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Diffstat (limited to 'generic/tclIOGT.c')
| -rw-r--r-- | generic/tclIOGT.c | 1359 |
1 files changed, 1359 insertions, 0 deletions
diff --git a/generic/tclIOGT.c b/generic/tclIOGT.c new file mode 100644 index 0000000..70de14f --- /dev/null +++ b/generic/tclIOGT.c @@ -0,0 +1,1359 @@ +/* + * tclIOGT.c -- + * + * Implements a generic transformation exposing the underlying API + * at the script level. Contributed by Andreas Kupries. + * + * Copyright (c) 2000 Ajuba Solutions + * Copyright (c) 1999-2000 Andreas Kupries (a.kupries@westend.com) + * + * See the file "license.terms" for information on usage and redistribution + * of this file, and for a DISCLAIMER OF ALL WARRANTIES. + * + * CVS: $Id: tclIOGT.c,v 1.2 2000/09/28 06:38:21 hobbs Exp $ + */ + +#include "tclInt.h" +#include "tclPort.h" +#include "tclIO.h" + + +/* + * Forward declarations of internal procedures. + * First the driver procedures of the transformation. + */ + +static int TransformBlockModeProc _ANSI_ARGS_ (( + ClientData instanceData, int mode)); +static int TransformCloseProc _ANSI_ARGS_ (( + ClientData instanceData, Tcl_Interp* interp)); +static int TransformInputProc _ANSI_ARGS_ (( + ClientData instanceData, + char* buf, int toRead, int* errorCodePtr)); +static int TransformOutputProc _ANSI_ARGS_ (( + ClientData instanceData, + char* buf, int toWrite, int* errorCodePtr)); +static int TransformSeekProc _ANSI_ARGS_ (( + ClientData instanceData, long offset, + int mode, int* errorCodePtr)); +static int TransformSetOptionProc _ANSI_ARGS_(( + ClientData instanceData, Tcl_Interp *interp, + char *optionName, char *value)); +static int TransformGetOptionProc _ANSI_ARGS_(( + ClientData instanceData, Tcl_Interp *interp, + char *optionName, Tcl_DString *dsPtr)); +static void TransformWatchProc _ANSI_ARGS_ (( + ClientData instanceData, int mask)); +static int TransformGetFileHandleProc _ANSI_ARGS_ (( + ClientData instanceData, int direction, + ClientData* handlePtr)); +static int TransformNotifyProc _ANSI_ARGS_ (( + ClientData instanceData, int mask)); + +/* + * Forward declarations of internal procedures. + * Secondly the procedures for handling and generating fileeevents. + */ + +static void TransformChannelHandlerTimer _ANSI_ARGS_ (( + ClientData clientData)); + +/* + * Forward declarations of internal procedures. + * Third, helper procedures encapsulating essential tasks. + */ + +typedef struct TransformChannelData TransformChannelData; + +static int ExecuteCallback _ANSI_ARGS_ (( + TransformChannelData* ctrl, Tcl_Interp* interp, + unsigned char* op, unsigned char* buf, + int bufLen, int transmit, int preserve)); + +/* + * Action codes to give to 'ExecuteCallback' (argument 'transmit') + * confering to the procedure what to do with the result of the script + * it calls. + */ + +#define TRANSMIT_DONT (0) /* No transfer to do */ +#define TRANSMIT_DOWN (1) /* Transfer to the underlying channel */ +#define TRANSMIT_SELF (2) /* Transfer into our channel. */ +#define TRANSMIT_IBUF (3) /* Transfer to internal input buffer */ +#define TRANSMIT_NUM (4) /* Transfer number to 'maxRead' */ + +/* + * Codes for 'preserve' of 'ExecuteCallback' + */ + +#define P_PRESERVE (1) +#define P_NO_PRESERVE (0) + +/* + * Strings for the action codes delivered to the script implementing + * a transformation. Argument 'op' of 'ExecuteCallback'. + */ + +#define A_CREATE_WRITE (UCHARP ("create/write")) +#define A_DELETE_WRITE (UCHARP ("delete/write")) +#define A_FLUSH_WRITE (UCHARP ("flush/write")) +#define A_WRITE (UCHARP ("write")) + +#define A_CREATE_READ (UCHARP ("create/read")) +#define A_DELETE_READ (UCHARP ("delete/read")) +#define A_FLUSH_READ (UCHARP ("flush/read")) +#define A_READ (UCHARP ("read")) + +#define A_QUERY_MAXREAD (UCHARP ("query/maxRead")) +#define A_CLEAR_READ (UCHARP ("clear/read")) + +/* + * Management of a simple buffer. + */ + +typedef struct ResultBuffer ResultBuffer; + +static void ResultClear _ANSI_ARGS_ ((ResultBuffer* r)); +static void ResultInit _ANSI_ARGS_ ((ResultBuffer* r)); +static int ResultLength _ANSI_ARGS_ ((ResultBuffer* r)); +static int ResultCopy _ANSI_ARGS_ ((ResultBuffer* r, + unsigned char* buf, int toRead)); +static void ResultAdd _ANSI_ARGS_ ((ResultBuffer* r, + unsigned char* buf, int toWrite)); + +/* + * This structure describes the channel type structure for tcl based + * transformations. + */ + +static Tcl_ChannelType transformChannelType = { + "transform", /* Type name. */ + TCL_CHANNEL_VERSION_2, + TransformCloseProc, /* Close proc. */ + TransformInputProc, /* Input proc. */ + TransformOutputProc, /* Output proc. */ + TransformSeekProc, /* Seek proc. */ + TransformSetOptionProc, /* Set option proc. */ + TransformGetOptionProc, /* Get option proc. */ + TransformWatchProc, /* Initialize notifier. */ + TransformGetFileHandleProc, /* Get OS handles out of channel. */ + NULL, /* close2proc */ + TransformBlockModeProc, /* Set blocking/nonblocking mode.*/ + NULL, /* Flush proc. */ + TransformNotifyProc, /* Handling of events bubbling up */ +}; + +/* + * Possible values for 'flags' field in control structure, see below. + */ + +#define CHANNEL_ASYNC (1<<0) /* non-blocking mode */ + +/* + * Definition of the structure containing the information about the + * internal input buffer. + */ + +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 */ +}; + +/* + * Additional bytes to allocate during buffer expansion + */ + +#define INCREMENT (512) + +/* + * Number of milliseconds to wait before firing an event to flush + * out information waiting in buffers (fileevent support). + */ + +#define DELAY (5) + +/* + * Convenience macro to make some casts easier to use. + */ + +#define UCHARP(x) ((unsigned char*) (x)) +#define NO_INTERP ((Tcl_Interp*) NULL) + +/* + * Definition of a structure used by all transformations generated here to + * maintain their local state. + */ + +struct TransformChannelData { + + /* + * General section. Data to integrate the transformation into the channel + * system. + */ + + Tcl_Channel self; /* Our own Channel handle */ + int readIsFlushed; /* Flag to note wether in.flushProc was called or not + */ + int flags; /* Currently CHANNEL_ASYNC or zero */ + int watchMask; /* Current watch/event/interest mask */ + int mode; /* mode of parent channel, OR'ed combination of + * TCL_READABLE, TCL_WRITABLE */ + Tcl_TimerToken timer; /* Timer for automatic flushing of information + * sitting in an internal buffer. Required for full + * fileevent support */ + /* + * Transformation specific data. + */ + + int maxRead; /* Maximum allowed number of bytes to read, as + * given to us by the tcl script implementing the + * transformation. */ + Tcl_Interp* interp; /* Reference to the interpreter which created the + * transformation. Used to execute the code + * below. */ + Tcl_Obj* command; /* Tcl code to execute for a buffer */ + ResultBuffer result; /* Internal buffer used to store the result of a + * transformation of incoming data. Additionally + * serves as buffer of all data not yet consumed by + * the reader. */ +}; + + +/* + *---------------------------------------------------------------------- + * + * TclChannelTransform -- + * + * Implements the Tcl "testchannel transform" debugging command. + * This is part of the testing environment. This sets up a tcl + * script (cmdObjPtr) to be used as a transform on the channel. + * + * Results: + * A standard Tcl result. + * + * Side effects: + * None. + * + *---------------------------------------------------------------------- + */ + + /* ARGSUSED */ +int +TclChannelTransform(interp, chan, cmdObjPtr) + Tcl_Interp *interp; /* Interpreter for result. */ + Tcl_Channel chan; /* Channel to transform. */ + Tcl_Obj *cmdObjPtr; /* Script to use for transform. */ +{ + Channel *chanPtr; /* The actual channel. */ + ChannelState *statePtr; /* state info for channel */ + int mode; /* rw mode of the channel */ + TransformChannelData *dataPtr; + int res; + Tcl_DString ds; + + if (chan == (Tcl_Channel) NULL) { + return TCL_ERROR; + } + chanPtr = (Channel *) chan; + statePtr = chanPtr->state; + chanPtr = statePtr->topChanPtr; + chan = (Tcl_Channel) chanPtr; + mode = (statePtr->flags & (TCL_READABLE|TCL_WRITABLE)); + + /* + * Now initialize the transformation state and stack it upon the + * specified channel. One of the necessary things to do is to + * retrieve the blocking regime of the underlying channel and to + * use the same for us too. + */ + + dataPtr = (TransformChannelData*) ckalloc(sizeof(TransformChannelData)); + + Tcl_DStringInit (&ds); + Tcl_GetChannelOption(interp, chan, "-blocking", &ds); + + dataPtr->readIsFlushed = 0; + dataPtr->flags = 0; + + if (ds.string[0] == '0') { + dataPtr->flags |= CHANNEL_ASYNC; + } + + Tcl_DStringFree (&ds); + + dataPtr->self = chan; + dataPtr->watchMask = 0; + dataPtr->mode = mode; + dataPtr->timer = (Tcl_TimerToken) NULL; + dataPtr->maxRead = 4096; /* Initial value not relevant */ + dataPtr->interp = interp; + dataPtr->command = cmdObjPtr; + + Tcl_IncrRefCount(dataPtr->command); + + ResultInit(&dataPtr->result); + + dataPtr->self = Tcl_StackChannel(interp, &transformChannelType, + (ClientData) dataPtr, mode, chan); + if (dataPtr->self == (Tcl_Channel) NULL) { + Tcl_AppendResult(interp, "\nfailed to stack channel \"", + Tcl_GetChannelName(chan), "\"", (char *) NULL); + + Tcl_DecrRefCount(dataPtr->command); + ResultClear(&dataPtr->result); + ckfree((VOID *) dataPtr); + return TCL_ERROR; + } + + /* + * At last initialize the transformation at the script level. + */ + + if (dataPtr->mode & TCL_WRITABLE) { + res = ExecuteCallback (dataPtr, NO_INTERP, A_CREATE_WRITE, + NULL, 0, TRANSMIT_DONT, P_NO_PRESERVE); + + if (res != TCL_OK) { + Tcl_UnstackChannel(interp, chan); + return TCL_ERROR; + } + } + + if (dataPtr->mode & TCL_READABLE) { + res = ExecuteCallback (dataPtr, NO_INTERP, A_CREATE_READ, + NULL, 0, TRANSMIT_DONT, P_NO_PRESERVE); + + if (res != TCL_OK) { + ExecuteCallback (dataPtr, NO_INTERP, A_DELETE_WRITE, + NULL, 0, TRANSMIT_DONT, P_NO_PRESERVE); + + Tcl_UnstackChannel(interp, chan); + return TCL_ERROR; + } + } + + return TCL_OK; +} + +/* + *------------------------------------------------------* + * + * ExecuteCallback -- + * + * Executes the defined callback for buffer and + * operation. + * + * Sideeffects: + * As of the executed tcl script. + * + * Result: + * A standard TCL error code. In case of an + * error a message is left in the result area + * of the specified interpreter. + * + *------------------------------------------------------* + */ + +static int +ExecuteCallback (dataPtr, interp, op, buf, bufLen, transmit, preserve) + TransformChannelData* dataPtr; /* Transformation with the callback */ + Tcl_Interp* interp; /* Current interpreter, possibly NULL */ + unsigned char* op; /* Operation invoking the callback */ + unsigned char* buf; /* Buffer to give to the script. */ + int bufLen; /* Ands its length */ + int transmit; /* Flag, determines whether the result + * of the callback is sent to the + * underlying channel or not. */ + int preserve; /* Flag. If true the procedure will + * preserver the result state of all + * accessed interpreters. */ +{ + /* + * Step 1, create the complete command to execute. Do this by appending + * operation and buffer to operate upon to a copy of the callback + * definition. We *cannot* create a list containing 3 objects and then use + * 'Tcl_EvalObjv', because the command may contain additional prefixed + * arguments. Feather's curried commands would come in handy here. + */ + + Tcl_Obj* resObj; /* See below, switch (transmit) */ + int resLen; + unsigned char* resBuf; + Tcl_SavedResult ciSave; + + int res = TCL_OK; + Tcl_Obj* command = Tcl_DuplicateObj (dataPtr->command); + Tcl_Obj* temp; + + + if (preserve) { + Tcl_SaveResult (dataPtr->interp, &ciSave); + } + + if (command == (Tcl_Obj*) NULL) { + /* Memory allocation problem */ + res = TCL_ERROR; + goto cleanup; + } + + Tcl_IncrRefCount(command); + + temp = Tcl_NewStringObj((char*) op, -1); + + if (temp == (Tcl_Obj*) NULL) { + /* Memory allocation problem */ + res = TCL_ERROR; + goto cleanup; + } + + res = Tcl_ListObjAppendElement(dataPtr->interp, command, temp); + + if (res != TCL_OK) + goto cleanup; + + /* + * Use a byte-array to prevent the misinterpretation of binary data + * coming through as UTF while at the tcl level. + */ + + temp = Tcl_NewByteArrayObj(buf, bufLen); + + if (temp == (Tcl_Obj*) NULL) { + /* Memory allocation problem */ + res = TCL_ERROR; + goto cleanup; + } + + res = Tcl_ListObjAppendElement (dataPtr->interp, command, temp); + + if (res != TCL_OK) + goto cleanup; + + /* + * Step 2, execute the command at the global level of the interpreter + * used to create the transformation. Destroy the command afterward. + * If an error occured and the current interpreter is defined and not + * equal to the interpreter for the callback, then copy the error + * message into current interpreter. Don't copy if in preservation mode. + */ + + res = Tcl_GlobalEvalObj (dataPtr->interp, command); + Tcl_DecrRefCount (command); + command = (Tcl_Obj*) NULL; + + if ((res != TCL_OK) && (interp != NO_INTERP) && + (dataPtr->interp != interp) && !preserve) { + Tcl_SetObjResult(interp, Tcl_GetObjResult(dataPtr->interp)); + return res; + } + + /* + * Step 3, transmit a possible conversion result to the underlying + * channel, or ourselves. + */ + + switch (transmit) { + case TRANSMIT_DONT: + /* nothing to do */ + break; + + case TRANSMIT_DOWN: + resObj = Tcl_GetObjResult(dataPtr->interp); + resBuf = (unsigned char*) Tcl_GetByteArrayFromObj(resObj, &resLen); + Tcl_WriteRaw(Tcl_GetStackedChannel(dataPtr->self), + (char*) resBuf, resLen); + break; + + case TRANSMIT_SELF: + resObj = Tcl_GetObjResult (dataPtr->interp); + resBuf = (unsigned char*) Tcl_GetByteArrayFromObj(resObj, &resLen); + Tcl_WriteRaw(dataPtr->self, (char*) resBuf, resLen); + break; + + case TRANSMIT_IBUF: + resObj = Tcl_GetObjResult (dataPtr->interp); + resBuf = (unsigned char*) Tcl_GetByteArrayFromObj(resObj, &resLen); + ResultAdd(&dataPtr->result, resBuf, resLen); + break; + + case TRANSMIT_NUM: + /* Interpret result as integer number */ + resObj = Tcl_GetObjResult (dataPtr->interp); + Tcl_GetIntFromObj(dataPtr->interp, resObj, &dataPtr->maxRead); + break; + } + + Tcl_ResetResult(dataPtr->interp); + + if (preserve) { + Tcl_RestoreResult(dataPtr->interp, &ciSave); + } + + return res; + + cleanup: + if (preserve) { + Tcl_RestoreResult(dataPtr->interp, &ciSave); + } + + if (command != (Tcl_Obj*) NULL) { + Tcl_DecrRefCount(command); + } + + return res; +} + +/* + *------------------------------------------------------* + * + * TransformBlockModeProc -- + * + * Trap handler. Called by the generic IO system + * during option processing to change the blocking + * mode of the channel. + * + * Sideeffects: + * Forwards the request to the underlying + * channel. + * + * Result: + * 0 if successful, errno when failed. + * + *------------------------------------------------------* + */ + +static int +TransformBlockModeProc (instanceData, mode) + ClientData instanceData; /* State of transformation */ + int mode; /* New blocking mode */ +{ + TransformChannelData* dataPtr = (TransformChannelData*) instanceData; + + if (mode == TCL_MODE_NONBLOCKING) { + dataPtr->flags |= CHANNEL_ASYNC; + } else { + dataPtr->flags &= ~(CHANNEL_ASYNC); + } + return 0; +} + +/* + *------------------------------------------------------* + * + * TransformCloseProc -- + * + * Trap handler. Called by the generic IO system + * during destruction of the transformation channel. + * + * Sideeffects: + * Releases the memory allocated in + * 'Tcl_TransformObjCmd'. + * + * Result: + * None. + * + *------------------------------------------------------* + */ + +static int +TransformCloseProc (instanceData, interp) + ClientData instanceData; + Tcl_Interp* interp; +{ + TransformChannelData* dataPtr = (TransformChannelData*) instanceData; + + /* + * Important: In this procedure 'dataPtr->self' already points to + * the underlying channel. + */ + + /* + * There is no need to cancel an existing channel handler, this is already + * done. Either by 'Tcl_UnstackChannel' or by the general cleanup in + * 'Tcl_Close'. + * + * But we have to cancel an active timer to prevent it from firing on the + * removed channel. + */ + + if (dataPtr->timer != (Tcl_TimerToken) NULL) { + Tcl_DeleteTimerHandler (dataPtr->timer); + dataPtr->timer = (Tcl_TimerToken) NULL; + } + + /* + * Now flush data waiting in internal buffers to output and input. The + * input must be done despite the fact that there is no real receiver + * for it anymore. But the scripts might have sideeffects other parts + * of the system rely on (f.e. signaling the close to interested parties). + */ + + if (dataPtr->mode & TCL_WRITABLE) { + ExecuteCallback (dataPtr, interp, A_FLUSH_WRITE, + NULL, 0, TRANSMIT_DOWN, 1); + } + + if ((dataPtr->mode & TCL_READABLE) && !dataPtr->readIsFlushed) { + dataPtr->readIsFlushed = 1; + ExecuteCallback (dataPtr, interp, A_FLUSH_READ, + NULL, 0, TRANSMIT_IBUF, 1); + } + + if (dataPtr->mode & TCL_WRITABLE) { + ExecuteCallback (dataPtr, interp, A_DELETE_WRITE, + NULL, 0, TRANSMIT_DONT, 1); + } + + if (dataPtr->mode & TCL_READABLE) { + ExecuteCallback (dataPtr, interp, A_DELETE_READ, + NULL, 0, TRANSMIT_DONT, 1); + } + + /* + * General cleanup + */ + + ResultClear(&dataPtr->result); + Tcl_DecrRefCount(dataPtr->command); + ckfree((VOID*) dataPtr); + + return TCL_OK; +} + +/* + *------------------------------------------------------* + * + * TransformInputProc -- + * + * Called by the generic IO system to convert read data. + * + * Sideeffects: + * As defined by the conversion. + * + * Result: + * A transformed buffer. + * + *------------------------------------------------------* + */ + +static int +TransformInputProc (instanceData, buf, toRead, errorCodePtr) + ClientData instanceData; + char* buf; + int toRead; + int* errorCodePtr; +{ + TransformChannelData* dataPtr = (TransformChannelData*) instanceData; + int gotBytes, read, res, copied; + Tcl_Channel downChan; + + /* should assert (dataPtr->mode & TCL_READABLE) */ + + if (toRead == 0) { + /* Catch a no-op. + */ + return 0; + } + + gotBytes = 0; + downChan = Tcl_GetStackedChannel(dataPtr->self); + + while (toRead > 0) { + /* + * Loop until the request is satisfied (or no data is available from + * below, possibly EOF). + */ + + copied = ResultCopy (&dataPtr->result, UCHARP (buf), toRead); + + toRead -= copied; + buf += copied; + gotBytes += copied; + + if (toRead == 0) { + /* The request was completely satisfied from our buffers. + * We can break out of the loop and return to the caller. + */ + return gotBytes; + } + + /* + * Length (dataPtr->result) == 0, toRead > 0 here . Use the incoming + * 'buf'! as target to store the intermediary information read + * from the underlying channel. + * + * Ask the tcl level 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', either through counting bytes, + * or by pattern matching. + */ + + ExecuteCallback (dataPtr, NO_INTERP, A_QUERY_MAXREAD, + NULL, 0, TRANSMIT_NUM /* -> maxRead */, 1); + + if (dataPtr->maxRead >= 0) { + if (dataPtr->maxRead < toRead) { + toRead = dataPtr->maxRead; + } + } /* else: 'maxRead < 0' == Accept the current value of toRead */ + + if (toRead <= 0) { + return gotBytes; + } + + read = Tcl_ReadRaw(downChan, buf, toRead); + + if (read < 0) { + /* Report errors to caller. EAGAIN is a special situation. + * If we had some data before we report that instead of the + * request to re-try. + */ + + if ((Tcl_GetErrno() == EAGAIN) && (gotBytes > 0)) { + return gotBytes; + } + + *errorCodePtr = Tcl_GetErrno(); + return -1; + } + + if (read == 0) { + /* + * Check wether we hit on EOF in the underlying channel 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 (downChan)) { + if ((gotBytes == 0) && (dataPtr->flags & CHANNEL_ASYNC)) { + *errorCodePtr = EWOULDBLOCK; + return -1; + } else { + return gotBytes; + } + } else { + if (dataPtr->readIsFlushed) { + /* Already flushed, nothing to do anymore + */ + return gotBytes; + } + + dataPtr->readIsFlushed = 1; + + ExecuteCallback (dataPtr, NO_INTERP, A_FLUSH_READ, + NULL, 0, TRANSMIT_IBUF, P_PRESERVE); + + if (ResultLength (&dataPtr->result) == 0) { + /* we had nothing to flush */ + return gotBytes; + } + + continue; /* at: while (toRead > 0) */ + } + } /* read == 0 */ + + /* Transform the read chunk and add the result to our + * read buffer (dataPtr->result) + */ + + res = ExecuteCallback (dataPtr, NO_INTERP, A_READ, + UCHARP (buf), read, TRANSMIT_IBUF, + P_PRESERVE); + + if (res != TCL_OK) { + *errorCodePtr = EINVAL; + return -1; + } + } /* while toRead > 0 */ + + return gotBytes; +} + +/* + *------------------------------------------------------* + * + * TransformOutputProc -- + * + * Called by the generic IO system to convert data + * waiting to be written. + * + * Sideeffects: + * As defined by the transformation. + * + * Result: + * A transformed buffer. + * + *------------------------------------------------------* + */ + +static int +TransformOutputProc (instanceData, buf, toWrite, errorCodePtr) + ClientData instanceData; + char* buf; + int toWrite; + int* errorCodePtr; +{ + TransformChannelData* dataPtr = (TransformChannelData*) instanceData; + int res; + + /* should assert (dataPtr->mode & TCL_WRITABLE) */ + + if (toWrite == 0) { + /* Catch a no-op. + */ + return 0; + } + + res = ExecuteCallback (dataPtr, NO_INTERP, A_WRITE, + UCHARP (buf), toWrite, + TRANSMIT_DOWN, P_NO_PRESERVE); + + if (res != TCL_OK) { + *errorCodePtr = EINVAL; + return -1; + } + + return toWrite; +} + +/* + *------------------------------------------------------* + * + * TransformSeekProc -- + * + * This procedure is called by the generic IO level + * to move the access point in a channel. + * + * Sideeffects: + * Moves the location at which the channel + * will be accessed in future operations. + * Flushes all transformation buffers, then + * forwards it to the underlying channel. + * + * Result: + * -1 if failed, the new position if + * successful. An output argument contains + * the POSIX error code if an error + * occurred, or zero. + * + *------------------------------------------------------* + */ + +static int +TransformSeekProc (instanceData, offset, mode, errorCodePtr) + ClientData instanceData; /* The channel to manipulate */ + long offset; /* Size of movement. */ + int mode; /* How to move */ + int* errorCodePtr; /* Location of error flag. */ +{ + int result; + TransformChannelData* dataPtr = (TransformChannelData*) instanceData; + Tcl_Channel parent = Tcl_GetStackedChannel(dataPtr->self); + Tcl_ChannelType* parentType = Tcl_GetChannelType(parent); + Tcl_DriverSeekProc* parentSeekProc = Tcl_ChannelSeekProc(parentType); + + if ((offset == 0) && (mode == SEEK_CUR)) { + /* This is no seek but a request to tell the caller the current + * location. Simply pass the request down. + */ + + result = (*parentSeekProc) (Tcl_GetChannelInstanceData(parent), + offset, mode, errorCodePtr); + return result; + } + + /* + * It is a real request to change the position. Flush all data waiting + * for output and discard everything in the input buffers. Then pass + * the request down, unchanged. + */ + + if (dataPtr->mode & TCL_WRITABLE) { + ExecuteCallback (dataPtr, NO_INTERP, A_FLUSH_WRITE, + NULL, 0, TRANSMIT_DOWN, P_NO_PRESERVE); + } + + if (dataPtr->mode & TCL_READABLE) { + ExecuteCallback (dataPtr, NO_INTERP, A_CLEAR_READ, + NULL, 0, TRANSMIT_DONT, P_NO_PRESERVE); + ResultClear(&dataPtr->result); + dataPtr->readIsFlushed = 0; + } + + result = (*parentSeekProc) (Tcl_GetChannelInstanceData(parent), + offset, mode, errorCodePtr); + return result; +} + +/* + *------------------------------------------------------* + * + * TransformSetOptionProc -- + * + * Called by generic layer to handle the reconfi- + * guration of channel specific options. As this + * channel type does not have such, it simply passes + * all requests downstream. + * + * Sideeffects: + * As defined by the channel downstream. + * + * Result: + * A standard TCL error code. + * + *------------------------------------------------------* + */ + +static int +TransformSetOptionProc (instanceData, interp, optionName, value) + ClientData instanceData; + Tcl_Interp *interp; + char *optionName; + char *value; +{ + TransformChannelData* dataPtr = (TransformChannelData*) instanceData; + Tcl_Channel downChan = Tcl_GetStackedChannel(dataPtr->self); + Tcl_DriverSetOptionProc *setOptionProc; + + setOptionProc = Tcl_ChannelSetOptionProc(Tcl_GetChannelType(downChan)); + if (setOptionProc != NULL) { + return (*setOptionProc)(Tcl_GetChannelInstanceData(downChan), + interp, optionName, value); + } + return TCL_ERROR; +} + +/* + *------------------------------------------------------* + * + * TransformGetOptionProc -- + * + * Called by generic layer to handle requests for + * the values of channel specific options. As this + * channel type does not have such, it simply passes + * all requests downstream. + * + * Sideeffects: + * As defined by the channel downstream. + * + * Result: + * A standard TCL error code. + * + *------------------------------------------------------* + */ + +static int +TransformGetOptionProc (instanceData, interp, optionName, dsPtr) + ClientData instanceData; + Tcl_Interp* interp; + char* optionName; + Tcl_DString* dsPtr; +{ + TransformChannelData* dataPtr = (TransformChannelData*) instanceData; + Tcl_Channel downChan = Tcl_GetStackedChannel(dataPtr->self); + Tcl_DriverGetOptionProc *getOptionProc; + + getOptionProc = Tcl_ChannelGetOptionProc(Tcl_GetChannelType(downChan)); + if (getOptionProc != NULL) { + return (*getOptionProc)(Tcl_GetChannelInstanceData(downChan), + interp, optionName, dsPtr); + } else if (optionName == (char*) NULL) { + /* + * Request is query for all options, this is ok. + */ + return TCL_OK; + } + /* + * Request for a specific option has to fail, we don't have any. + */ + return TCL_ERROR; +} + +/* + *------------------------------------------------------* + * + * TransformWatchProc -- + * + * Initialize the notifier to watch for events from + * this channel. + * + * Sideeffects: + * Sets up the notifier so that a future + * event on the channel will be seen by Tcl. + * + * Result: + * None. + * + *------------------------------------------------------* + */ + /* ARGSUSED */ +static void +TransformWatchProc (instanceData, mask) + ClientData instanceData; /* Channel to watch */ + int mask; /* Events of interest */ +{ + /* The caller expressed interest in events occuring for this + * channel. We are forwarding the call to the underlying + * channel now. + */ + + TransformChannelData* dataPtr = (TransformChannelData*) instanceData; + Tcl_Channel downChan; + + dataPtr->watchMask = mask; + + /* No channel handlers any more. We will be notified automatically + * about events on the channel below via a call to our + * 'TransformNotifyProc'. But we have to pass the interest down now. + * We are allowed to add additional 'interest' to the mask if we want + * to. But this transformation has no such interest. It just passes + * the request down, unchanged. + */ + + downChan = Tcl_GetStackedChannel(dataPtr->self); + + (Tcl_GetChannelType(downChan)) + ->watchProc(Tcl_GetChannelInstanceData(downChan), mask); + + /* + * Management of the internal timer. + */ + + if ((dataPtr->timer != (Tcl_TimerToken) NULL) && + (!(mask & TCL_READABLE) || (ResultLength(&dataPtr->result) == 0))) { + + /* A pending timer exists, but either is there no (more) + * interest in the events it generates or nothing is availablee + * for reading, so remove it. + */ + + Tcl_DeleteTimerHandler (dataPtr->timer); + dataPtr->timer = (Tcl_TimerToken) NULL; + } + + if ((dataPtr->timer == (Tcl_TimerToken) NULL) && + (mask & TCL_READABLE) && (ResultLength (&dataPtr->result) > 0)) { + + /* There is no pending timer, but there is interest in readable + * events and we actually have data waiting, so generate a timer + * to flush that. + */ + + dataPtr->timer = Tcl_CreateTimerHandler (DELAY, + TransformChannelHandlerTimer, (ClientData) dataPtr); + } +} + +/* + *------------------------------------------------------* + * + * TransformGetFileHandleProc -- + * + * Called from Tcl_GetChannelHandle to retrieve + * OS specific file handle from inside this channel. + * + * Sideeffects: + * None. + * + * Result: + * The appropriate Tcl_File or NULL if not + * present. + * + *------------------------------------------------------* + */ +static int +TransformGetFileHandleProc (instanceData, direction, handlePtr) + ClientData instanceData; /* Channel to query */ + int direction; /* Direction of interest */ + ClientData* handlePtr; /* Place to store the handle into */ +{ + /* + * Return the handle belonging to parent channel. + * IOW, pass the request down and the result up. + */ + + TransformChannelData* dataPtr = (TransformChannelData*) instanceData; + + return Tcl_GetChannelHandle(Tcl_GetStackedChannel(dataPtr->self), + direction, handlePtr); +} + +/* + *------------------------------------------------------* + * + * TransformNotifyProc -- + * + * ------------------------------------------------* + * Handler called by Tcl to inform us of activity + * on the underlying channel. + * ------------------------------------------------* + * + * Sideeffects: + * May process the incoming event by itself. + * + * Result: + * None. + * + *------------------------------------------------------* + */ + +static int +TransformNotifyProc (clientData, mask) + ClientData clientData; /* The state of the notified transformation */ + int mask; /* The mask of occuring events */ +{ + TransformChannelData* dataPtr = (TransformChannelData*) clientData; + + /* + * An event occured in the underlying channel. This + * transformation doesn't process such events thus returns the + * incoming mask unchanged. + */ + + if (dataPtr->timer != (Tcl_TimerToken) NULL) { + /* + * Delete an existing 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 TransformWatchProc). + */ + + Tcl_DeleteTimerHandler (dataPtr->timer); + dataPtr->timer = (Tcl_TimerToken) NULL; + } + + return mask; +} + +/* + *------------------------------------------------------* + * + * TransformChannelHandlerTimer -- + * + * Called by the notifier (-> timer) to flush out + * information waiting in the input buffer. + * + * Sideeffects: + * As of 'Tcl_NotifyChannel'. + * + * Result: + * None. + * + *------------------------------------------------------* + */ + +static void +TransformChannelHandlerTimer (clientData) + ClientData clientData; /* Transformation to query */ +{ + TransformChannelData* dataPtr = (TransformChannelData*) clientData; + + dataPtr->timer = (Tcl_TimerToken) NULL; + + if (!(dataPtr->watchMask & TCL_READABLE) || + (ResultLength (&dataPtr->result) == 0)) { + /* The timer fired, but either is there no (more) + * interest in the events it generates or nothing is available + * for reading, so ignore it and don't recreate it. + */ + + return; + } + + Tcl_NotifyChannel(dataPtr->self, TCL_READABLE); +} + +/* + *------------------------------------------------------* + * + * ResultClear -- + * + * Deallocates any memory allocated by 'ResultAdd'. + * + * Sideeffects: + * See above. + * + * Result: + * None. + * + *------------------------------------------------------* + */ + +static void +ResultClear (r) + ResultBuffer* r; /* Reference to the buffer to clear out */ +{ + r->used = 0; + + if (r->allocated) { + ckfree((char*) r->buf); + r->buf = UCHARP (NULL); + r->allocated = 0; + } +} + +/* + *------------------------------------------------------* + * + * ResultInit -- + * + * Initializes the specified buffer structure. The + * structure will contain valid information for an + * emtpy buffer. + * + * Sideeffects: + * See above. + * + * Result: + * None. + * + *------------------------------------------------------* + */ + +static void +ResultInit (r) + ResultBuffer* r; /* Reference to the structure to initialize */ +{ + r->used = 0; + r->allocated = 0; + r->buf = UCHARP (NULL); +} + +/* + *------------------------------------------------------* + * + * ResultLength -- + * + * Returns the number of bytes stored in the buffer. + * + * Sideeffects: + * None. + * + * Result: + * An integer, see above too. + * + *------------------------------------------------------* + */ + +static int +ResultLength (r) + ResultBuffer* r; /* The structure to query */ +{ + return r->used; +} + +/* + *------------------------------------------------------* + * + * 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. + * + * Sideeffects: + * See above. + * + * Result: + * The number of actually copied bytes, + * possibly less than 'toRead'. + * + *------------------------------------------------------* + */ + +static int +ResultCopy (r, buf, toRead) + ResultBuffer* r; /* The buffer to read from */ + unsigned char* buf; /* The buffer to copy into */ + int toRead; /* Number of requested bytes */ +{ + if (r->used == 0) { + /* Nothing to copy in the case of an empty buffer. + */ + + return 0; + } + + if (r->used == toRead) { + /* We have just enough. Copy everything to the caller. + */ + + memcpy ((VOID*) buf, (VOID*) r->buf, (size_t) toRead); + r->used = 0; + return toRead; + } + + if (r->used > toRead) { + /* The internal buffer contains more than requested. + * Copy the requested subset to the caller, and shift + * the remaining bytes down. + */ + + memcpy ((VOID*) buf, (VOID*) r->buf, (size_t) toRead); + memmove ((VOID*) r->buf, (VOID*) (r->buf + toRead), + (size_t) r->used - toRead); + + r->used -= toRead; + return toRead; + } + + /* There is not enough in the buffer to satisfy the caller, so + * take everything. + */ + + memcpy((VOID*) buf, (VOID*) r->buf, (size_t) r->used); + toRead = r->used; + r->used = 0; + return toRead; +} + +/* + *------------------------------------------------------* + * + * ResultAdd -- + * + * Adds the bytes in the specified array to the + * buffer, by appending it. + * + * Sideeffects: + * See above. + * + * Result: + * None. + * + *------------------------------------------------------* + */ + +static void +ResultAdd (r, buf, toWrite) + ResultBuffer* r; /* The buffer to extend */ + unsigned char* buf; /* The buffer to read from */ + int toWrite; /* The number of bytes in 'buf' */ +{ + if ((r->used + toWrite) > r->allocated) { + /* Extension of the internal buffer is required. + */ + + if (r->allocated == 0) { + r->allocated = toWrite + INCREMENT; + r->buf = UCHARP (ckalloc((unsigned) r->allocated)); + } else { + r->allocated += toWrite + INCREMENT; + r->buf = UCHARP (ckrealloc((char*) r->buf, + (unsigned) r->allocated)); + } + } + + /* now copy data */ + memcpy(r->buf + r->used, buf, (size_t) toWrite); + r->used += toWrite; +} |