From 78bbbde35c3f53764827e54afe963af4ea244aa4 Mon Sep 17 00:00:00 2001 From: dkf Date: Thu, 24 May 2012 09:54:19 +0000 Subject: minor: Cleaning up code, adding comments. --- generic/tclZlib.c | 305 +++++++++++++++++++++++++++++++++--------------------- 1 file changed, 187 insertions(+), 118 deletions(-) diff --git a/generic/tclZlib.c b/generic/tclZlib.c index 0c38602..d4019fc 100644 --- a/generic/tclZlib.c +++ b/generic/tclZlib.c @@ -91,7 +91,7 @@ typedef struct { GzipHeader outHeader; /* Header to write to an output stream, when * compressing a gzip stream. */ Tcl_TimerToken timer; /* Timer used for keeping events fresh. */ - Tcl_DString result; /* Buffer for decompression results. */ + Tcl_DString decompressed; /* Buffer for decompression results. */ } ZlibChannelData; /* @@ -114,10 +114,10 @@ typedef struct { #define DEFAULT_BUFFER_SIZE 4096 /* - * Convenience macro to make some casts easier to use. + * Time to wait before delivering a timer event. */ -#define UCHARP(x) ((unsigned char *) (x)) +#define TRANSFORM_TIMEOUT 0 /* * Prototypes for private procedures defined later in this file: @@ -128,7 +128,7 @@ static Tcl_DriverBlockModeProc ZlibTransformBlockMode; static Tcl_DriverCloseProc ZlibTransformClose; static Tcl_DriverGetHandleProc ZlibTransformGetHandle; static Tcl_DriverGetOptionProc ZlibTransformGetOption; -static Tcl_DriverHandlerProc ZlibTransformHandler; +static Tcl_DriverHandlerProc ZlibTransformEventHandler; static Tcl_DriverInputProc ZlibTransformInput; static Tcl_DriverOutputProc ZlibTransformOutput; static Tcl_DriverSetOptionProc ZlibTransformSetOption; @@ -140,7 +140,7 @@ static void ConvertError(Tcl_Interp *interp, int code); static void ExtractHeader(gz_header *headerPtr, Tcl_Obj *dictObj); static int GenerateHeader(Tcl_Interp *interp, Tcl_Obj *dictObj, GzipHeader *headerPtr, int *extraSizePtr); -static int ResultCopy(Tcl_DString *r, unsigned char *buf, +static inline int ResultCopy(ZlibChannelData *cd, char *buf, int toRead); static int ResultGenerate(ZlibChannelData *cd, int n, int flush, int *errorCodePtr); @@ -148,9 +148,8 @@ static Tcl_Channel ZlibStackChannelTransform(Tcl_Interp *interp, int mode, int format, int level, Tcl_Channel channel, Tcl_Obj *gzipHeaderDictPtr); static void ZlibStreamCleanup(ZlibStreamHandle *zshPtr); -static void ZlibTransformTimerKill(ZlibChannelData *cd); +static inline void ZlibTransformEventTimerKill(ZlibChannelData *cd); static void ZlibTransformTimerRun(ClientData clientData); -static void ZlibTransformTimerSetup(ZlibChannelData *cd); /* * Type of zlib-based compressing and decompressing channels. @@ -170,7 +169,7 @@ static const Tcl_ChannelType zlibChannelType = { NULL, /* close2Proc */ ZlibTransformBlockMode, NULL, /* flushProc */ - ZlibTransformHandler, + ZlibTransformEventHandler, NULL, /* wideSeekProc */ NULL, NULL @@ -2264,6 +2263,12 @@ ZlibStreamCmd( *---------------------------------------------------------------------- * Set of functions to support channel stacking. *---------------------------------------------------------------------- + * + * ZlibTransformClose -- + * + * How to shut down a stacked compressing/decompressing transform. + * + *---------------------------------------------------------------------- */ static int @@ -2278,7 +2283,7 @@ ZlibTransformClose( * Delete the support timer. */ - ZlibTransformTimerKill(cd); + ZlibTransformEventTimerKill(cd); /* * Flush any data waiting to be compressed. @@ -2325,7 +2330,7 @@ ZlibTransformClose( * Release all memory. */ - Tcl_DStringFree (&cd->result); + Tcl_DStringFree(&cd->decompressed); if (cd->inBuffer) { ckfree(cd->inBuffer); @@ -2338,6 +2343,16 @@ ZlibTransformClose( ckfree(cd); return result; } + +/* + *---------------------------------------------------------------------- + * + * ZlibTransformInput -- + * + * Reader filter that does decompression. + * + *---------------------------------------------------------------------- + */ static int ZlibTransformInput( @@ -2363,13 +2378,13 @@ ZlibTransformInput( * below, possibly EOF). */ - copied = ResultCopy(&cd->result, UCHARP(buf), toRead); + copied = ResultCopy(cd, buf, toRead); toRead -= copied; buf += copied; gotBytes += copied; if (toRead == 0) { - goto stop; + return gotBytes; } /* @@ -2378,7 +2393,7 @@ ZlibTransformInput( * transform them for delivery. We may not get what we want (full EOF * or temporarily out of data). * - * Length (cd->result) == 0, toRead > 0 here. + * Length (cd->decompressed) == 0, toRead > 0 here. * * The zlib transform allows us to read at most one character from the * underlying channel to properly identify Z_STREAM_END without @@ -2387,6 +2402,16 @@ ZlibTransformInput( readBytes = Tcl_ReadRaw(cd->parent, cd->inBuffer, 1); + /* + * Three cases here: + * 1. Got some data from the underlying channel (readBytes > 0) so + * it should be fed through the decompression engine. + * 2. Got an error (readBytes < 0) which we should report up except + * for the case where we can convert it to a short read. + * 3. Got an end-of-data from EOF or blocking (readBytes == 0). If + * it is EOF, try flushing the data out of the decompressor. + */ + if (readBytes < 0) { /* * Report errors to caller. The state of the seek system is @@ -2399,16 +2424,14 @@ ZlibTransformInput( * we report that instead of the request to re-try. */ - goto stop; + return gotBytes; } *errorCodePtr = Tcl_GetErrno(); - goto error; - } - - if (readBytes == 0) { + return -1; + } else if (readBytes == 0) { /* - * Check wether we hit on EOF in 'parent' or not. If not + * 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 @@ -2424,56 +2447,61 @@ ZlibTransformInput( if ((gotBytes == 0) && (cd->flags & ASYNC)) { *errorCodePtr = EWOULDBLOCK; - goto error; - } - goto stop; - } else { - /* - * (Semi-)Eof in parent. - * - * Now this is a bit different. The partial data waiting is - * converted and returned. - */ - - if (ResultGenerate(cd, 0, Z_SYNC_FLUSH, errorCodePtr) < 0) { - goto error; + return -1; } + return gotBytes; + } - if (Tcl_DStringLength(&cd->result) == 0) { - /* - * The drain delivered nothing. - */ + /* + * (Semi-)Eof in parent. + * + * Now this is a bit different. The partial data waiting is + * converted and returned. + */ - goto stop; - } + if (ResultGenerate(cd, 0, Z_SYNC_FLUSH, errorCodePtr) != TCL_OK) { + return -1; + } + if (Tcl_DStringLength(&cd->decompressed) == 0) { /* - * Reset eof, force caller to drain result buffer. + * The drain delivered nothing. Time to deliver what we've + * got. */ - ((Channel *) cd->parent)->state->flags &= ~CHANNEL_EOF; - continue; /* at: while (toRead > 0) */ + return gotBytes; } - } /* readBytes == 0 */ - /* - * Transform the read chunk, which was not empty. Anything we get back - * is a transformation result to be put into our buffers, and the next - * iteration will put it into the result. - */ + /* + * Reset eof, force caller to drain result buffer. + */ - if (ResultGenerate(cd, readBytes, Z_NO_FLUSH, errorCodePtr) < 0) { - goto error; - } - } /* while toRead > 0 */ + ((Channel *) cd->parent)->state->flags &= ~CHANNEL_EOF; + } else /* readBytes > 0 */ { + /* + * Transform the read chunk, which was not empty. Anything we get + * back is a transformation result to be put into our buffers, and + * the next iteration will put it into the result. + */ - stop: + if (ResultGenerate(cd, readBytes, Z_NO_FLUSH, + errorCodePtr) != TCL_OK) { + return -1; + } + } + } return gotBytes; - - error: - gotBytes = -1; - goto stop; } + +/* + *---------------------------------------------------------------------- + * + * ZlibTransformOutput -- + * + * Writer filter that does compression. + * + *---------------------------------------------------------------------- + */ static int ZlibTransformOutput( @@ -2518,6 +2546,16 @@ ZlibTransformOutput( return toWrite - cd->outStream.avail_in; } + +/* + *---------------------------------------------------------------------- + * + * ZlibTransformSetOption -- + * + * Writing side of [fconfigure] on our channel. + * + *---------------------------------------------------------------------- + */ static int ZlibTransformSetOption( /* not used */ @@ -2568,7 +2606,7 @@ ZlibTransformSetOption( /* not used */ } if (Tcl_WriteRaw(cd->parent, cd->outBuffer, - cd->outStream.next_out - (Bytef*)cd->outBuffer) < 0) { + cd->outStream.next_out - (Bytef *) cd->outBuffer) < 0) { Tcl_AppendResult(interp, "problem flushing channel: ", Tcl_PosixError(interp), NULL); return TCL_ERROR; @@ -2589,6 +2627,16 @@ ZlibTransformSetOption( /* not used */ return setOptionProc(Tcl_GetChannelInstanceData(cd->parent), interp, optionName, value); } + +/* + *---------------------------------------------------------------------- + * + * ZlibTransformGetOption -- + * + * Reading side of [fconfigure] on our channel. + * + *---------------------------------------------------------------------- + */ static int ZlibTransformGetOption( @@ -2665,6 +2713,17 @@ ZlibTransformGetOption( } return Tcl_BadChannelOption(interp, optionName, chanOptions); } + +/* + *---------------------------------------------------------------------- + * + * ZlibTransformWatch, ZlibTransformEventHandler -- + * + * If we have data pending, trigger a readable event after a short time + * (in order to allow a real event to catch up). + * + *---------------------------------------------------------------------- + */ static void ZlibTransformWatch( @@ -2681,63 +2740,27 @@ ZlibTransformWatch( watchProc = Tcl_ChannelWatchProc(Tcl_GetChannelType(cd->parent)); watchProc(Tcl_GetChannelInstanceData(cd->parent), mask); - if (!(mask & TCL_READABLE) || - (Tcl_DStringLength(&cd->result) == 0)) { - ZlibTransformTimerKill(cd); - } else { - ZlibTransformTimerSetup(cd); - } -} - -static int -ZlibTransformGetHandle( - ClientData instanceData, - int direction, - ClientData *handlePtr) -{ - ZlibChannelData *cd = instanceData; - - return Tcl_GetChannelHandle(cd->parent, direction, handlePtr); -} - -static int -ZlibTransformBlockMode( - ClientData instanceData, - int mode) -{ - ZlibChannelData *cd = instanceData; - - if (mode == TCL_MODE_NONBLOCKING) { - cd->flags |= ASYNC; - } else { - cd->flags &= ~ASYNC; + if (!(mask & TCL_READABLE) || Tcl_DStringLength(&cd->decompressed) == 0) { + ZlibTransformEventTimerKill(cd); + } else if (cd->timer == NULL) { + cd->timer = Tcl_CreateTimerHandler(TRANSFORM_TIMEOUT, + ZlibTransformTimerRun, cd); } - return TCL_OK; } static int -ZlibTransformHandler( +ZlibTransformEventHandler( ClientData instanceData, int interestMask) { ZlibChannelData *cd = instanceData; - ZlibTransformTimerKill(cd); + ZlibTransformEventTimerKill(cd); return interestMask; } -static void -ZlibTransformTimerSetup( - ZlibChannelData *cd) -{ - if (cd->timer == NULL) { - cd->timer = Tcl_CreateTimerHandler(0, - ZlibTransformTimerRun, cd); - } -} - -static void -ZlibTransformTimerKill( +static inline void +ZlibTransformEventTimerKill( ZlibChannelData *cd) { if (cd->timer != NULL) { @@ -2759,6 +2782,53 @@ ZlibTransformTimerRun( /* *---------------------------------------------------------------------- * + * ZlibTransformGetHandle -- + * + * Anything that needs the OS handle is told to get it from what we are + * stacked on top of. + * + *---------------------------------------------------------------------- + */ + +static int +ZlibTransformGetHandle( + ClientData instanceData, + int direction, + ClientData *handlePtr) +{ + ZlibChannelData *cd = instanceData; + + return Tcl_GetChannelHandle(cd->parent, direction, handlePtr); +} + +/* + *---------------------------------------------------------------------- + * + * ZlibTransformBlockMode -- + * + * We need to keep track of the blocking mode; it changes our behavior. + * + *---------------------------------------------------------------------- + */ + +static int +ZlibTransformBlockMode( + ClientData instanceData, + int mode) +{ + ZlibChannelData *cd = instanceData; + + if (mode == TCL_MODE_NONBLOCKING) { + cd->flags |= ASYNC; + } else { + cd->flags &= ~ASYNC; + } + return TCL_OK; +} + +/* + *---------------------------------------------------------------------- + * * ZlibStackChannelTransform -- * * Stacks either compression or decompression onto a channel. @@ -2870,7 +2940,7 @@ ZlibStackChannelTransform( } } - Tcl_DStringInit(&cd->result); + Tcl_DStringInit(&cd->decompressed); chan = Tcl_StackChannel(interp, &zlibChannelType, cd, Tcl_GetChannelMode(channel), channel); @@ -2913,13 +2983,13 @@ ZlibStackChannelTransform( *---------------------------------------------------------------------- */ -static int +static inline int ResultCopy( - Tcl_DString *ds, /* The buffer to read from */ - unsigned char *buf, /* The buffer to copy into */ + ZlibChannelData *cd, /* The location of the buffer to read from. */ + char *buf, /* The buffer to copy into */ int toRead) /* Number of requested bytes */ { - int have = Tcl_DStringLength(ds); + int have = Tcl_DStringLength(&cd->decompressed); if (have == 0) { /* @@ -2927,20 +2997,19 @@ ResultCopy( */ return 0; - } - if (have > toRead) { + } else if (have > toRead) { /* * The internal buffer contains more than requested. Copy the * requested subset to the caller, shift the remaining bytes down, and * truncate. */ - char *src = Tcl_DStringValue(ds); + char *src = Tcl_DStringValue(&cd->decompressed); memcpy(buf, src, toRead); memmove(src, src + toRead, have - toRead); - Tcl_DStringSetLength(ds, have - toRead); + Tcl_DStringSetLength(&cd->decompressed, have - toRead); return toRead; } else /* have <= toRead */ { /* @@ -2948,8 +3017,8 @@ ResultCopy( * caller, so take everything as best effort. */ - memcpy(buf, Tcl_DStringValue(ds), have); - Tcl_DStringSetLength(ds, 0); + memcpy(buf, Tcl_DStringValue(&cd->decompressed), have); + Tcl_DStringSetLength(&cd->decompressed, 0); return have; } } @@ -2963,7 +3032,7 @@ ResultCopy( * in our working buffer. * * Result: - * Zero on success, -1 on error (with *errorCodePtr updated with reason). + * TCL_OK/TCL_ERROR (with *errorCodePtr updated with reason). * * Side effects: * See above. @@ -2998,7 +3067,7 @@ ResultGenerate( written = MAXBUF - cd->inStream.avail_out; if (written) { - Tcl_DStringAppend(&cd->result, (char*) buf, written); + Tcl_DStringAppend(&cd->decompressed, (char *) buf, written); } /* @@ -3008,7 +3077,7 @@ ResultGenerate( if (((flush == Z_SYNC_FLUSH) && (e == Z_BUF_ERROR)) || (e == Z_STREAM_END) || (e == Z_OK && cd->inStream.avail_out == 0)) { - return 0; + return TCL_OK; } /* @@ -3027,7 +3096,7 @@ ResultGenerate( Tcl_NewStringObj(cd->inStream.msg, -1)); Tcl_SetChannelError(cd->parent, errObj); *errorCodePtr = EINVAL; - return -1; + return TCL_ERROR; } /* @@ -3035,7 +3104,7 @@ ResultGenerate( */ if (cd->inStream.avail_in <= 0 && flush != Z_SYNC_FLUSH) { - return 0; + return TCL_OK; } } } -- cgit v0.12