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authordgp <dgp@users.sourceforge.net>2014-11-03 21:04:24 (GMT)
committerdgp <dgp@users.sourceforge.net>2014-11-03 21:04:24 (GMT)
commit7903c310683834f01564dde909b82e008ea07947 (patch)
tree8c3332dff5bedbcd40d1ab43f2676574601e0a52 /generic/tclIO.c
parent5b84b16e1fee2a7da08f3e3a3f0bb7a0ea5a72a8 (diff)
parent5a0bdb1baf6c35b490aa2d34d5ea5aec3ae66831 (diff)
downloadtcl-7903c310683834f01564dde909b82e008ea07947.zip
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Same patch re-enabling read after EOF, but here applied to 8.6.
Likely additional changes needed in the other channel transforms new in 8.6.
Diffstat (limited to 'generic/tclIO.c')
-rw-r--r--generic/tclIO.c226
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);
}