diff options
Diffstat (limited to 'generic/tclIO.c')
| -rw-r--r-- | generic/tclIO.c | 226 |
1 files changed, 184 insertions, 42 deletions
diff --git a/generic/tclIO.c b/generic/tclIO.c index 9cbc72c..8ec2a1e 100644 --- a/generic/tclIO.c +++ b/generic/tclIO.c @@ -4394,6 +4394,21 @@ Tcl_GetsObj( } /* + * If we're sitting ready to read the eofchar, there's no need to + * do it. + */ + + if (GotFlag(statePtr, CHANNEL_STICKY_EOF)) { + SetFlag(statePtr, CHANNEL_EOF); + assert( statePtr->inputEncodingFlags & TCL_ENCODING_END ); + assert( !GotFlag(statePtr, CHANNEL_BLOCKED|INPUT_SAW_CR) ); + + /* TODO: Do we need this? */ + UpdateInterest(chanPtr); + return -1; + } + + /* * A binary version of Tcl_GetsObj. This could also handle encodings that * are ascii-7 pure (iso8859, utf-8, ...) with a final encoding conversion * done on objPtr. @@ -4611,6 +4626,7 @@ Tcl_GetsObj( dstEnd = eof; SetFlag(statePtr, CHANNEL_EOF | CHANNEL_STICKY_EOF); statePtr->inputEncodingFlags |= TCL_ENCODING_END; + ResetFlag(statePtr, CHANNEL_BLOCKED|INPUT_SAW_CR); } if (GotFlag(statePtr, CHANNEL_EOF)) { skip = 0; @@ -4724,6 +4740,13 @@ Tcl_GetsObj( */ done: + assert(!GotFlag(statePtr, CHANNEL_EOF) + || GotFlag(statePtr, CHANNEL_STICKY_EOF) + || Tcl_InputBuffered((Tcl_Channel)chanPtr) == 0); + + assert( !(GotFlag(statePtr, CHANNEL_EOF|CHANNEL_BLOCKED) + == (CHANNEL_EOF|CHANNEL_BLOCKED)) ); + /* * Regenerate the top channel, in case it was changed due to * self-modifying reflected transforms. @@ -4747,6 +4770,11 @@ Tcl_GetsObj( * end-of-line or end-of-file has been seen. Bytes read from the input * channel return as a ByteArray obj. * + * WARNING! The notion of "binary" used here is different from + * notions of "binary" used in other places. In particular, this + * "binary" routine may be called when an -eofchar is set on the + * channel. + * * Results: * Number of characters accumulated in the object or -1 if error, * blocked, or EOF. If -1, use Tcl_GetErrno() to retrieve the POSIX error @@ -4835,6 +4863,17 @@ TclGetsObjBinary( if (bufPtr == NULL) { goto restore; } + } else { + /* + * Incoming CHANNEL_STICKY_EOF is filtered out on entry. + * A new CHANNEL_STICKY_EOF set in this routine leads to + * return before coming back here. When we are not dealing + * with CHANNEL_STICKY_EOF, a CHANNEL_EOF implies an + * empty buffer. Here the buffer is non-empty so we know + * we're a non-EOF */ + + assert ( !GotFlag(statePtr, CHANNEL_STICKY_EOF) ); + assert ( !GotFlag(statePtr, CHANNEL_EOF) ); } dst = (unsigned char *) RemovePoint(bufPtr); @@ -4876,6 +4915,7 @@ TclGetsObjBinary( SetFlag(statePtr, CHANNEL_EOF | CHANNEL_STICKY_EOF); statePtr->inputEncodingFlags |= TCL_ENCODING_END; + ResetFlag(statePtr, CHANNEL_BLOCKED|INPUT_SAW_CR); } if (GotFlag(statePtr, CHANNEL_EOF)) { skip = 0; @@ -4985,6 +5025,11 @@ TclGetsObjBinary( */ done: + assert(!GotFlag(statePtr, CHANNEL_EOF) + || GotFlag(statePtr, CHANNEL_STICKY_EOF) + || Tcl_InputBuffered((Tcl_Channel)chanPtr) == 0); + assert( !(GotFlag(statePtr, CHANNEL_EOF|CHANNEL_BLOCKED) + == (CHANNEL_EOF|CHANNEL_BLOCKED)) ); UpdateInterest(chanPtr); TclChannelRelease((Tcl_Channel)chanPtr); return copiedTotal; @@ -5115,6 +5160,17 @@ FilterInputBytes( gsPtr->rawRead = 0; return -1; } + } else { + /* + * Incoming CHANNEL_STICKY_EOF is filtered out on entry. + * A new CHANNEL_STICKY_EOF set in this routine leads to + * return before coming back here. When we are not dealing + * with CHANNEL_STICKY_EOF, a CHANNEL_EOF implies an + * empty buffer. Here the buffer is non-empty so we know + * we're a non-EOF */ + + assert ( !GotFlag(statePtr, CHANNEL_STICKY_EOF) ); + assert ( !GotFlag(statePtr, CHANNEL_EOF) ); } /* @@ -5439,6 +5495,7 @@ Tcl_ReadRaw( /* State info for channel */ int copied = 0; + assert(bytesToRead > 0); if (CheckChannelErrors(statePtr, TCL_READABLE | CHANNEL_RAW_MODE) != 0) { return -1; } @@ -5470,8 +5527,19 @@ Tcl_ReadRaw( } } - /* Go to the driver if more data needed. */ + /* + * Go to the driver only if we got nothing from pushback. + * Have to do it this way to avoid EOF mis-timings when we + * consider the ability that EOF may not be a permanent + * condition in the driver, and in that case we have to + * synchronize. + */ + + if (copied) { + return copied; + } + /* This test not needed. */ if (bytesToRead > 0) { int nread = ChanRead(chanPtr, readBuf, bytesToRead); @@ -5494,12 +5562,10 @@ Tcl_ReadRaw( if (!GotFlag(statePtr, CHANNEL_BLOCKED) || copied == 0) { copied = -1; } - } else if (copied > 0) { + } else { /* - * nread == 0. Driver is at EOF, but if copied>0 bytes - * from pushback, then we should not signal it yet. + * nread == 0. Driver is at EOF. Let that state filter up. */ - ResetFlag(statePtr, CHANNEL_EOF); } } return copied; @@ -5598,19 +5664,11 @@ DoReadChars( ChannelState *statePtr = chanPtr->state; /* State info for channel */ ChannelBuffer *bufPtr; - int factor, copied, copiedNow, result; - Tcl_Encoding encoding; + int copied, copiedNow, result; + Tcl_Encoding encoding = statePtr->encoding; int binaryMode; #define UTF_EXPANSION_FACTOR 1024 - - /* - * This operation should occur at the top of a channel stack. - */ - - chanPtr = statePtr->topChanPtr; - encoding = statePtr->encoding; - factor = UTF_EXPANSION_FACTOR; - TclChannelPreserve((Tcl_Channel)chanPtr); + int factor = UTF_EXPANSION_FACTOR; binaryMode = (encoding == NULL) && (statePtr->inputTranslation == TCL_TRANSLATE_LF) @@ -5634,6 +5692,36 @@ DoReadChars( } } + /* + * Early out when next read will see eofchar. + * + * NOTE: See DoRead for argument that it's a bug (one we're keeping) + * to have this escape before the one for zero-char read request. + */ + + if (GotFlag(statePtr, CHANNEL_STICKY_EOF)) { + SetFlag(statePtr, CHANNEL_EOF); + assert( statePtr->inputEncodingFlags & TCL_ENCODING_END ); + assert( !GotFlag(statePtr, CHANNEL_BLOCKED|INPUT_SAW_CR) ); + + UpdateInterest(chanPtr); + return 0; + } + + /* Special handling for zero-char read request. */ + if (toRead == 0) { + ResetFlag(statePtr, CHANNEL_BLOCKED|CHANNEL_EOF); + UpdateInterest(chanPtr); + return 0; + } + + /* + * This operation should occur at the top of a channel stack. + */ + + chanPtr = statePtr->topChanPtr; + TclChannelPreserve((Tcl_Channel)chanPtr); + /* Must clear the BLOCKED flag here since we check before reading */ ResetFlag(statePtr, CHANNEL_BLOCKED); for (copied = 0; (unsigned) toRead > 0; ) { @@ -5710,6 +5798,11 @@ DoReadChars( * Update the notifier state so we don't block while there is still data * in the buffers. */ + assert(!GotFlag(statePtr, CHANNEL_EOF) + || GotFlag(statePtr, CHANNEL_STICKY_EOF) + || Tcl_InputBuffered((Tcl_Channel)chanPtr) == 0); + assert( !(GotFlag(statePtr, CHANNEL_EOF|CHANNEL_BLOCKED) + == (CHANNEL_EOF|CHANNEL_BLOCKED)) ); UpdateInterest(chanPtr); TclChannelRelease((Tcl_Channel)chanPtr); return copied; @@ -6318,7 +6411,7 @@ TranslateInputEOL( SetFlag(statePtr, CHANNEL_EOF | CHANNEL_STICKY_EOF); statePtr->inputEncodingFlags |= TCL_ENCODING_END; - ResetFlag(statePtr, INPUT_SAW_CR); + ResetFlag(statePtr, CHANNEL_BLOCKED|INPUT_SAW_CR); } } @@ -6528,6 +6621,14 @@ GetInput( ChannelState *statePtr = chanPtr->state; /* State info for channel */ + /* + * Verify that all callers know better than to call us when + * it's recorded that the next char waiting to be read is the + * eofchar. + */ + + assert( !GotFlag(statePtr, CHANNEL_STICKY_EOF) ); + /* * Prevent reading from a dead channel -- a channel that has been closed * but not yet deallocated, which can happen if the exit handler for @@ -6539,18 +6640,24 @@ GetInput( return EINVAL; } - /* - * For a channel at EOF do not bother allocating buffers; there's - * nothing more to read. Avoid calling the driver inputproc in - * case some of them do not react well to additional calls after - * they've reported an eof state.. - * TODO: Candidate for a can't happen panic. + /* + * WARNING: There was once a comment here claiming that it was + * a bad idea to make another call to the inputproc of a channel + * driver when EOF has already been detected on the channel. Through + * much of Tcl's history, this warning was then completely negated + * by having all (most?) read paths clear the EOF setting before + * reaching here. So we had a guard that was never triggered. + * + * Don't be tempted to restore the guard. Even if EOF is set on + * the channel, continue through and call the inputproc again. This + * is the way to enable the ability to [read] again beyond the EOF, + * which seems a strange thing to do, but for which use cases exist + * [Tcl Bug 5adc350683] and which may even be essential for channels + * representing things like ttys or other devices where the stream + * might take the logical form of a series of 'files' separated by + * an EOF condition. */ - if (GotFlag(statePtr, CHANNEL_EOF)) { - return 0; - } - /* * First check for more buffers in the pushback area of the topmost * channel in the stack and use them. They can be the result of a @@ -6560,6 +6667,7 @@ GetInput( if (chanPtr->inQueueHead != NULL) { + /* TODO: Tests to cover this. */ assert(statePtr->inQueueHead == NULL); statePtr->inQueueHead = chanPtr->inQueueHead; @@ -6590,6 +6698,7 @@ GetInput( * Check the actual buffersize against the requested buffersize. * Saved buffers of the wrong size are squashed. This is done * to honor dynamic changes of the buffersize made by the user. + * TODO: Tests to cover this. */ if ((bufPtr != NULL) @@ -7107,9 +7216,7 @@ Tcl_Eof( ChannelState *statePtr = ((Channel *) chan)->state; /* State of real channel structure. */ - return (GotFlag(statePtr, CHANNEL_STICKY_EOF) || - (GotFlag(statePtr, CHANNEL_EOF) && - (Tcl_InputBuffered(chan) == 0))) ? 1 : 0; + return GotFlag(statePtr, CHANNEL_EOF) ? 1 : 0; } /* @@ -9496,6 +9603,36 @@ DoRead( ChannelState *statePtr = chanPtr->state; char *p = dst; + assert (bytesToRead >= 0); + + /* + * Early out when we know a read will get the eofchar. + * + * NOTE: This seems to be a bug. The special handling for + * a zero-char read request ought to come first. As coded + * the EOF due to eofchar has distinguishing behavior from + * the EOF due to reported EOF on the underlying device, and + * that seems undesirable. However recent history indicates + * that new inconsistent behavior in a patchlevel has problems + * too. Keep on keeping on for now. + */ + + if (GotFlag(statePtr, CHANNEL_STICKY_EOF)) { + SetFlag(statePtr, CHANNEL_EOF); + assert( statePtr->inputEncodingFlags & TCL_ENCODING_END ); + assert( !GotFlag(statePtr, CHANNEL_BLOCKED|INPUT_SAW_CR) ); + + UpdateInterest(chanPtr); + return 0; + } + + /* Special handling for zero-char read request. */ + if (bytesToRead == 0) { + ResetFlag(statePtr, CHANNEL_BLOCKED|CHANNEL_EOF); + UpdateInterest(chanPtr); + return 0; + } + TclChannelPreserve((Tcl_Channel)chanPtr); while (bytesToRead) { /* @@ -9507,16 +9644,6 @@ DoRead( ChannelBuffer *bufPtr = statePtr->inQueueHead; /* - * When there's no buffered data to read, and we're at EOF, - * escape to the caller. - */ - - if (statePtr->flags & CHANNEL_EOF - && (bufPtr == NULL || IsBufferEmpty(bufPtr))) { - break; - } - - /* * Don't read more data if we have what we need. */ @@ -9576,8 +9703,7 @@ DoRead( * 1) We're @EOF because we saw eof char. */ - if (statePtr->inEofChar - && RemovePoint(bufPtr)[0] == statePtr->inEofChar) { + if (GotFlag(statePtr, CHANNEL_STICKY_EOF)) { UpdateInterest(chanPtr); break; } @@ -9628,17 +9754,33 @@ DoRead( statePtr->inQueueTail = NULL; } RecycleBuffer(statePtr, bufPtr, 0); + bufPtr = statePtr->inQueueHead; } if ((GotFlag(statePtr, CHANNEL_NONBLOCKING) || allowShortReads) && GotFlag(statePtr, CHANNEL_BLOCKED)) { break; } + + /* + * When there's no buffered data to read, and we're at EOF, + * escape to the caller. + */ + + if (GotFlag(statePtr, CHANNEL_EOF) + && (bufPtr == NULL || IsBufferEmpty(bufPtr))) { + break; + } } if (bytesToRead == 0) { ResetFlag(statePtr, CHANNEL_BLOCKED); } + assert(!GotFlag(statePtr, CHANNEL_EOF) + || GotFlag(statePtr, CHANNEL_STICKY_EOF) + || Tcl_InputBuffered((Tcl_Channel)chanPtr) == 0); + assert( !(GotFlag(statePtr, CHANNEL_EOF|CHANNEL_BLOCKED) + == (CHANNEL_EOF|CHANNEL_BLOCKED)) ); TclChannelRelease((Tcl_Channel)chanPtr); return (int)(p - dst); } |