + * Deletes the channel table for a thread. This procedure is invoked when + * a thread is deleted. The channels have already been marked as dead, in + * DeleteReflectedTransformMap(). + * + * Results: + * None. + * + * Side effects: + * Deletes the hash table of channels. + * + *---------------------------------------------------------------------- + */ + +static void +DeleteThreadReflectedTransformMap( + ClientData clientData) /* The per-thread data structure. */ +{ + Tcl_HashSearch hSearch; /* Search variable. */ + Tcl_HashEntry *hPtr; /* Search variable. */ + Tcl_ThreadId self = Tcl_GetCurrentThread(); + ReflectedTransformMap *rtmPtr; /* The map */ + ForwardingResult *resultPtr; + + /* + * The origin thread for one or more reflected channels is gone. + * NOTE: If this function is called due to a thread getting killed the + * per-interp DeleteReflectedTransformMap is apparently not called. + */ + + /* + * Go through the list of pending results and cancel all whose events were + * destined for this thread. While this is in progress we block any + * other access to the list of pending results. + */ + + Tcl_MutexLock(&rtForwardMutex); + + for (resultPtr = forwardList; resultPtr != NULL; + resultPtr = resultPtr->nextPtr) { + ForwardingEvent *evPtr; + ForwardParam *paramPtr; + + if (resultPtr->dst != self) { + /* + * Ignore results/events for other threads. + */ + + continue; + } + + /* + * The receiver for the event exited, before processing the event. We + * detach the result now, wake the originator up and signal failure. + */ + + evPtr = resultPtr->evPtr; + paramPtr = evPtr->param; + + evPtr->resultPtr = NULL; + resultPtr->evPtr = NULL; + resultPtr->result = TCL_ERROR; + + ForwardSetStaticError(paramPtr, msg_send_dstlost); + + Tcl_ConditionNotify(&resultPtr->done); + } + + /* + * Get the map of all channels handled by the current thread. This is a + * ReflectedTransformMap, but on a per-thread basis, not per-interp. Go + * through the channels, remove all, mark them as dead. + */ + + rtmPtr = GetThreadReflectedTransformMap(); + for (hPtr = Tcl_FirstHashEntry(&rtmPtr->map, &hSearch); + hPtr != NULL; + hPtr = Tcl_FirstHashEntry(&rtmPtr->map, &hSearch)) { + ReflectedTransform *rtPtr = Tcl_GetHashValue(hPtr); + + rtPtr->interp = NULL; + Tcl_DeleteHashEntry(hPtr); + } + + Tcl_MutexUnlock(&rtForwardMutex); +} + +static void +ForwardOpToOwnerThread( + ReflectedTransform *rtPtr, /* Channel instance */ + ForwardedOperation op, /* Forwarded driver operation */ + const void *param) /* Arguments */ +{ + Tcl_ThreadId dst = rtPtr->thread; + ForwardingEvent *evPtr; + ForwardingResult *resultPtr; + int result; + + /* + * We gather the lock early. This allows us to check the liveness of the + * channel without interference from DeleteThreadReflectedTransformMap(). + */ + + Tcl_MutexLock(&rtForwardMutex); + + if (rtPtr->interp == NULL) { + /* + * The channel is marked as dead. Bail out immediately, with an + * appropriate error. Do not forget to unlock the mutex on this path. + */ + + ForwardSetStaticError((ForwardParam *) param, msg_send_dstlost); + Tcl_MutexUnlock(&rtForwardMutex); + return; + } + + /* + * Create and initialize the event and data structures. + */ + + evPtr = (ForwardingEvent *) ckalloc(sizeof(ForwardingEvent)); + resultPtr = (ForwardingResult *) ckalloc(sizeof(ForwardingResult)); + + evPtr->event.proc = ForwardProc; + evPtr->resultPtr = resultPtr; + evPtr->op = op; + evPtr->rtPtr = rtPtr; + evPtr->param = (ForwardParam *) param; + + resultPtr->src = Tcl_GetCurrentThread(); + resultPtr->dst = dst; + resultPtr->done = NULL; + resultPtr->result = -1; + resultPtr->evPtr = evPtr; + + /* + * Now execute the forward. + */ + + TclSpliceIn(resultPtr, forwardList); + /* Do not unlock here. That is done by the ConditionWait */ + + /* + * Ensure cleanup of the event if the origin thread exits while this event + * is pending or in progress. Exit of the destination thread is handled by + * DeleteThreadReflectionChannelMap(), this is set up by + * GetThreadReflectedTransformMap(). This is what we use the 'forwardList' + * (see above) for. + */ + + Tcl_CreateThreadExitHandler(SrcExitProc, evPtr); + + /* + * Queue the event and poke the other thread's notifier. + */ + + Tcl_ThreadQueueEvent(dst, (Tcl_Event *) evPtr, TCL_QUEUE_TAIL); + Tcl_ThreadAlert(dst); + + /* + * (*) Block until the other thread has either processed the transfer or + * rejected it. + */ + + while (resultPtr->result < 0) { + /* + * NOTE (1): Is it possible that the current thread goes away while + * waiting here? IOW Is it possible that "SrcExitProc" is called + * while we are here? See complementary note (2) in "SrcExitProc" + * + * The ConditionWait unlocks the mutex during the wait and relocks it + * immediately after. + */ + + Tcl_ConditionWait(&resultPtr->done, &rtForwardMutex, NULL); + } + + /* + * Unlink result from the forwarder list. No need to lock. Either still + * locked, or locked by the ConditionWait + */ + + TclSpliceOut(resultPtr, forwardList); + + resultPtr->nextPtr = NULL; + resultPtr->prevPtr = NULL; + + Tcl_MutexUnlock(&rtForwardMutex); + Tcl_ConditionFinalize(&resultPtr->done); + + /* + * Kill the cleanup handler now, and the result structure as well, before + * returning the success code. + * + * Note: The event structure has already been deleted by the destination + * notifier, after it serviced the event. + */ + + Tcl_DeleteThreadExitHandler(SrcExitProc, evPtr); + + result = resultPtr->result; + ckfree((char*) resultPtr); +} + +static int +ForwardProc( + Tcl_Event *evGPtr, + int mask) +{ + /* + * Notes regarding access to the referenced data. + * + * In principle the data belongs to the originating thread (see + * evPtr->src), however this thread is currently blocked at (*), i.e. + * quiescent. Because of this we can treat the data as belonging to us, + * without fear of race conditions. I.e. we can read and write as we like. + * + * The only thing we cannot be sure of is the resultPtr. This can be be + * NULLed if the originating thread went away while the event is handled + * here now. + */ + + ForwardingEvent *evPtr = (ForwardingEvent *) evGPtr; + ForwardingResult *resultPtr = evPtr->resultPtr; + ReflectedTransform *rtPtr = evPtr->rtPtr; + Tcl_Interp *interp = rtPtr->interp; + ForwardParam *paramPtr = evPtr->param; + Tcl_Obj *resObj = NULL; /* Interp result of InvokeTclMethod */ + ReflectedTransformMap *rtmPtr; + /* Map of reflected channels with handlers in + * this interp. */ + Tcl_HashEntry *hPtr; /* Entry in the above map */ + + /* + * Ignore the event if no one is waiting for its result anymore. + */ + + if (!resultPtr) { + return 1; + } + + paramPtr->base.code = TCL_OK; + paramPtr->base.msgStr = NULL; + paramPtr->base.mustFree = 0; + + switch (evPtr->op) { + /* + * The destination thread for the following operations is + * rtPtr->thread, which contains rtPtr->interp, the interp we have to + * call upon for the driver. + */ + + case ForwardedClose: + /* + * No parameters/results. + */ + + if (InvokeTclMethod(rtPtr, "finalize", NULL, NULL, + &resObj) != TCL_OK) { + ForwardSetObjError(paramPtr, resObj); + } + + /* + * Freeing is done here, in the origin thread, because the argv[] + * objects belong to this thread. Deallocating them in a different + * thread is not allowed + */ + + /* + * Remove the channel from the map before releasing the memory, to + * prevent future accesses (like by 'postevent') from finding and + * dereferencing a dangling pointer. + */ + + rtmPtr = GetReflectedTransformMap(interp); + hPtr = Tcl_FindHashEntry(&rtmPtr->map, Tcl_GetString(rtPtr->handle)); + Tcl_DeleteHashEntry(hPtr); + + /* + * In a threaded interpreter we manage a per-thread map as well, to + * allow us to survive if the script level pulls the rug out under a + * channel by deleting the owning thread. + */ + + rtmPtr = GetThreadReflectedTransformMap(); + hPtr = Tcl_FindHashEntry(&rtmPtr->map, Tcl_GetString(rtPtr->handle)); + Tcl_DeleteHashEntry(hPtr); + + Tcl_EventuallyFree (rtPtr, (Tcl_FreeProc *) FreeReflectedTransform); + break; + + case ForwardedInput: { + Tcl_Obj *bufObj = Tcl_NewByteArrayObj((unsigned char *) + paramPtr->transform.buf, paramPtr->transform.size); + Tcl_IncrRefCount(bufObj); + + if (InvokeTclMethod(rtPtr, "read", bufObj, NULL, &resObj) != TCL_OK) { + ForwardSetObjError(paramPtr, resObj); + paramPtr->transform.size = -1; + } else { + /* + * Process a regular return. Contains the transformation result. + * Sent it back to the request originator. + */ + + int bytec; /* Number of returned bytes */ + unsigned char *bytev; + /* Array of returned bytes */ + + bytev = Tcl_GetByteArrayFromObj(resObj, &bytec); + + paramPtr->transform.size = bytec; + + if (bytec > 0) { + paramPtr->transform.buf = ckalloc(bytec); + memcpy(paramPtr->transform.buf, bytev, (size_t)bytec); + } else { + paramPtr->transform.buf = NULL; + } + } + + Tcl_DecrRefCount(bufObj); + break; + } + + case ForwardedOutput: { + Tcl_Obj *bufObj = Tcl_NewByteArrayObj((unsigned char *) + paramPtr->transform.buf, paramPtr->transform.size); + Tcl_IncrRefCount(bufObj); + + if (InvokeTclMethod(rtPtr, "write", bufObj, NULL, &resObj) != TCL_OK) { + ForwardSetObjError(paramPtr, resObj); + paramPtr->transform.size = -1; + } else { + /* + * Process a regular return. Contains the transformation result. + * Sent it back to the request originator. + */ + + int bytec; /* Number of returned bytes */ + unsigned char *bytev; + /* Array of returned bytes */ + + bytev = Tcl_GetByteArrayFromObj(resObj, &bytec); + + paramPtr->transform.size = bytec; + + if (bytec > 0) { + paramPtr->transform.buf = ckalloc(bytec); + memcpy(paramPtr->transform.buf, bytev, (size_t)bytec); + } else { + paramPtr->transform.buf = NULL; + } + } + + Tcl_DecrRefCount(bufObj); + break; + } + + case ForwardedDrain: { + if (InvokeTclMethod(rtPtr, "drain", NULL, NULL, &resObj) != TCL_OK) { + ForwardSetObjError(paramPtr, resObj); + paramPtr->transform.size = -1; + } else { + /* + * Process a regular return. Contains the transformation result. + * Sent it back to the request originator. + */ + + int bytec; /* Number of returned bytes */ + unsigned char *bytev; /* Array of returned bytes */ + + bytev = Tcl_GetByteArrayFromObj(resObj, &bytec); + + paramPtr->transform.size = bytec; + + if (bytec > 0) { + paramPtr->transform.buf = ckalloc(bytec); + memcpy(paramPtr->transform.buf, bytev, (size_t)bytec); + } else { + paramPtr->transform.buf = NULL; + } + } + break; + } + + case ForwardedFlush: { + if (InvokeTclMethod(rtPtr, "flush", NULL, NULL, &resObj) != TCL_OK) { + ForwardSetObjError(paramPtr, resObj); + paramPtr->transform.size = -1; + } else { + /* + * Process a regular return. Contains the transformation result. + * Sent it back to the request originator. + */ + + int bytec; /* Number of returned bytes */ + unsigned char *bytev; + /* Array of returned bytes */ + + bytev = Tcl_GetByteArrayFromObj(resObj, &bytec); + + paramPtr->transform.size = bytec; + + if (bytec > 0) { + paramPtr->transform.buf = ckalloc(bytec); + memcpy(paramPtr->transform.buf, bytev, (size_t)bytec); + } else { + paramPtr->transform.buf = NULL; + } + } + break; + } + + case ForwardedClear: { + (void) InvokeTclMethod(rtPtr, "clear", NULL, NULL, NULL); + break; + } + + case ForwardedLimit: + if (InvokeTclMethod(rtPtr, "limit?", NULL, NULL, &resObj) != TCL_OK) { + ForwardSetObjError(paramPtr, resObj); + paramPtr->limit.max = -1; + } else if (Tcl_GetIntFromObj(interp, resObj, + ¶mPtr->limit.max) != TCL_OK) { + ForwardSetObjError(paramPtr, MarshallError(interp)); + paramPtr->limit.max = -1; + } + break; + + default: + /* + * Bad operation code. + */ + Tcl_Panic("Bad operation code in ForwardProc"); + break; + } + + /* + * Remove the reference we held on the result of the invoke, if we had + * such. + */ + + if (resObj != NULL) { + Tcl_DecrRefCount(resObj); + } + + if (resultPtr) { + /* + * Report the forwarding result synchronously to the waiting caller. + * This unblocks (*) as well. This is wrapped into a conditional + * because the caller may have exited in the mean time. + */ + + Tcl_MutexLock(&rtForwardMutex); + resultPtr->result = TCL_OK; + Tcl_ConditionNotify(&resultPtr->done); + Tcl_MutexUnlock(&rtForwardMutex); + } + + return 1; +} + +static void +SrcExitProc( + ClientData clientData) +{ + ForwardingEvent *evPtr = clientData; + ForwardingResult *resultPtr; + ForwardParam *paramPtr; + + /* + * NOTE (2): Can this handler be called with the originator blocked? + */ + + /* + * The originator for the event exited. It is not sure if this can happen, + * as the originator should be blocked at (*) while the event is in + * transit/pending. + * + * We make sure that the event cannot refer to the result anymore, remove + * it from the list of pending results and free the structure. Locking the + * access ensures that we cannot get in conflict with "ForwardProc", + * should it already execute the event. + */ + + Tcl_MutexLock(&rtForwardMutex); + + resultPtr = evPtr->resultPtr; + paramPtr = evPtr->param; + + evPtr->resultPtr = NULL; + resultPtr->evPtr = NULL; + resultPtr->result = TCL_ERROR; + + ForwardSetStaticError(paramPtr, msg_send_originlost); + + /* + * See below: TclSpliceOut(resultPtr, forwardList); + */ + + Tcl_MutexUnlock(&rtForwardMutex); + + /* + * This unlocks (*). The structure will be spliced out and freed by + * "ForwardProc". Maybe. + */ + + Tcl_ConditionNotify(&resultPtr->done); +} + +static void +ForwardSetObjError( + ForwardParam *paramPtr, + Tcl_Obj *obj) +{ + int len; + const char *msgStr = Tcl_GetStringFromObj(obj, &len); + + len++; + ForwardSetDynamicError(paramPtr, ckalloc((unsigned) len)); + memcpy(paramPtr->base.msgStr, msgStr, (unsigned) len); +} +#endif + +/* + *---------------------------------------------------------------------- + * + * TimerKill -- + * + * Timer management. Removes the internal timer if it exists. + * + * Side effects: + * See above. + * + * Result: + * None. + * + *---------------------------------------------------------------------- + */ + +static void +TimerKill( + ReflectedTransform *rtPtr) +{ + if (rtPtr->timer == NULL) { + return; + } + + /* + * Delete an existing flush-out timer, prevent it from firing on a + * removed/dead channel. + */ + + Tcl_DeleteTimerHandler(rtPtr->timer); + rtPtr->timer = NULL; +} + +/* + *---------------------------------------------------------------------- + * + * TimerSetup -- + * + * Timer management. Creates the internal timer if it does not exist. + * + * Side effects: + * See above. + * + * Result: + * None. + * + *---------------------------------------------------------------------- + */ + +static void +TimerSetup( + ReflectedTransform *rtPtr) +{ + if (rtPtr->timer != NULL) { + return; + } + + rtPtr->timer = Tcl_CreateTimerHandler(FLUSH_DELAY, TimerRun, rtPtr); +} + +/* + *---------------------------------------------------------------------- + * + * TimerRun -- + * + * Called by the notifier (-> timer) to flush out information waiting in + * channel buffers. + * + * Side effects: + * As of 'Tcl_NotifyChannel'. + * + * Result: + * None. + * + *---------------------------------------------------------------------- + */ + +static void +TimerRun( + ClientData clientData) +{ + ReflectedTransform *rtPtr = clientData; + + rtPtr->timer = NULL; + Tcl_NotifyChannel(rtPtr->chan, TCL_READABLE); +} + +/* + *---------------------------------------------------------------------- + * + * ResultInit -- + * + * Initializes the specified buffer structure. The structure will contain + * valid information for an emtpy buffer. + * + * Side effects: + * See above. + * + * Result: + * None. + * + *---------------------------------------------------------------------- + */ + +static void +ResultInit( + ResultBuffer *rPtr) /* Reference to the structure to + * initialize. */ +{ + rPtr->used = 0; + rPtr->allocated = 0; + rPtr->buf = NULL; +} +/* + *---------------------------------------------------------------------- + * + * ResultClear -- + * + * Deallocates any memory allocated by 'ResultAdd'. + * + * Side effects: + * See above. + * + * Result: + * None. + * + *---------------------------------------------------------------------- + */ + +static void +ResultClear( + ResultBuffer *rPtr) /* Reference to the buffer to clear out */ +{ + rPtr->used = 0; + + if (!rPtr->allocated) { + return; + } + + Tcl_Free((char *) rPtr->buf); + rPtr->buf = NULL; + rPtr->allocated = 0; +} + +/* + *---------------------------------------------------------------------- + * + * ResultAdd -- + * + * Adds the bytes in the specified array to the buffer, by appending it. + * + * Side effects: + * See above. + * + * Result: + * None. + * + *---------------------------------------------------------------------- + */ + +static void +ResultAdd( + ResultBuffer *rPtr, /* The buffer to extend */ + unsigned char *buf, /* The buffer to read from */ + int toWrite) /* The number of bytes in 'buf' */ +{ + if ((rPtr->used + toWrite + 1) > rPtr->allocated) { + /* + * Extension of the internal buffer is required. + * NOTE: Currently linear. Should be doubling to amortize. + */ + + if (rPtr->allocated == 0) { + rPtr->allocated = toWrite + RB_INCREMENT; + rPtr->buf = UCHARP(Tcl_Alloc(rPtr->allocated)); + } else { + rPtr->allocated += toWrite + RB_INCREMENT; + rPtr->buf = UCHARP(Tcl_Realloc((char *) rPtr->buf, + rPtr->allocated)); + } + } + + /* + * Now copy data. + */ + + memcpy(rPtr->buf + rPtr->used, buf, toWrite); + rPtr->used += toWrite; +} + +/* + *---------------------------------------------------------------------- + * + * ResultCopy -- + * + * Copies the requested number of bytes from the buffer into the + * specified array and removes them from the buffer afterward. Copies + * less if there is not enough data in the buffer. + * + * Side effects: + * See above. + * + * Result: + * The number of actually copied bytes, possibly less than 'toRead'. + * + *---------------------------------------------------------------------- + */ + +static int +ResultCopy( + ResultBuffer *rPtr, /* The buffer to read from */ + unsigned char *buf, /* The buffer to copy into */ + int toRead) /* Number of requested bytes */ +{ + int copied; + + if (rPtr->used == 0) { + /* + * Nothing to copy in the case of an empty buffer. + */ + + copied = 0; + } else if (rPtr->used == toRead) { + /* + * We have just enough. Copy everything to the caller. + */ + + memcpy(buf, rPtr->buf, toRead); + rPtr->used = 0; + copied = toRead; + } else if (rPtr->used > toRead) { + /* + * The internal buffer contains more than requested. Copy the + * requested subset to the caller, and shift the remaining bytes down. + */ + + memcpy(buf, rPtr->buf, toRead); + memmove(rPtr->buf, rPtr->buf + toRead, rPtr->used - toRead); + + rPtr->used -= toRead; + copied = toRead; + } else { + /* + * There is not enough in the buffer to satisfy the caller, so take + * everything. + */ + + memcpy(buf, rPtr->buf, rPtr->used); + toRead = rPtr->used; + rPtr->used = 0; + copied = toRead; + } + + /* -- common postwork code ------- */ + + return copied; +} + +static int +TransformRead( + ReflectedTransform *rtPtr, + int *errorCodePtr, + unsigned char *buf, + int toRead) +{ + Tcl_Obj *bufObj; + Tcl_Obj *resObj; + int bytec; /* Number of returned bytes */ + unsigned char *bytev; /* Array of returned bytes */ + + /* + * Are we in the correct thread? + */ + +#ifdef TCL_THREADS + if (rtPtr->thread != Tcl_GetCurrentThread()) { + ForwardParam p; + + p.transform.buf = (char *) buf; + p.transform.size = toRead; + + ForwardOpToOwnerThread(rtPtr, ForwardedInput, &p); + + if (p.base.code != TCL_OK) { + PassReceivedError(rtPtr->chan, &p); + *errorCodePtr = EINVAL; + return 0; + } + + *errorCodePtr = EOK; + ResultAdd(&rtPtr->result, UCHARP(p.transform.buf), p.transform.size); + ckfree(p.transform.buf); + return 1; + } +#endif + + /* ASSERT: rtPtr->method & FLAG(METH_READ) */ + /* ASSERT: rtPtr->mode & TCL_READABLE */ + + bufObj = Tcl_NewByteArrayObj((unsigned char *) buf, toRead); + Tcl_IncrRefCount(bufObj); + + if (InvokeTclMethod(rtPtr, "read", bufObj, NULL, &resObj) != TCL_OK) { + Tcl_SetChannelError(rtPtr->chan, resObj); + Tcl_DecrRefCount(bufObj); + Tcl_DecrRefCount(resObj); /* Remove reference held from invoke */ + *errorCodePtr = EINVAL; + return 0; + } + + bytev = Tcl_GetByteArrayFromObj(resObj, &bytec); + ResultAdd(&rtPtr->result, bytev, bytec); + + Tcl_DecrRefCount(bufObj); + Tcl_DecrRefCount(resObj); /* Remove reference held from invoke */ + return 1; +} + +static int +TransformWrite( + ReflectedTransform *rtPtr, + int *errorCodePtr, + unsigned char *buf, + int toWrite) +{ + Tcl_Obj *bufObj; + Tcl_Obj *resObj; + int bytec; /* Number of returned bytes */ + unsigned char *bytev; /* Array of returned bytes */ + int res; + + /* + * Are we in the correct thread? + */ + +#ifdef TCL_THREADS + if (rtPtr->thread != Tcl_GetCurrentThread()) { + ForwardParam p; + + p.transform.buf = (char *) buf; + p.transform.size = toWrite; + + ForwardOpToOwnerThread(rtPtr, ForwardedOutput, &p); + + if (p.base.code != TCL_OK) { + PassReceivedError(rtPtr->chan, &p); + *errorCodePtr = EINVAL; + return 0; + } + + *errorCodePtr = EOK; + res = Tcl_WriteRaw(rtPtr->parent, (char *) p.transform.buf, + p.transform.size); + ckfree(p.transform.buf); + } else +#endif + { + /* ASSERT: rtPtr->method & FLAG(METH_WRITE) */ + /* ASSERT: rtPtr->mode & TCL_WRITABLE */ + + bufObj = Tcl_NewByteArrayObj((unsigned char *) buf, toWrite); + Tcl_IncrRefCount(bufObj); + if (InvokeTclMethod(rtPtr, "write", bufObj, NULL, &resObj) != TCL_OK) { + *errorCodePtr = EINVAL; + Tcl_SetChannelError(rtPtr->chan, resObj); + + Tcl_DecrRefCount(bufObj); + Tcl_DecrRefCount(resObj); /* Remove reference held from invoke */ + return 0; + } + + *errorCodePtr = EOK; + + bytev = Tcl_GetByteArrayFromObj(resObj, &bytec); + res = Tcl_WriteRaw(rtPtr->parent, (char *) bytev, bytec); + + Tcl_DecrRefCount(bufObj); + Tcl_DecrRefCount(resObj); /* Remove reference held from invoke */ + } + + if (res < 0) { + *errorCodePtr = EINVAL; + return 0; + } + + return 1; +} + +static int +TransformDrain( + ReflectedTransform *rtPtr, + int *errorCodePtr) +{ + Tcl_Obj *resObj; + int bytec; /* Number of returned bytes */ + unsigned char *bytev; /* Array of returned bytes */ + + /* + * Are we in the correct thread? + */ + +#ifdef TCL_THREADS + if (rtPtr->thread != Tcl_GetCurrentThread()) { + ForwardParam p; + + ForwardOpToOwnerThread(rtPtr, ForwardedDrain, &p); + + if (p.base.code != TCL_OK) { + PassReceivedError(rtPtr->chan, &p); + *errorCodePtr = EINVAL; + return 0; + } + + *errorCodePtr = EOK; + ResultAdd(&rtPtr->result, UCHARP(p.transform.buf), p.transform.size); + ckfree(p.transform.buf); + } else +#endif + { + if (InvokeTclMethod(rtPtr, "drain", NULL, NULL, &resObj)!=TCL_OK) { + Tcl_SetChannelError(rtPtr->chan, resObj); + Tcl_DecrRefCount(resObj); /* Remove reference held from invoke */ + *errorCodePtr = EINVAL; + return 0; + } + + bytev = Tcl_GetByteArrayFromObj(resObj, &bytec); + ResultAdd(&rtPtr->result, bytev, bytec); + + Tcl_DecrRefCount(resObj); /* Remove reference held from invoke */ + } + + rtPtr->readIsDrained = 1; + return 1; +} + +static int +TransformFlush( + ReflectedTransform *rtPtr, + int *errorCodePtr, + int op) +{ + Tcl_Obj *resObj; + int bytec; /* Number of returned bytes */ + unsigned char *bytev; /* Array of returned bytes */ + int res; + + /* + * Are we in the correct thread? + */ + +#ifdef TCL_THREADS + if (rtPtr->thread != Tcl_GetCurrentThread()) { + ForwardParam p; + + ForwardOpToOwnerThread(rtPtr, ForwardedFlush, &p); + + if (p.base.code != TCL_OK) { + PassReceivedError(rtPtr->chan, &p); + *errorCodePtr = EINVAL; + return 0; + } + + *errorCodePtr = EOK; + if (op == FLUSH_WRITE) { + res = Tcl_WriteRaw(rtPtr->parent, (char *) p.transform.buf, + p.transform.size); + } else { + res = 0; + } + ckfree(p.transform.buf); + } else +#endif + { + if (InvokeTclMethod(rtPtr, "flush", NULL, NULL, &resObj)!=TCL_OK) { + Tcl_SetChannelError(rtPtr->chan, resObj); + Tcl_DecrRefCount(resObj); /* Remove reference held from invoke */ + *errorCodePtr = EINVAL; + return 0; + } + + if (op == FLUSH_WRITE) { + bytev = Tcl_GetByteArrayFromObj(resObj, &bytec); + res = Tcl_WriteRaw(rtPtr->parent, (char *) bytev, bytec); + } else { + res = 0; + } + Tcl_DecrRefCount(resObj); /* Remove reference held from invoke */ + } + + if (res < 0) { + *errorCodePtr = EINVAL; + return 0; + } + + return 1; +} + +static void +TransformClear( + ReflectedTransform *rtPtr) +{ + /* + * Are we in the correct thread? + */ + +#ifdef TCL_THREADS + if (rtPtr->thread != Tcl_GetCurrentThread()) { + ForwardParam p; + + ForwardOpToOwnerThread(rtPtr, ForwardedClear, &p); + return; + } +#endif + + /* ASSERT: rtPtr->method & FLAG(METH_READ) */ + /* ASSERT: rtPtr->mode & TCL_READABLE */ + + (void) InvokeTclMethod(rtPtr, "clear", NULL, NULL, NULL); + + rtPtr->readIsDrained = 0; + ResultClear(&rtPtr->result); +} + +static int +TransformLimit( + ReflectedTransform *rtPtr, + int *errorCodePtr, + int *maxPtr) +{ + Tcl_Obj *resObj; + Tcl_InterpState sr; /* State of handler interp */ + + /* + * Are we in the correct thread? + */ + +#ifdef TCL_THREADS + if (rtPtr->thread != Tcl_GetCurrentThread()) { + ForwardParam p; + + ForwardOpToOwnerThread(rtPtr, ForwardedLimit, &p); + + if (p.base.code != TCL_OK) { + PassReceivedError(rtPtr->chan, &p); + *errorCodePtr = EINVAL; + return 0; + } + + *errorCodePtr = EOK; + *maxPtr = p.limit.max; + return 1; + } +#endif + + /* ASSERT: rtPtr->method & FLAG(METH_WRITE) */ + /* ASSERT: rtPtr->mode & TCL_WRITABLE */ + + if (InvokeTclMethod(rtPtr, "limit?", NULL, NULL, &resObj) != TCL_OK) { + Tcl_SetChannelError(rtPtr->chan, resObj); + Tcl_DecrRefCount(resObj); /* Remove reference held from invoke */ + *errorCodePtr = EINVAL; + return 0; + } + + sr = Tcl_SaveInterpState(rtPtr->interp, 0 /* Dummy */); + + if (Tcl_GetIntFromObj(rtPtr->interp, resObj, maxPtr) != TCL_OK) { + Tcl_DecrRefCount(resObj); /* Remove reference held from invoke */ + Tcl_SetChannelError(rtPtr->chan, MarshallError(rtPtr->interp)); + *errorCodePtr = EINVAL; + + Tcl_RestoreInterpState(rtPtr->interp, sr); + return 0; + } + + Tcl_DecrRefCount(resObj); /* Remove reference held from invoke */ + Tcl_RestoreInterpState(rtPtr->interp, sr); + return 1; +} + +/* DUPLICATE of HaveVersion() in tclIO.c + *---------------------------------------------------------------------- + * + * HaveVersion -- + * + * Return whether a channel type is (at least) of a given version. + * + * Results: + * True if the minimum version is exceeded by the version actually + * present. + * + * Side effects: + * None. + * + *---------------------------------------------------------------------- + */ + +static int +HaveVersion( + const Tcl_ChannelType *chanTypePtr, + Tcl_ChannelTypeVersion minimumVersion) +{ + Tcl_ChannelTypeVersion actualVersion = Tcl_ChannelVersion(chanTypePtr); + + return PTR2INT(actualVersion) >= PTR2INT(minimumVersion); +} + +/* + * Local Variables: + * mode: c + * c-basic-offset: 4 + * fill-column: 78 + * End: + */ |