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authordgp <dgp@users.sourceforge.net>2014-06-24 16:34:05 (GMT)
committerdgp <dgp@users.sourceforge.net>2014-06-24 16:34:05 (GMT)
commitb590e079873c15af1b48b4a05ba3d7db5926b9d7 (patch)
tree1628ef3c1fa130053f5d2588b73dd42d7ff6adc0
parent2b8bf1a9f78976b319f00258e80ed4c3fe467e50 (diff)
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Simplify / refactor Tcl_ReadRaw(). No need for CopyBuffer().
-rw-r--r--generic/tclIO.c177
1 files changed, 50 insertions, 127 deletions
diff --git a/generic/tclIO.c b/generic/tclIO.c
index 308e7a9..c2a705c 100644
--- a/generic/tclIO.c
+++ b/generic/tclIO.c
@@ -178,7 +178,6 @@ static void CleanupChannelHandlers(Tcl_Interp *interp,
static int CloseChannel(Tcl_Interp *interp, Channel *chanPtr,
int errorCode);
static void CommonGetsCleanup(Channel *chanPtr);
-static int CopyBuffer(Channel *chanPtr, char *result, int space);
static int CopyData(CopyState *csPtr, int mask);
static void CopyEventProc(ClientData clientData, int mask);
static void CreateScriptRecord(Tcl_Interp *interp,
@@ -4983,63 +4982,77 @@ Tcl_Read(
int
Tcl_ReadRaw(
Tcl_Channel chan, /* The channel from which to read. */
- char *bufPtr, /* Where to store input read. */
+ char *readBuf, /* Where to store input read. */
int bytesToRead) /* Maximum number of bytes to read. */
{
Channel *chanPtr = (Channel *) chan;
ChannelState *statePtr = chanPtr->state;
/* State info for channel */
- int nread, copied, copiedNow = INT_MAX;
-
- /*
- * 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
- * fail with 'file busy' error instead of retrieving and transforming the
- * data to copy.
- *
- * We let the check procedure now believe that there is no fcopy in
- * progress. A better solution than this might be an additional flag
- * argument to switch off specific checks.
- */
+ int copied = 0;
if (CheckChannelErrors(statePtr, TCL_READABLE | CHANNEL_RAW_MODE) != 0) {
return -1;
}
- /*
- * Check for information in the push-back buffers. If there is some, use
- * it. Go to the driver only if there is none (anymore) and the caller
- * requests more bytes.
- */
+ /* First read bytes from the push-back buffers. */
- Tcl_Preserve(chanPtr);
- for (copied = 0; bytesToRead > 0 && copiedNow > 0;
- bufPtr+=copiedNow, bytesToRead-=copiedNow, copied+=copiedNow) {
- copiedNow = CopyBuffer(chanPtr, bufPtr, bytesToRead);
+ while (chanPtr->inQueueHead && bytesToRead > 0) {
+ ChannelBuffer *bufPtr = chanPtr->inQueueHead;
+ int bytesInBuffer = BytesLeft(bufPtr);
+ int toCopy = (bytesInBuffer < bytesToRead) ? bytesInBuffer
+ : bytesToRead;
+
+ /* Copy the current chunk into the read buffer. */
+
+ memcpy(readBuf, RemovePoint(bufPtr), (size_t) toCopy);
+ bufPtr->nextRemoved += toCopy;
+ copied += toCopy;
+ readBuf += toCopy;
+ bytesToRead -= toCopy;
+
+ /* If the current buffer is empty recycle it. */
+
+ if (IsBufferEmpty(bufPtr)) {
+ chanPtr->inQueueHead = bufPtr->nextPtr;
+ if (chanPtr->inQueueHead == NULL) {
+ chanPtr->inQueueTail = NULL;
+ }
+ RecycleBuffer(chanPtr->state, bufPtr, 0);
+ }
}
+ /* Go to the driver if more data needed. */
+
if (bytesToRead > 0) {
- /*
- * Now go to the driver to get as much as is possible to
- * fill the remaining request. Since we're directly filling
- * the caller's buffer, retain the blocked flag.
- */
- nread = ChanRead(chanPtr, bufPtr, bytesToRead);
- if (nread < 0) {
+ int nread = ChanRead(chanPtr, readBuf+copied, bytesToRead);
+
+ if (nread > 0) {
+ /* Successful read (short is OK) - add to bytes copied */
+ copied += nread;
+ } else if (nread < 0) {
+ /*
+ * An error signaled. If CHANNEL_BLOCKED, then the error
+ * is not real, but an indication of blocked state. In
+ * that case, retain the flag and let caller receive the
+ * short read of copied bytes from the pushback.
+ * HOWEVER, if copied==0 bytes from pushback then repeat
+ * signalling the blocked state as an error to caller so
+ * there is no false report of an EOF.
+ * When !CHANNEL_BLOCKED, the error is real and passes on
+ * to caller.
+ */
if (!GotFlag(statePtr, CHANNEL_BLOCKED) || copied == 0) {
copied = -1;
}
- } else {
- copied += nread;
- }
- if (copied != 0) {
+ } else if (copied > 0) {
+ /*
+ * nread == 0. Driver is at EOF, but if copied>0 bytes
+ * from pushback, then we should not signal it yet.
+ */
ResetFlag(statePtr, CHANNEL_EOF);
}
}
-
- Tcl_Release(chanPtr);
return copied;
}
@@ -8941,96 +8954,6 @@ DoRead(
/*
*----------------------------------------------------------------------
*
- * CopyBuffer --
- *
- * Copy at most one buffer of input to the result space.
- *
- * Results:
- * Number of bytes stored in the result buffer. May return zero if no
- * input is available.
- *
- * Side effects:
- * Consumes buffered input. May deallocate one buffer.
- *
- *----------------------------------------------------------------------
- */
-
-static int
-CopyBuffer(
- Channel *chanPtr, /* Channel from which to read input. */
- char *result, /* Where to store the copied input. */
- int space) /* How many bytes are available in result to
- * store the copied input? */
-{
- ChannelBuffer *bufPtr; /* The buffer from which to copy bytes. */
- int bytesInBuffer; /* How many bytes are available to be copied
- * in the current input buffer? */
- int copied; /* How many characters were already copied
- * into the destination space? */
-
- /*
- * If there is no input at all, return zero. The invariant is that either
- * there is no buffer in the queue, or if the first buffer is empty, it is
- * also the last buffer (and thus there is no input in the queue). Note
- * also that if the buffer is empty, we don't leave it in the queue, but
- * recycle it.
- */
-
- if (chanPtr->inQueueHead == NULL) {
- return 0;
- }
- bufPtr = chanPtr->inQueueHead;
- bytesInBuffer = BytesLeft(bufPtr);
-
- copied = 0;
-
- if (bytesInBuffer == 0) {
- RecycleBuffer(chanPtr->state, bufPtr, 0);
- chanPtr->inQueueHead = NULL;
- chanPtr->inQueueTail = NULL;
- return 0;
- }
-
- /*
- * Copy the current chunk into the result buffer.
- */
-
- if (bytesInBuffer < space) {
- space = bytesInBuffer;
- }
-
- memcpy(result, RemovePoint(bufPtr), (size_t) space);
- bufPtr->nextRemoved += space;
- copied = space;
-
- /*
- * We don't care about in-stream EOF characters here as the data read here
- * may still flow through one or more transformations, i.e. is not in its
- * final state yet.
- */
-
- /*
- * If the current buffer is empty recycle it.
- */
-
- if (IsBufferEmpty(bufPtr)) {
- chanPtr->inQueueHead = bufPtr->nextPtr;
- if (chanPtr->inQueueHead == NULL) {
- chanPtr->inQueueTail = NULL;
- }
- RecycleBuffer(chanPtr->state, bufPtr, 0);
- }
-
- /*
- * Return the number of characters copied into the result buffer.
- */
-
- return copied;
-}
-
-/*
- *----------------------------------------------------------------------
- *
* CopyEventProc --
*
* This routine is invoked as a channel event handler for the background