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author | dgp <dgp@users.sourceforge.net> | 2014-03-20 16:31:11 (GMT) |
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committer | dgp <dgp@users.sourceforge.net> | 2014-03-20 16:31:11 (GMT) |
commit | eae6f97866efd02f09d961bf695047a3b47ac961 (patch) | |
tree | 2accfbab182c0860924e2bbd672f8ebacca0ac25 /generic/tclIO.c | |
parent | 4033e67b9e4a36d0f19804bfca308d32c12d4af2 (diff) | |
download | tcl-eae6f97866efd02f09d961bf695047a3b47ac961.zip tcl-eae6f97866efd02f09d961bf695047a3b47ac961.tar.gz tcl-eae6f97866efd02f09d961bf695047a3b47ac961.tar.bz2 |
Use assertions about the pushback buffers to simplify their handling.
Mark several things left TODO. Some tidying.
Diffstat (limited to 'generic/tclIO.c')
-rw-r--r-- | generic/tclIO.c | 60 |
1 files changed, 37 insertions, 23 deletions
diff --git a/generic/tclIO.c b/generic/tclIO.c index 267b659..b423bcc 100644 --- a/generic/tclIO.c +++ b/generic/tclIO.c @@ -6,6 +6,7 @@ * * Copyright (c) 1998-2000 Ajuba Solutions * Copyright (c) 1995-1997 Sun Microsystems, Inc. + * Contributions from Don Porter, NIST, 2014. (not subject to US copyright) * * See the file "license.terms" for information on usage and redistribution of * this file, and for a DISCLAIMER OF ALL WARRANTIES. @@ -1679,17 +1680,17 @@ Tcl_StackChannel( */ if (((mask & TCL_READABLE) != 0) && (statePtr->inQueueHead != NULL)) { + /* - * Remark: It is possible that the channel buffers contain data from - * some earlier push-backs. + * When statePtr->inQueueHead is not NULL, we know + * prevChanPtr->inQueueHead must be NULL. */ - statePtr->inQueueTail->nextPtr = prevChanPtr->inQueueHead; - prevChanPtr->inQueueHead = statePtr->inQueueHead; + assert(prevChanPtr->inQueueHead == NULL); + assert(prevChanPtr->inQueueTail == NULL); - if (prevChanPtr->inQueueTail == NULL) { - prevChanPtr->inQueueTail = statePtr->inQueueTail; - } + prevChanPtr->inQueueHead = statePtr->inQueueHead; + prevChanPtr->inQueueTail = statePtr->inQueueTail; statePtr->inQueueHead = NULL; statePtr->inQueueTail = NULL; @@ -2254,6 +2255,7 @@ RecycleBuffer( } /* + * TODO * Only save buffers which are at least as big as the requested buffersize * for the channel. This is to honor dynamic changes of the buffersize * made by the user. @@ -3696,9 +3698,7 @@ Write( &statePtr->outputEncodingState, dst, dstLen + BUFFER_PADDING, &srcRead, &dstWrote, NULL); - if (srcRead != nlLen) { - Tcl_Panic("Can This Happen?"); - } + assert (srcRead == nlLen); bufPtr->nextAdded += dstWrote; src++; @@ -4837,6 +4837,7 @@ Tcl_ReadRaw( int nread, result, copied, copiedNow; /* + * TODO VERIFY * The check below does too much because it will reject a call to this * function with a channel which is part of an 'fcopy'. But we have to * allow this here or else the chaining in the transformation drivers will @@ -5925,16 +5926,11 @@ GetInput( * channel in the stack and use them. They can be the result of a * transformation which went away without reading all the information * placed in the area when it was stacked. - * - * Two possibilities for the state: No buffers in it, or a single empty - * buffer. In the latter case we can recycle it now. */ if (chanPtr->inQueueHead != NULL) { - if (statePtr->inQueueHead != NULL) { - RecycleBuffer(statePtr, statePtr->inQueueHead, 0); - statePtr->inQueueHead = NULL; - } + + assert(statePtr->inQueueHead == NULL); statePtr->inQueueHead = chanPtr->inQueueHead; statePtr->inQueueTail = chanPtr->inQueueTail; @@ -5962,6 +5958,7 @@ GetInput( statePtr->saveInBufPtr = NULL; /* + * TODO * Check the actual buffersize against the requested buffersize. * Buffers which are smaller than requested are squashed. This is done * to honor dynamic changes of the buffersize made by the user. @@ -5979,6 +5976,7 @@ GetInput( bufPtr->nextPtr = NULL; /* + * TODO * SF #427196: Use the actual size of the buffer to determine the * number of bytes to read from the channel and not the size for new * buffers. They can be different if the buffersize was changed @@ -6003,6 +6001,7 @@ GetInput( } /* + * TODO * If EOF is set, we should avoid calling the driver because on some * platforms it is impossible to read from a device after EOF. */ @@ -6524,6 +6523,7 @@ CheckChannelErrors( if (direction == TCL_READABLE) { /* + * TODO * If we have not encountered a sticky EOF, clear the EOF bit (sticky * EOF is set if we have seen the input eofChar, to prevent reading * beyond the eofChar). Also, always clear the BLOCKED bit. We want to @@ -6739,6 +6739,7 @@ Tcl_SetChannelBufferSize( ChannelState *statePtr; /* State of real channel structure. */ /* + * TODO * Clip the buffer size to force it into the [1,1M] range */ @@ -7375,6 +7376,7 @@ Tcl_SetChannelOption( } /* + * TODO * If bufsize changes, need to get rid of old utility buffer. */ @@ -8677,18 +8679,23 @@ DoRead( /* * Each pass through the loop is intended to process up to * one channel buffer. - * - * First, if there is no full buffer, we attempt to - * create and/or fill one. */ + int bytesRead, bytesWritten; 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; } + /* If there is no full buffer, attempt to create and/or fill one. */ + while (bufPtr == NULL || !IsBufferFull(bufPtr)) { int code; @@ -8696,6 +8703,9 @@ DoRead( moreData: code = GetInput(chanPtr); bufPtr = statePtr->inQueueHead; + + assert (bufPtr != NULL); + if (statePtr->flags & (CHANNEL_EOF|CHANNEL_BLOCKED)) { /* Further reads cannot do any more */ break; @@ -8706,11 +8716,14 @@ DoRead( UpdateInterest(chanPtr); return -1; } + + assert (IsBufferFull(bufPtr)); } - /* Here we know bufPtr != NULL */ - int bytesRead = BytesLeft(bufPtr); - int bytesWritten = bytesToRead; + assert (bufPtr != NULL); + + bytesRead = BytesLeft(bufPtr); + bytesWritten = bytesToRead; TranslateInputEOL(statePtr, p, RemovePoint(bufPtr), &bytesWritten, &bytesRead); @@ -10155,6 +10168,7 @@ SetChannelFromAny( } if (objPtr->typePtr == &chanObjType) { /* + * TODO: TAINT Flag and dup'd channel values? * The channel is valid until any call to DetachChannel occurs. * Ensure consistency checks are done. */ |