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-rw-r--r--generic/tclIO.c95
1 files changed, 89 insertions, 6 deletions
diff --git a/generic/tclIO.c b/generic/tclIO.c
index 93bd0de..1a40828 100644
--- a/generic/tclIO.c
+++ b/generic/tclIO.c
@@ -10,7 +10,7 @@
* See the file "license.terms" for information on usage and redistribution
* of this file, and for a DISCLAIMER OF ALL WARRANTIES.
*
- * RCS: @(#) $Id: tclIO.c,v 1.73 2004/04/23 23:38:42 andreas_kupries Exp $
+ * RCS: @(#) $Id: tclIO.c,v 1.74 2004/05/19 19:41:09 andreas_kupries Exp $
*/
#include "tclInt.h"
@@ -4237,8 +4237,18 @@ Tcl_ReadRaw(chan, bufPtr, bytesToRead)
statePtr->flags &= (~(CHANNEL_BLOCKED));
}
- if ((statePtr->flags & CHANNEL_TIMER_FEV) &&
- (statePtr->flags & CHANNEL_NONBLOCKING)) {
+ /* [SF Tcl Bug 943274]. Better emulation of non-blocking
+ * channels for channels without BlockModeProc, by keeping
+ * track of true fileevents generated by the OS == Data
+ * waiting and reading if and only if we are sure to have
+ * data.
+ */
+
+ if ((statePtr->flags & CHANNEL_NONBLOCKING) &&
+ (Tcl_ChannelBlockModeProc(chanPtr->typePtr) == NULL) &&
+ !(statePtr->flags & CHANNEL_HAS_MORE_DATA)) {
+
+ /* We bypass the driver, it would block, as no data is available */
nread = -1;
result = EWOULDBLOCK;
} else {
@@ -4266,6 +4276,12 @@ Tcl_ReadRaw(chan, bufPtr, bytesToRead)
if (nread < (bytesToRead - copied)) {
statePtr->flags |= CHANNEL_BLOCKED;
}
+
+ if (nread <= (bytesToRead - copied)) {
+ /* [SF Tcl Bug 943274] We have read the available
+ * data, clear flag */
+ statePtr->flags &= ~CHANNEL_HAS_MORE_DATA;
+ }
} else if (nread == 0) {
statePtr->flags |= CHANNEL_EOF;
statePtr->inputEncodingFlags |= TCL_ENCODING_END;
@@ -4390,7 +4406,7 @@ DoReadChars(chanPtr, objPtr, toRead, appendFlag)
int offset, factor, copied, copiedNow, result;
Tcl_Encoding encoding;
#define UTF_EXPANSION_FACTOR 1024
-
+
/*
* This operation should occur at the top of a channel stack.
*/
@@ -5307,8 +5323,17 @@ GetInput(chanPtr)
return 0;
}
- if ((statePtr->flags & CHANNEL_TIMER_FEV) &&
- (statePtr->flags & CHANNEL_NONBLOCKING)) {
+ /* [SF Tcl Bug 943274]. Better emulation of non-blocking channels
+ * for channels without BlockModeProc, by keeping track of true
+ * fileevents generated by the OS == Data waiting and reading if
+ * and only if we are sure to have data.
+ */
+
+ if ((statePtr->flags & CHANNEL_NONBLOCKING) &&
+ (Tcl_ChannelBlockModeProc(chanPtr->typePtr) == NULL) &&
+ !(statePtr->flags & CHANNEL_HAS_MORE_DATA)) {
+
+ /* Bypass the driver, it would block, as no data is available */
nread = -1;
result = EWOULDBLOCK;
} else {
@@ -5329,6 +5354,13 @@ GetInput(chanPtr)
if (nread < toRead) {
statePtr->flags |= CHANNEL_BLOCKED;
}
+
+ if (nread <= toRead) {
+ /* [SF Tcl Bug 943274] We have read the available data,
+ * clear flag */
+ statePtr->flags &= ~CHANNEL_HAS_MORE_DATA;
+ }
+
} else if (nread == 0) {
statePtr->flags |= CHANNEL_EOF;
statePtr->inputEncodingFlags |= TCL_ENCODING_END;
@@ -6729,6 +6761,20 @@ Tcl_NotifyChannel(channel, mask)
Channel* upChanPtr;
Tcl_ChannelType* upTypePtr;
+ /* [SF Tcl Bug 943274]
+ * For a non-blocking channel without blockmodeproc we keep track
+ * of actual input coming from the OS so that we can do a credible
+ * imitation of non-blocking behaviour.
+ */
+
+ if ((mask & TCL_READABLE) &&
+ (statePtr->flags & CHANNEL_NONBLOCKING) &&
+ (Tcl_ChannelBlockModeProc(chanPtr->typePtr) == NULL) &&
+ !(statePtr->flags & CHANNEL_TIMER_FEV)) {
+
+ statePtr->flags |= CHANNEL_HAS_MORE_DATA;
+ }
+
/*
* In contrast to the other API functions this procedure walks towards
* the top of a stack and not down from it.
@@ -9185,3 +9231,40 @@ Tcl_ChannelWideSeekProc(chanTypePtr)
return NULL;
}
}
+
+#if 0
+/* For future debugging work, a simple function to print the flags of
+ * a channel in semi-readable form.
+ */
+
+static int
+DumpFlags (str, flags)
+ char* str;
+ int flags;
+{
+ char buf [20];
+ int i = 0;
+
+ if (flags & TCL_READABLE) {buf[i] = 'r';} else {buf [i]='_';}; i++;
+ if (flags & TCL_WRITABLE) {buf[i] = 'w';} else {buf [i]='_';}; i++;
+ if (flags & CHANNEL_NONBLOCKING) {buf[i] = 'n';} else {buf [i]='_';}; i++;
+ if (flags & CHANNEL_LINEBUFFERED) {buf[i] = 'l';} else {buf [i]='_';}; i++;
+ if (flags & CHANNEL_UNBUFFERED) {buf[i] = 'u';} else {buf [i]='_';}; i++;
+ if (flags & BUFFER_READY) {buf[i] = 'R';} else {buf [i]='_';}; i++;
+ if (flags & BG_FLUSH_SCHEDULED) {buf[i] = 'F';} else {buf [i]='_';}; i++;
+ if (flags & CHANNEL_CLOSED) {buf[i] = 'c';} else {buf [i]='_';}; i++;
+ if (flags & CHANNEL_EOF) {buf[i] = 'E';} else {buf [i]='_';}; i++;
+ if (flags & CHANNEL_STICKY_EOF) {buf[i] = 'S';} else {buf [i]='_';}; i++;
+ if (flags & CHANNEL_BLOCKED) {buf[i] = 'B';} else {buf [i]='_';}; i++;
+ if (flags & INPUT_SAW_CR) {buf[i] = '/';} else {buf [i]='_';}; i++;
+ if (flags & INPUT_NEED_NL) {buf[i] = '*';} else {buf [i]='_';}; i++;
+ if (flags & CHANNEL_DEAD) {buf[i] = 'D';} else {buf [i]='_';}; i++;
+ if (flags & CHANNEL_RAW_MODE) {buf[i] = 'R';} else {buf [i]='_';}; i++;
+ if (flags & CHANNEL_TIMER_FEV) {buf[i] = 'T';} else {buf [i]='_';}; i++;
+ if (flags & CHANNEL_HAS_MORE_DATA) {buf[i] = 'H';} else {buf [i]='_';}; i++;
+ buf [i] ='\0';
+
+ fprintf (stderr,"%s: %s\n", str, buf); fflush(stderr);
+ return 0;
+}
+#endif