/* * 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 1.1.1.1 2007/07/10 15:04:23 duncan 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, CONST 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, CONST char *optionName, CONST char *value)); static int TransformGetOptionProc _ANSI_ARGS_(( ClientData instanceData, Tcl_Interp *interp, CONST 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)); static Tcl_WideInt TransformWideSeekProc _ANSI_ARGS_ (( ClientData instanceData, Tcl_WideInt offset, int mode, int* errorCodePtr)); /* * 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_3, 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 */ TransformWideSeekProc, /* Wide seek proc */ }; /* * 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 FLUSH_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_EvalObjEx(dataPtr->interp, command, TCL_EVAL_GLOBAL); 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; CONST 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. */ { 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. */ return (*parentSeekProc) (Tcl_GetChannelInstanceData(parent), offset, mode, errorCodePtr); } /* * 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; } return (*parentSeekProc) (Tcl_GetChannelInstanceData(parent), offset, mode, errorCodePtr); } /* *---------------------------------------------------------------------- * * TransformWideSeekProc -- * * This procedure is called by the generic IO level to move the * access point in a channel, with a (potentially) 64-bit offset. * * Side effects: * 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 Tcl_WideInt TransformWideSeekProc (instanceData, offset, mode, errorCodePtr) ClientData instanceData; /* The channel to manipulate */ Tcl_WideInt offset; /* Size of movement. */ int mode; /* How to move */ int* errorCodePtr; /* Location of error flag. */ { TransformChannelData* dataPtr = (TransformChannelData*) instanceData; Tcl_Channel parent = Tcl_GetStackedChannel(dataPtr->self); Tcl_ChannelType* parentType = Tcl_GetChannelType(parent); Tcl_DriverSeekProc* parentSeekProc = Tcl_ChannelSeekProc(parentType); Tcl_DriverWideSeekProc* parentWideSeekProc = Tcl_ChannelWideSeekProc(parentType); ClientData parentData = Tcl_GetChannelInstanceData(parent); if ((offset == Tcl_LongAsWide(0)) && (mode == SEEK_CUR)) { /* * This is no seek but a request to tell the caller the current * location. Simply pass the request down. */ if (parentWideSeekProc != NULL) { return (*parentWideSeekProc) (parentData, offset, mode, errorCodePtr); } return Tcl_LongAsWide((*parentSeekProc) (parentData, 0, mode, errorCodePtr)); } /* * 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; } /* * If we have a wide seek capability, we should stick with that. */ if (parentWideSeekProc != NULL) { return (*parentWideSeekProc) (parentData, offset, mode, errorCodePtr); } /* * We're transferring to narrow seeks at this point; this is a bit * complex because we have to check whether the seek is possible * first (i.e. whether we are losing information in truncating the * bits of the offset.) Luckily, there's a defined error for what * happens when trying to go out of the representable range. */ if (offsetTcl_LongAsWide(LONG_MAX)) { *errorCodePtr = EOVERFLOW; return Tcl_LongAsWide(-1); } return Tcl_LongAsWide((*parentSeekProc) (parentData, Tcl_WideAsLong(offset), mode, errorCodePtr)); } /* *------------------------------------------------------* * * 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; CONST char *optionName; CONST 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; CONST 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 == (CONST 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 (FLUSH_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; }