A bit more readability refactoring.

2 files changed, 300 insertions, 278 deletions

diff --git a/ChangeLog b/ChangeLog
index 35d07d8..fd9fdef 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,9 @@
+2008-12-09  Donal K. Fellows  <dkf@users.sf.net>
+
+	* generic/tclIO.c (ChanClose,ChanRead,...): Factored out some of the
+	code to connect to channel drivers that was common in multiple
+	locations so as to make code more readable.
+
 2008-12-06  Donal K. Fellows  <dkf@users.sf.net>
 
 	* generic/tclCmdAH.c (FileTempfileCmd): Force temporary files to be
diff --git a/generic/tclIO.c b/generic/tclIO.c
index e6e11d0..1a2bbfb 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 1.151 2008/12/02 18:23:25 andreas_kupries Exp $
+ * RCS: @(#) $Id: tclIO.c,v 1.152 2008/12/09 14:09:14 dkf Exp $
  */
 
 #include "tclInt.h"
@@ -162,21 +162,21 @@ static void		CutChannel(Tcl_Channel chan);
  * --------------------------------------------------------------------------
  */
 
-#define BytesLeft(bufPtr) ((bufPtr)->nextAdded - (bufPtr)->nextRemoved)
+#define BytesLeft(bufPtr)	((bufPtr)->nextAdded - (bufPtr)->nextRemoved)
 
-#define SpaceLeft(bufPtr) ((bufPtr)->bufLength - (bufPtr)->nextAdded)
+#define SpaceLeft(bufPtr)	((bufPtr)->bufLength - (bufPtr)->nextAdded)
 
-#define IsBufferReady(bufPtr) ((bufPtr)->nextAdded > (bufPtr)->nextRemoved)
+#define IsBufferReady(bufPtr)	((bufPtr)->nextAdded > (bufPtr)->nextRemoved)
 
-#define IsBufferEmpty(bufPtr) ((bufPtr)->nextAdded == (bufPtr)->nextRemoved)
+#define IsBufferEmpty(bufPtr)	((bufPtr)->nextAdded == (bufPtr)->nextRemoved)
 
-#define IsBufferFull(bufPtr) ((bufPtr)->nextAdded >= (bufPtr)->bufLength)
+#define IsBufferFull(bufPtr)	((bufPtr)->nextAdded >= (bufPtr)->bufLength)
 
-#define IsBufferOverflowing(bufPtr) ((bufPtr)->nextAdded > (bufPtr)->bufLength)
+#define IsBufferOverflowing(bufPtr) ((bufPtr)->nextAdded>(bufPtr)->bufLength)
 
-#define InsertPoint(bufPtr) ((bufPtr)->buf + (bufPtr)->nextAdded)
+#define InsertPoint(bufPtr)	((bufPtr)->buf + (bufPtr)->nextAdded)
 
-#define RemovePoint(bufPtr) ((bufPtr)->buf + (bufPtr)->nextRemoved)
+#define RemovePoint(bufPtr)	((bufPtr)->buf + (bufPtr)->nextRemoved)
 
 /*
  * For working with channel state flag bits.
@@ -184,6 +184,7 @@ static void		CutChannel(Tcl_Channel chan);
 
 #define SetFlag(statePtr, flag)		((statePtr)->flags |= (flag))
 #define ResetFlag(statePtr, flag)	((statePtr)->flags &= ~(flag))
+#define GotFlag(statePtr, flag)		((statePtr)->flags & (flag))
 
 /*
  * Macro for testing whether a string (in optionName, length len) matches a
@@ -204,7 +205,8 @@ static void		CutChannel(Tcl_Channel chan);
  */
 
 static void		DupChannelIntRep(Tcl_Obj *objPtr, Tcl_Obj *copyPtr);
-static int		SetChannelFromAny(Tcl_Interp *interp, Tcl_Obj *objPtr);
+static int		SetChannelFromAny(Tcl_Interp *interp,
+			    Tcl_Obj *objPtr);
 static void		UpdateStringOfChannel(Tcl_Obj *objPtr);
 static void		FreeChannelIntRep(Tcl_Obj *objPtr);
 
@@ -230,6 +232,100 @@ static const Tcl_ObjType tclChannelType = {
 /*
  *---------------------------------------------------------------------------
  *
+ * ChanClose, ChanRead, ChanSeek, ChanThreadAction, ChanWatch, ChanWrite --
+ *
+ *	Simplify the access to selected channel driver "methods" that are used
+ *	in multiple places in a stereotypical fashion. These are just thin
+ *	wrappers around the driver functions.
+ *
+ *---------------------------------------------------------------------------
+ */
+
+static inline int
+ChanClose(
+    Channel *chanPtr,
+    Tcl_Interp *interp)
+{
+    if (chanPtr->typePtr->closeProc != TCL_CLOSE2PROC) {
+	return chanPtr->typePtr->closeProc(chanPtr->instanceData, interp);
+    } else {
+	return chanPtr->typePtr->close2Proc(chanPtr->instanceData, interp, 0);
+    }
+}
+
+static inline int
+ChanRead(
+    Channel *chanPtr,
+    char *dst,
+    int dstSize,
+    int *errnoPtr)
+{
+    return chanPtr->typePtr->inputProc(chanPtr->instanceData, dst, dstSize,
+	    errnoPtr);
+}
+
+static inline Tcl_WideInt
+ChanSeek(
+    Channel *chanPtr,
+    Tcl_WideInt offset,
+    int mode,
+    int *errnoPtr)
+{
+    /*
+     * Note that we prefer the wideSeekProc if that field is available in the
+     * type and non-NULL.
+     */
+
+    if (HaveVersion(chanPtr->typePtr, TCL_CHANNEL_VERSION_3) &&
+	    chanPtr->typePtr->wideSeekProc != NULL) {
+	return chanPtr->typePtr->wideSeekProc(chanPtr->instanceData,
+		offset, mode, errnoPtr);
+    }
+
+    if (offset<Tcl_LongAsWide(LONG_MIN) || offset>Tcl_LongAsWide(LONG_MAX)) {
+	*errnoPtr = EOVERFLOW;
+	return Tcl_LongAsWide(-1);
+    }
+
+    return Tcl_LongAsWide(chanPtr->typePtr->seekProc(chanPtr->instanceData,
+	    Tcl_WideAsLong(offset), mode, errnoPtr));
+}
+
+static inline void
+ChanThreadAction(
+    Channel *chanPtr,
+    int action)
+{
+    Tcl_DriverThreadActionProc *threadActionProc =
+	    Tcl_ChannelThreadActionProc(chanPtr->typePtr);
+
+    if (threadActionProc != NULL) {
+	threadActionProc(chanPtr->instanceData, action);
+    }
+}
+
+static inline void
+ChanWatch(
+    Channel *chanPtr,
+    int mask)
+{
+    chanPtr->typePtr->watchProc(chanPtr->instanceData, mask);
+}
+
+static inline int
+ChanWrite(
+    Channel *chanPtr,
+    const char *src,
+    int srcLen,
+    int *errnoPtr)
+{
+    return chanPtr->typePtr->outputProc(chanPtr->instanceData, src, srcLen,
+	    errnoPtr);
+}
+
+/*
+ *---------------------------------------------------------------------------
+ *
  * TclInitIOSubsystem --
  *
  *	Initialize all resources used by this subsystem on a per-process
@@ -299,7 +395,8 @@ TclFinalizeIOSubsystem(void)
 		statePtr != NULL;
 		statePtr = statePtr->nextCSPtr) {
 	    chanPtr = statePtr->topChanPtr;
-	    if (!(statePtr->flags & (CHANNEL_INCLOSE|CHANNEL_CLOSED|CHANNEL_DEAD))) {
+	    if (!GotFlag(statePtr, CHANNEL_INCLOSE | CHANNEL_CLOSED |
+		    CHANNEL_DEAD)) {
 		active = 1;
 		break;
 	    }
@@ -349,12 +446,7 @@ TclFinalizeIOSubsystem(void)
 		 * device for this channel.
 		 */
 
-		if (chanPtr->typePtr->closeProc != TCL_CLOSE2PROC) {
-		    chanPtr->typePtr->closeProc(chanPtr->instanceData, NULL);
-		} else {
-		    chanPtr->typePtr->close2Proc(chanPtr->instanceData, NULL,
-			    0);
-		}
+		(void) ChanClose(chanPtr, NULL);
 
 		/*
 		 * Finally, we clean up the fields in the channel data
@@ -396,6 +488,7 @@ Tcl_SetStdChannel(
     int type)			/* One of TCL_STDIN, TCL_STDOUT, TCL_STDERR. */
 {
     ThreadSpecificData *tsdPtr = TCL_TSD_INIT(&dataKey);
+
     switch (type) {
     case TCL_STDIN:
 	tsdPtr->stdinInitialized = 1;
@@ -687,7 +780,7 @@ DeleteChannelTable(
 		}
 
 		Tcl_DeleteChannelHandler((Tcl_Channel) chanPtr,
-			TclChannelEventScriptInvoker, (ClientData) sPtr);
+			TclChannelEventScriptInvoker, sPtr);
 
 		TclDecrRefCount(sPtr->scriptPtr);
 		ckfree((char *) sPtr);
@@ -707,7 +800,7 @@ DeleteChannelTable(
 	SetFlag(statePtr, CHANNEL_TAINTED);
 	statePtr->refCount--;
 	if (statePtr->refCount <= 0) {
-	    if (!(statePtr->flags & BG_FLUSH_SCHEDULED)) {
+	    if (!GotFlag(statePtr, BG_FLUSH_SCHEDULED)) {
 		(void) Tcl_Close(interp, (Tcl_Channel) chanPtr);
 	    }
 	}
@@ -746,21 +839,19 @@ CheckForStdChannelsBeingClosed(
     ChannelState *statePtr = ((Channel *) chan)->state;
     ThreadSpecificData *tsdPtr = TCL_TSD_INIT(&dataKey);
 
-    if ((chan == tsdPtr->stdinChannel) && (tsdPtr->stdinInitialized)) {
+    if ((chan == tsdPtr->stdinChannel) && tsdPtr->stdinInitialized) {
 	if (statePtr->refCount < 2) {
 	    statePtr->refCount = 0;
 	    tsdPtr->stdinChannel = NULL;
 	    return;
 	}
-    } else if ((chan == tsdPtr->stdoutChannel)
-	    && (tsdPtr->stdoutInitialized)) {
+    } else if ((chan == tsdPtr->stdoutChannel) && tsdPtr->stdoutInitialized) {
 	if (statePtr->refCount < 2) {
 	    statePtr->refCount = 0;
 	    tsdPtr->stdoutChannel = NULL;
 	    return;
 	}
-    } else if ((chan == tsdPtr->stderrChannel)
-	    && (tsdPtr->stderrInitialized)) {
+    } else if ((chan == tsdPtr->stderrChannel) && tsdPtr->stderrInitialized) {
 	if (statePtr->refCount < 2) {
 	    statePtr->refCount = 0;
 	    tsdPtr->stderrChannel = NULL;
@@ -894,7 +985,7 @@ Tcl_UnregisterChannel(
 
     statePtr = ((Channel *) chan)->state->bottomChanPtr->state;
 
-    if (statePtr->flags & CHANNEL_INCLOSE) {
+    if (GotFlag(statePtr, CHANNEL_INCLOSE)) {
 	if (interp != NULL) {
 	    Tcl_AppendResult(interp, "Illegal recursive call to close "
 		    "through close-handler of channel", NULL);
@@ -933,12 +1024,12 @@ Tcl_UnregisterChannel(
 	    SetFlag(statePtr, BUFFER_READY);
 	}
 	Tcl_Preserve(statePtr);
-	if (!(statePtr->flags & BG_FLUSH_SCHEDULED)) {
+	if (!GotFlag(statePtr, BG_FLUSH_SCHEDULED)) {
 	    /*
 	     * We don't want to re-enter Tcl_Close().
 	     */
 
-	    if (!(statePtr->flags & CHANNEL_CLOSED)) {
+	    if (!GotFlag(statePtr, CHANNEL_CLOSED)) {
 		if (Tcl_Close(interp, chan) != TCL_OK) {
 		    SetFlag(statePtr, CHANNEL_CLOSED);
 		    Tcl_Release(statePtr);
@@ -1147,7 +1238,7 @@ Tcl_GetChannel(
     chanPtr = Tcl_GetHashValue(hPtr);
     chanPtr = chanPtr->state->bottomChanPtr;
     if (modePtr != NULL) {
-	*modePtr = (chanPtr->state->flags & (TCL_READABLE|TCL_WRITABLE));
+	*modePtr = chanPtr->state->flags & (TCL_READABLE|TCL_WRITABLE);
     }
 
     return (Tcl_Channel) chanPtr;
@@ -1192,10 +1283,10 @@ TclGetChannelFromObj(
     }
 
     statePtr = GET_CHANNELSTATE(objPtr);
-    *channelPtr = (Tcl_Channel) (statePtr->bottomChanPtr);
+    *channelPtr = (Tcl_Channel) statePtr->bottomChanPtr;
 
     if (modePtr != NULL) {
-	*modePtr = (statePtr->flags & (TCL_READABLE|TCL_WRITABLE));
+	*modePtr = statePtr->flags & (TCL_READABLE|TCL_WRITABLE);
     }
 
     return TCL_OK;
@@ -1241,7 +1332,7 @@ Tcl_CreateChannel(
      * as well.
      */
 
-    assert(sizeof(Tcl_ChannelTypeVersion) == sizeof(Tcl_DriverBlockModeProc*));
+    assert(sizeof(Tcl_ChannelTypeVersion)==sizeof(Tcl_DriverBlockModeProc *));
 
     /*
      * JH: We could subsequently memset these to 0 to avoid the numerous
@@ -1322,9 +1413,8 @@ Tcl_CreateChannel(
     statePtr->csPtrW		= NULL;
 
     statePtr->outputStage	= NULL;
-    if ((statePtr->encoding != NULL) && (statePtr->flags & TCL_WRITABLE)) {
-	statePtr->outputStage = (char *)
-		ckalloc((unsigned) (statePtr->bufSize + 2));
+    if ((statePtr->encoding != NULL) && GotFlag(statePtr, TCL_WRITABLE)) {
+	statePtr->outputStage = ckalloc((unsigned) statePtr->bufSize + 2);
     }
 
     /*
@@ -1415,7 +1505,8 @@ Tcl_CreateChannel(
 Tcl_Channel
 Tcl_StackChannel(
     Tcl_Interp *interp,		/* The interpreter we are working in */
-    const Tcl_ChannelType *typePtr,	/* The channel type record for the new
+    const Tcl_ChannelType *typePtr,
+				/* The channel type record for the new
 				 * channel. */
     ClientData instanceData,	/* Instance specific data for the new
 				 * channel. */
@@ -1426,7 +1517,6 @@ Tcl_StackChannel(
     ThreadSpecificData *tsdPtr = TCL_TSD_INIT(&dataKey);
     Channel *chanPtr, *prevChanPtr;
     ChannelState *statePtr;
-    Tcl_DriverThreadActionProc *threadActionProc;
 
     /*
      * Find the given channel (prevChan) in the list of all channels. If we do
@@ -1480,13 +1570,10 @@ Tcl_StackChannel(
      */
 
     if ((mask & TCL_WRITABLE) != 0) {
-        CopyState *csPtrR;
-        CopyState *csPtrW;
+	CopyState *csPtrR = statePtr->csPtrR;
+	CopyState *csPtrW = statePtr->csPtrW;
 
-        csPtrR           = statePtr->csPtrR;
 	statePtr->csPtrR = NULL;
-
-        csPtrW           = statePtr->csPtrW;
 	statePtr->csPtrW = NULL;
 
 	if (Tcl_Flush((Tcl_Channel) prevChanPtr) != TCL_OK) {
@@ -1571,10 +1658,7 @@ Tcl_StackChannel(
      * time, mangling it.
      */
 
-    threadActionProc = Tcl_ChannelThreadActionProc(chanPtr->typePtr);
-    if (threadActionProc != NULL) {
-	threadActionProc(chanPtr->instanceData, TCL_CHANNEL_THREAD_INSERT);
-    }
+    ChanThreadAction(chanPtr, TCL_CHANNEL_THREAD_INSERT);
 
     return (Tcl_Channel) chanPtr;
 }
@@ -1605,7 +1689,6 @@ Tcl_UnstackChannel(
     Channel *chanPtr = (Channel *) chan;
     ChannelState *statePtr = chanPtr->state;
     int result = 0;
-    Tcl_DriverThreadActionProc *threadActionProc;
 
     /*
      * This operation should occur at the top of a channel stack.
@@ -1631,14 +1714,11 @@ Tcl_UnstackChannel(
 	 * CheckForChannelErrors inside.
 	 */
 
-	if (statePtr->flags & TCL_WRITABLE) {
-	    CopyState *csPtrR;
-	    CopyState *csPtrW;
+	if (GotFlag(statePtr, TCL_WRITABLE)) {
+	    CopyState *csPtrR = statePtr->csPtrR;
+	    CopyState *csPtrW = statePtr->csPtrW;
 
-	    csPtrR           = statePtr->csPtrR;
 	    statePtr->csPtrR = NULL;
-
-	    csPtrW           = statePtr->csPtrW;
 	    statePtr->csPtrW = NULL;
 
 	    if (Tcl_Flush((Tcl_Channel) chanPtr) != TCL_OK) {
@@ -1675,16 +1755,14 @@ Tcl_UnstackChannel(
 	 * 'DiscardInputQueued' on that.
 	 */
 
-	if ((((statePtr->flags & TCL_READABLE) != 0)) &&
+	if (GotFlag(statePtr, TCL_READABLE) &&
 		((statePtr->inQueueHead != NULL) ||
 		(chanPtr->inQueueHead != NULL))) {
-
 	    if ((statePtr->inQueueHead != NULL) &&
 		    (chanPtr->inQueueHead != NULL)) {
 		statePtr->inQueueTail->nextPtr = chanPtr->inQueueHead;
 		statePtr->inQueueTail = chanPtr->inQueueTail;
 		statePtr->inQueueHead = statePtr->inQueueTail;
-
 	    } else if (chanPtr->inQueueHead != NULL) {
 		statePtr->inQueueHead = chanPtr->inQueueHead;
 		statePtr->inQueueTail = chanPtr->inQueueTail;
@@ -1708,10 +1786,7 @@ Tcl_UnstackChannel(
 	 * the state which are still active.
 	 */
 
-	threadActionProc = Tcl_ChannelThreadActionProc(chanPtr->typePtr);
-	if (threadActionProc != NULL) {
-	    threadActionProc(chanPtr->instanceData,TCL_CHANNEL_THREAD_REMOVE);
-	}
+	ChanThreadAction(chanPtr, TCL_CHANNEL_THREAD_REMOVE);
 
 	statePtr->topChanPtr = downChanPtr;
 	downChanPtr->upChanPtr = NULL;
@@ -1725,14 +1800,7 @@ Tcl_UnstackChannel(
 	 * Close and free the channel driver state.
 	 */
 
-	if (chanPtr->typePtr->closeProc != TCL_CLOSE2PROC) {
-	    result = chanPtr->typePtr->closeProc(chanPtr->instanceData,
-		    interp);
-	} else {
-	    result = chanPtr->typePtr->close2Proc(chanPtr->instanceData,
-		    interp, 0);
-	}
-
+	result = ChanClose(chanPtr, interp);
 	chanPtr->typePtr = NULL;
 
 	/*
@@ -1967,9 +2035,9 @@ const char *
 Tcl_GetChannelName(
     Tcl_Channel chan)		/* The channel for which to return the name. */
 {
-    ChannelState *statePtr;	/* State of actual channel. */
+    ChannelState *statePtr = ((Channel *) chan)->state;
+				/* State of actual channel. */
 
-    statePtr = ((Channel *) chan)->state;
     return statePtr->channelName;
 }
 
@@ -2099,7 +2167,7 @@ RecycleBuffer(
      * Only save buffers for the input queue if the channel is readable.
      */
 
-    if (statePtr->flags & TCL_READABLE) {
+    if (GotFlag(statePtr, TCL_READABLE)) {
 	if (statePtr->inQueueHead == NULL) {
 	    statePtr->inQueueHead = bufPtr;
 	    statePtr->inQueueTail = bufPtr;
@@ -2115,7 +2183,7 @@ RecycleBuffer(
      * Only save buffers for the output queue if the channel is writable.
      */
 
-    if (statePtr->flags & TCL_WRITABLE) {
+    if (GotFlag(statePtr, TCL_WRITABLE)) {
 	if (statePtr->curOutPtr == NULL) {
 	    statePtr->curOutPtr = bufPtr;
 	    goto keepBuffer;
@@ -2188,15 +2256,16 @@ CheckForDeadChannel(
     Tcl_Interp *interp,		/* For error reporting (can be NULL) */
     ChannelState *statePtr)	/* The channel state to check. */
 {
-    if (statePtr->flags & CHANNEL_DEAD) {
-	Tcl_SetErrno(EINVAL);
-	if (interp) {
-	    Tcl_AppendResult(interp,
-		    "unable to access channel: invalid channel", NULL);
-	}
-	return 1;
+    if (!GotFlag(statePtr, CHANNEL_DEAD)) {
+	return 0;
     }
-    return 0;
+
+    Tcl_SetErrno(EINVAL);
+    if (interp) {
+	Tcl_AppendResult(interp, "unable to access channel: invalid channel",
+		NULL);
+    }
+    return 1;
 }
 
 /*
@@ -2264,7 +2333,7 @@ FlushChannel(
 
 	if (((statePtr->curOutPtr != NULL) &&
 		IsBufferFull(statePtr->curOutPtr))
-		|| ((statePtr->flags & BUFFER_READY) &&
+		|| (GotFlag(statePtr, BUFFER_READY) &&
 			(statePtr->outQueueHead == NULL))) {
 	    ResetFlag(statePtr, BUFFER_READY);
 	    statePtr->curOutPtr->nextPtr = NULL;
@@ -2283,8 +2352,7 @@ FlushChannel(
 	 * is active, we just return without producing any output.
 	 */
 
-	if ((!calledFromAsyncFlush) &&
-		(statePtr->flags & BG_FLUSH_SCHEDULED)) {
+	if (!calledFromAsyncFlush && GotFlag(statePtr, BG_FLUSH_SCHEDULED)) {
 	    return 0;
 	}
 
@@ -2293,7 +2361,7 @@ FlushChannel(
 	 */
 
 	if (bufPtr == NULL) {
-	    break;	/* Out of the "while (1)". */
+	    break;		/* Out of the "while (1)". */
 	}
 
 	/*
@@ -2301,8 +2369,7 @@ FlushChannel(
 	 */
 
 	toWrite = BytesLeft(bufPtr);
-	written = chanPtr->typePtr->outputProc(chanPtr->instanceData,
-		RemovePoint(bufPtr), toWrite, &errorCode);
+	written = ChanWrite(chanPtr, RemovePoint(bufPtr),toWrite, &errorCode);
 
 	/*
 	 * If the write failed completely attempt to start the asynchronous
@@ -2333,7 +2400,7 @@ FlushChannel(
 		 * it's a tty channel (dup'ed underneath)
 		 */
 
-		if (!(statePtr->flags & BG_FLUSH_SCHEDULED)) {
+		if (!GotFlag(statePtr, BG_FLUSH_SCHEDULED)) {
 		    SetFlag(statePtr, BG_FLUSH_SCHEDULED);
 		    UpdateInterest(chanPtr);
 		}
@@ -2383,7 +2450,8 @@ FlushChannel(
 		Tcl_SetErrno(errorCode);
 		if (interp != NULL && !TclChanCaughtErrorBypass(interp,
 			(Tcl_Channel) chanPtr)) {
-		    Tcl_SetObjResult(interp, Tcl_NewStringObj(Tcl_PosixError(interp), -1));
+		    Tcl_SetObjResult(interp,
+			    Tcl_NewStringObj(Tcl_PosixError(interp), -1));
 		}
 
 		/*
@@ -2425,13 +2493,12 @@ FlushChannel(
      * data has been flushed at the system level.
      */
 
-    if (statePtr->flags & BG_FLUSH_SCHEDULED) {
+    if (GotFlag(statePtr, BG_FLUSH_SCHEDULED)) {
 	if (wroteSome) {
 	    return errorCode;
 	} else if (statePtr->outQueueHead == NULL) {
 	    ResetFlag(statePtr, BG_FLUSH_SCHEDULED);
-	    chanPtr->typePtr->watchProc(chanPtr->instanceData,
-		    statePtr->interestMask);
+	    ChanWatch(chanPtr, statePtr->interestMask);
 	}
     }
 
@@ -2441,7 +2508,7 @@ FlushChannel(
      * current output buffer.
      */
 
-    if ((statePtr->flags & CHANNEL_CLOSED) && (statePtr->refCount <= 0) &&
+    if (GotFlag(statePtr, CHANNEL_CLOSED) && (statePtr->refCount <= 0) &&
 	    (statePtr->outQueueHead == NULL) &&
 	    ((statePtr->curOutPtr == NULL) ||
 	    IsBufferEmpty(statePtr->curOutPtr))) {
@@ -2517,11 +2584,11 @@ CloseChannel(
      * device.
      */
 
-    if ((statePtr->outEofChar != 0) && (statePtr->flags & TCL_WRITABLE)) {
+    if ((statePtr->outEofChar != 0) && GotFlag(statePtr, TCL_WRITABLE)) {
 	int dummy;
 	char c = (char) statePtr->outEofChar;
 
-	chanPtr->typePtr->outputProc(chanPtr->instanceData, &c, 1, &dummy);
+	(void) ChanWrite(chanPtr, &c, 1, &dummy);
     }
 
     /*
@@ -2549,12 +2616,7 @@ CloseChannel(
      * This may leave a TIP #219 error message in the interp.
      */
 
-    if (chanPtr->typePtr->closeProc != TCL_CLOSE2PROC) {
-	result = chanPtr->typePtr->closeProc(chanPtr->instanceData, interp);
-    } else {
-	result = chanPtr->typePtr->close2Proc(chanPtr->instanceData, interp,
-		0);
-    }
+    result = ChanClose(chanPtr, interp);
 
     /*
      * Some resources can be cleared only if the bottom channel in a stack is
@@ -2678,7 +2740,6 @@ CutChannel(
 				 * the list on close. */
     ChannelState *statePtr = ((Channel *) chan)->state;
 				/* State of the channel stack. */
-    Tcl_DriverThreadActionProc *threadActionProc;
 
     /*
      * Remove this channel from of the list of all channels (in the current
@@ -2705,11 +2766,7 @@ CutChannel(
      * TIP #218, Channel Thread Actions
      */
 
-    threadActionProc = Tcl_ChannelThreadActionProc(Tcl_GetChannelType(chan));
-    if (threadActionProc != NULL) {
-	threadActionProc(Tcl_GetChannelInstanceData(chan),
-		TCL_CHANNEL_THREAD_REMOVE);
-    }
+    ChanThreadAction((Channel *) chan, TCL_CHANNEL_THREAD_REMOVE);
 }
 
 void
@@ -2724,7 +2781,6 @@ Tcl_CutChannel(
 				 * the list on close. */
     ChannelState *statePtr = chanPtr->state;
 				/* State of the channel stack. */
-    Tcl_DriverThreadActionProc *threadActionProc;
 
     /*
      * Remove this channel from of the list of all channels (in the current
@@ -2752,12 +2808,8 @@ Tcl_CutChannel(
      * For all transformations and the base channel.
      */
 
-    while (chanPtr) {
-	threadActionProc = Tcl_ChannelThreadActionProc(chanPtr->typePtr);
-	if (threadActionProc != NULL) {
-	    threadActionProc(chanPtr->instanceData,TCL_CHANNEL_THREAD_REMOVE);
-	}
-	chanPtr= chanPtr->upChanPtr;
+    for (; chanPtr != NULL ; chanPtr = chanPtr->upChanPtr) {
+	ChanThreadAction(chanPtr, TCL_CHANNEL_THREAD_REMOVE);
     }
 }
 
@@ -2794,7 +2846,6 @@ SpliceChannel(
 {
     ThreadSpecificData *tsdPtr = TCL_TSD_INIT(&dataKey);
     ChannelState *statePtr = ((Channel *) chan)->state;
-    Tcl_DriverThreadActionProc *threadActionProc;
 
     if (statePtr->nextCSPtr != NULL) {
 	Tcl_Panic("SpliceChannel: trying to add channel used in different list");
@@ -2815,11 +2866,7 @@ SpliceChannel(
      * TIP #218, Channel Thread Actions
      */
 
-    threadActionProc = Tcl_ChannelThreadActionProc(Tcl_GetChannelType(chan));
-    if (threadActionProc != NULL) {
-	threadActionProc(Tcl_GetChannelInstanceData(chan),
-		TCL_CHANNEL_THREAD_INSERT);
-    }
+    ChanThreadAction((Channel *) chan, TCL_CHANNEL_THREAD_INSERT);
 }
 
 void
@@ -2830,7 +2877,6 @@ Tcl_SpliceChannel(
     Channel *chanPtr = ((Channel *) chan)->state->bottomChanPtr;
     ThreadSpecificData *tsdPtr = TCL_TSD_INIT(&dataKey);
     ChannelState *statePtr = chanPtr->state;
-    Tcl_DriverThreadActionProc *threadActionProc;
 
     if (statePtr->nextCSPtr != NULL) {
 	Tcl_Panic("SpliceChannel: trying to add channel used in different list");
@@ -2852,12 +2898,8 @@ Tcl_SpliceChannel(
      * For all transformations and the base channel.
      */
 
-    while (chanPtr) {
-	threadActionProc = Tcl_ChannelThreadActionProc(chanPtr->typePtr);
-	if (threadActionProc != NULL) {
-	    threadActionProc(chanPtr->instanceData,TCL_CHANNEL_THREAD_INSERT);
-	}
-	chanPtr= chanPtr->upChanPtr;
+    for (; chanPtr != NULL ; chanPtr = chanPtr->upChanPtr) {
+	ChanThreadAction(chanPtr, TCL_CHANNEL_THREAD_INSERT);
     }
 }
 
@@ -2923,7 +2965,7 @@ Tcl_Close(
 	Tcl_Panic("called Tcl_Close on channel with refCount > 0");
     }
 
-    if (statePtr->flags & CHANNEL_INCLOSE) {
+    if (GotFlag(statePtr, CHANNEL_INCLOSE)) {
 	if (interp) {
 	    Tcl_AppendResult(interp, "Illegal recursive call to close "
 		    "through close-handler of channel", NULL);
@@ -3219,9 +3261,7 @@ Tcl_WriteRaw(
      * The code was stolen from 'FlushChannel'.
      */
 
-    written = chanPtr->typePtr->outputProc(chanPtr->instanceData, src,
-	    srcLen, &errorCode);
-
+    written = ChanWrite(chanPtr, src, srcLen, &errorCode);
     if (written < 0) {
 	Tcl_SetErrno(errorCode);
     }
@@ -3322,12 +3362,13 @@ DoWriteChars(
 	 * be extended to more efficient translation of the src string.
 	 */
 
- 	int result;
+	int result;
 
 	if ((len == 1) && (UCHAR(*src) < 0xC0)) {
 	    result = WriteBytes(chanPtr, src, len);
 	} else {
 	    Tcl_Obj *objPtr = Tcl_NewStringObj(src, len);
+
 	    src = (char *) Tcl_GetByteArrayFromObj(objPtr, &len);
 	    result = WriteBytes(chanPtr, src, len);
 	    TclDecrRefCount(objPtr);
@@ -3427,8 +3468,8 @@ WriteBytes(
     total = 0;
     sawLF = 0;
     savedLF = 0;
-    translate = (statePtr->flags & CHANNEL_LINEBUFFERED)
-	|| (statePtr->outputTranslation != TCL_TRANSLATE_LF);
+    translate = GotFlag(statePtr, CHANNEL_LINEBUFFERED)
+	    || (statePtr->outputTranslation != TCL_TRANSLATE_LF);
 
     /*
      * Loop over all bytes in src, storing them in output buffer with proper
@@ -3537,8 +3578,8 @@ WriteChars(
 
     endEncoding = ((statePtr->outputEncodingFlags & TCL_ENCODING_END) != 0);
 
-    translate = (statePtr->flags & CHANNEL_LINEBUFFERED)
-	|| (statePtr->outputTranslation != TCL_TRANSLATE_LF);
+    translate = GotFlag(statePtr, CHANNEL_LINEBUFFERED)
+	    || (statePtr->outputTranslation != TCL_TRANSLATE_LF);
 
     /*
      * Loop over all UTF-8 characters in src, storing them in staging buffer
@@ -3561,16 +3602,17 @@ WriteChars(
 	    if (savedLF) {
 		/*
 		 * A '\n' was left over from last call to TranslateOutputEOL()
-		 * and we need to store it in the staging buffer. If the channel
-		 * is line-based, we will need to flush the output buffer (after
-		 * translating the staging buffer).
+		 * and we need to store it in the staging buffer. If the
+		 * channel is line-based, we will need to flush the output
+		 * buffer (after translating the staging buffer).
 		 */
 
 		*stage++ = '\n';
 		stageLen--;
 		sawLF++;
 	    }
-	    if (TranslateOutputEOL(statePtr, stage, src, &stageLen, &toWrite)) {
+	    if (TranslateOutputEOL(statePtr, stage, src, &stageLen,
+		    &toWrite)) {
 		sawLF++;
 	    }
 
@@ -3863,18 +3905,18 @@ CheckFlush(
      * 3. if it contains any output and this channel is unbuffered.
      */
 
-    if ((statePtr->flags & BUFFER_READY) == 0) {
+    if (!GotFlag(statePtr, BUFFER_READY)) {
 	if (IsBufferFull(bufPtr)) {
 	    SetFlag(statePtr, BUFFER_READY);
-	} else if (statePtr->flags & CHANNEL_LINEBUFFERED) {
+	} else if (GotFlag(statePtr, CHANNEL_LINEBUFFERED)) {
 	    if (newlineFlag != 0) {
 		SetFlag(statePtr, BUFFER_READY);
 	    }
-	} else if (statePtr->flags & CHANNEL_UNBUFFERED) {
+	} else if (GotFlag(statePtr, CHANNEL_UNBUFFERED)) {
 	    SetFlag(statePtr, BUFFER_READY);
 	}
     }
-    if (statePtr->flags & BUFFER_READY) {
+    if (GotFlag(statePtr, BUFFER_READY)) {
 	if (FlushChannel(NULL, chanPtr, 0) != 0) {
 	    return -1;
 	}
@@ -4125,7 +4167,7 @@ Tcl_GetsObj(
 	case TCL_TRANSLATE_AUTO:
 	    eol = dst;
 	    skip = 1;
-	    if (statePtr->flags & INPUT_SAW_CR) {
+	    if (GotFlag(statePtr, INPUT_SAW_CR)) {
 		ResetFlag(statePtr, INPUT_SAW_CR);
 		if ((eol < dstEnd) && (*eol == '\n')) {
 		    /*
@@ -4193,7 +4235,7 @@ Tcl_GetsObj(
 	    SetFlag(statePtr, CHANNEL_EOF | CHANNEL_STICKY_EOF);
 	    statePtr->inputEncodingFlags |= TCL_ENCODING_END;
 	}
-	if (statePtr->flags & CHANNEL_EOF) {
+	if (GotFlag(statePtr, CHANNEL_EOF)) {
 	    skip = 0;
 	    eol = dstEnd;
 	    if (eol == objPtr->bytes + oldLength) {
@@ -4350,7 +4392,11 @@ TclGetsObjBinary(
     skip = 0;
     eof = NULL;
     inEofChar = statePtr->inEofChar;
-    /* Only handle TCL_TRANSLATE_LF and TCL_TRANSLATE_CR */
+
+    /*
+     * Only handle TCL_TRANSLATE_LF and TCL_TRANSLATE_CR.
+     */
+
     eolChar = (statePtr->inputTranslation == TCL_TRANSLATE_LF) ? '\n' : '\r';
 
     while (1) {
@@ -4373,8 +4419,8 @@ TclGetsObjBinary(
 	     * device. Side effect is to allocate another channel buffer.
 	     */
 
-	    if (statePtr->flags & CHANNEL_BLOCKED) {
-		if (statePtr->flags & CHANNEL_NONBLOCKING) {
+	    if (GotFlag(statePtr, CHANNEL_BLOCKED)) {
+		if (GotFlag(statePtr, CHANNEL_NONBLOCKING)) {
 		    goto restore;
 		}
 		ResetFlag(statePtr, CHANNEL_BLOCKED);
@@ -4425,7 +4471,7 @@ TclGetsObjBinary(
 	    SetFlag(statePtr, CHANNEL_EOF | CHANNEL_STICKY_EOF);
 	    statePtr->inputEncodingFlags |= TCL_ENCODING_END;
 	}
-	if (statePtr->flags & CHANNEL_EOF) {
+	if (GotFlag(statePtr, CHANNEL_EOF)) {
 	    skip = 0;
 	    eol = dstEnd;
 	    if ((dst == dstEnd) && (byteLen == oldLength)) {
@@ -4624,8 +4670,8 @@ FilterInputBytes(
 	 */
 
     read:
-	if (statePtr->flags & CHANNEL_BLOCKED) {
-	    if (statePtr->flags & CHANNEL_NONBLOCKING) {
+	if (GotFlag(statePtr, CHANNEL_BLOCKED)) {
+	    if (GotFlag(statePtr, CHANNEL_NONBLOCKING)) {
 		gsPtr->charsWrote = 0;
 		gsPtr->rawRead = 0;
 		return -1;
@@ -4701,7 +4747,7 @@ FilterInputBytes(
 		 * returning those UTF-8 characters because a EOL might be
 		 * present in them.
 		 */
-	    } else if (statePtr->flags & CHANNEL_EOF) {
+	    } else if (GotFlag(statePtr, CHANNEL_EOF)) {
 		/*
 		 * There was a partial character followed by EOF on the
 		 * device. Fall through, returning that nothing was found.
@@ -4790,7 +4836,7 @@ PeekAhead(
 
 		goto cleanup;
 	    }
-	    if ((statePtr->flags & CHANNEL_NONBLOCKING) == 0) {
+	    if (!GotFlag(statePtr, CHANNEL_NONBLOCKING)) {
 		blockModeProc = Tcl_ChannelBlockModeProc(chanPtr->typePtr);
 		if (blockModeProc == NULL) {
 		    /*
@@ -4986,11 +5032,11 @@ Tcl_ReadRaw(
 	copiedNow = CopyBuffer(chanPtr, bufPtr + copied,
 		bytesToRead - copied);
 	if (copiedNow == 0) {
-	    if (statePtr->flags & CHANNEL_EOF) {
+	    if (GotFlag(statePtr, CHANNEL_EOF)) {
 		goto done;
 	    }
-	    if (statePtr->flags & CHANNEL_BLOCKED) {
-		if (statePtr->flags & CHANNEL_NONBLOCKING) {
+	    if (GotFlag(statePtr, CHANNEL_BLOCKED)) {
+		if (GotFlag(statePtr, CHANNEL_NONBLOCKING)) {
 		    goto done;
 		}
 		ResetFlag(statePtr, CHANNEL_BLOCKED);
@@ -5004,9 +5050,9 @@ Tcl_ReadRaw(
 	     * and only if we are sure to have data.
 	     */
 
-	    if ((statePtr->flags & CHANNEL_NONBLOCKING) &&
+	    if (GotFlag(statePtr, CHANNEL_NONBLOCKING) &&
 		    (Tcl_ChannelBlockModeProc(chanPtr->typePtr) == NULL) &&
-		    !(statePtr->flags & CHANNEL_HAS_MORE_DATA)) {
+		    !GotFlag(statePtr, CHANNEL_HAS_MORE_DATA)) {
 		/*
 		 * We bypass the driver; it would block as no data is
 		 * available.
@@ -5014,9 +5060,9 @@ Tcl_ReadRaw(
 
 		nread = -1;
 		result = EWOULDBLOCK;
-	    } else {
+	    } else
 #endif /* TCL_IO_TRACK_OS_FOR_DRIVER_WITH_BAD_BLOCKING */
-
+	    {
 		/*
 		 * Now go to the driver to get as much as is possible to fill
 		 * the remaining request. Do all the error handling by
@@ -5026,12 +5072,9 @@ Tcl_ReadRaw(
 		 * The case of 'bytesToRead == 0' at this point cannot happen.
 		 */
 
-		nread = chanPtr->typePtr->inputProc(chanPtr->instanceData,
-			bufPtr + copied, bytesToRead - copied, &result);
-
-#ifdef TCL_IO_TRACK_OS_FOR_DRIVER_WITH_BAD_BLOCKING
+		nread = ChanRead(chanPtr, bufPtr + copied,
+			bytesToRead - copied, &result);
 	    }
-#endif /* TCL_IO_TRACK_OS_FOR_DRIVER_WITH_BAD_BLOCKING */
 
 	    if (nread > 0) {
 		/*
@@ -5055,7 +5098,6 @@ Tcl_ReadRaw(
 		    ResetFlag(statePtr, CHANNEL_HAS_MORE_DATA);
 		}
 #endif /* TCL_IO_TRACK_OS_FOR_DRIVER_WITH_BAD_BLOCKING */
-
 	    } else if (nread == 0) {
 		SetFlag(statePtr, CHANNEL_EOF);
 		statePtr->inputEncodingFlags |= TCL_ENCODING_END;
@@ -5231,9 +5273,8 @@ DoReadChars(
 
 	    bufPtr = statePtr->inQueueHead;
 	    if (IsBufferEmpty(bufPtr)) {
-		ChannelBuffer *nextPtr;
+		ChannelBuffer *nextPtr = bufPtr->nextPtr;
 
-		nextPtr = bufPtr->nextPtr;
 		RecycleBuffer(statePtr, bufPtr, 0);
 		statePtr->inQueueHead = nextPtr;
 		if (nextPtr == NULL) {
@@ -5243,11 +5284,11 @@ DoReadChars(
 	}
 
 	if (copiedNow < 0) {
-	    if (statePtr->flags & CHANNEL_EOF) {
+	    if (GotFlag(statePtr, CHANNEL_EOF)) {
 		break;
 	    }
-	    if (statePtr->flags & CHANNEL_BLOCKED) {
-		if (statePtr->flags & CHANNEL_NONBLOCKING) {
+	    if (GotFlag(statePtr, CHANNEL_BLOCKED)) {
+		if (GotFlag(statePtr, CHANNEL_NONBLOCKING)) {
 		    break;
 		}
 		ResetFlag(statePtr, CHANNEL_BLOCKED);
@@ -5359,7 +5400,7 @@ ReadBytes(
     }
     dst += offset;
 
-    if (statePtr->flags & INPUT_NEED_NL) {
+    if (GotFlag(statePtr, INPUT_NEED_NL)) {
 	ResetFlag(statePtr, INPUT_NEED_NL);
 	if ((srcLen == 0) || (*src != '\n')) {
 	    *dst = '\r';
@@ -5449,7 +5490,7 @@ ReadChars(
     srcLen = BytesLeft(bufPtr);
 
     toRead = charsToRead;
-    if ((unsigned)toRead > (unsigned)srcLen) {
+    if ((unsigned) toRead > (unsigned) srcLen) {
 	toRead = srcLen;
     }
 
@@ -5534,7 +5575,7 @@ ReadChars(
     }
 
     oldState = statePtr->inputEncodingState;
-    if (statePtr->flags & INPUT_NEED_NL) {
+    if (GotFlag(statePtr, INPUT_NEED_NL)) {
 	/*
 	 * We want a '\n' because the last character we saw was '\r'.
 	 */
@@ -5650,16 +5691,15 @@ ReadChars(
      * '\n' in dst.
      */
 
-    numChars -= (dstRead - dstWrote);
+    numChars -= dstRead - dstWrote;
 
     if ((unsigned) numChars > (unsigned) toRead) {
 	/*
 	 * Got too many chars.
 	 */
 
-	const char *eof;
+	const char *eof = Tcl_UtfAtIndex(dst, toRead);
 
-	eof = Tcl_UtfAtIndex(dst, toRead);
 	statePtr->inputEncodingState = oldState;
 	Tcl_ExternalToUtf(NULL, statePtr->encoding, src, srcLen,
 		statePtr->inputEncodingFlags, &statePtr->inputEncodingState,
@@ -5727,9 +5767,8 @@ TranslateInputEOL(
 	 * buffer.
 	 */
 
-	const char *src, *srcMax;
+	const char *src, *srcMax = srcStart + *srcLenPtr;
 
-	srcMax = srcStart + *srcLenPtr;
 	for (src = srcStart; src < srcMax; src++) {
 	    if (*src == inEofChar) {
 		eof = src;
@@ -5800,7 +5839,7 @@ TranslateInputEOL(
 	srcEnd = srcStart + dstLen;
 	srcMax = srcStart + *srcLenPtr;
 
-	if ((statePtr->flags & INPUT_SAW_CR) && (src < srcMax)) {
+	if (GotFlag(statePtr, INPUT_SAW_CR) && (src < srcMax)) {
 	    if (*src == '\n') {
 		src++;
 	    }
@@ -5905,7 +5944,7 @@ Tcl_Ungets(
      * bit. We want to discover these conditions anew in each operation.
      */
 
-    if (statePtr->flags & CHANNEL_STICKY_EOF) {
+    if (GotFlag(statePtr, CHANNEL_STICKY_EOF)) {
 	goto done;
     }
     ResetFlag(statePtr, CHANNEL_BLOCKED | CHANNEL_EOF);
@@ -6162,7 +6201,7 @@ GetInput(
      * platforms it is impossible to read from a device after EOF.
      */
 
-    if (statePtr->flags & CHANNEL_EOF) {
+    if (GotFlag(statePtr, CHANNEL_EOF)) {
 	return 0;
     }
 
@@ -6174,24 +6213,20 @@ GetInput(
      * sure to have data.
      */
 
-    if ((statePtr->flags & CHANNEL_NONBLOCKING) &&
+    if (GotFlag(statePtr, CHANNEL_NONBLOCKING) &&
 	    (Tcl_ChannelBlockModeProc(chanPtr->typePtr) == NULL) &&
-	    !(statePtr->flags & CHANNEL_HAS_MORE_DATA)) {
+	    !GotFlag(statePtr, CHANNEL_HAS_MORE_DATA)) {
 	/*
 	 * Bypass the driver, it would block, as no data is available
 	 */
 
 	nread = -1;
 	result = EWOULDBLOCK;
-    } else {
+    } else
 #endif /* TCL_IO_TRACK_OS_FOR_DRIVER_WITH_BAD_BLOCKING */
-
-	nread = chanPtr->typePtr->inputProc(chanPtr->instanceData,
-		InsertPoint(bufPtr), toRead, &result);
-
-#ifdef TCL_IO_TRACK_OS_FOR_DRIVER_WITH_BAD_BLOCKING
+    {
+	nread = ChanRead(chanPtr, InsertPoint(bufPtr), toRead, &result);
     }
-#endif /* TCL_IO_TRACK_OS_FOR_DRIVER_WITH_BAD_BLOCKING */
 
     if (nread > 0) {
 	bufPtr->nextAdded += nread;
@@ -6217,7 +6252,6 @@ GetInput(
 	    ResetFlag(statePtr, CHANNEL_HAS_MORE_DATA);
 	}
 #endif /* TCL_IO_TRACK_OS_FOR_DRIVER_WITH_BAD_BLOCKING */
-
     } else if (nread == 0) {
 	SetFlag(statePtr, CHANNEL_EOF);
 	statePtr->inputEncodingFlags |= TCL_ENCODING_END;
@@ -6333,8 +6367,8 @@ Tcl_Seek(
      * point. Also clear CR related flags.
      */
 
-    statePtr->flags &=
-	~(CHANNEL_EOF | CHANNEL_STICKY_EOF | CHANNEL_BLOCKED | INPUT_SAW_CR);
+    ResetFlag(statePtr, CHANNEL_EOF | CHANNEL_STICKY_EOF | CHANNEL_BLOCKED |
+	    INPUT_SAW_CR);
 
     /*
      * If the channel is in asynchronous output mode, switch it back to
@@ -6344,14 +6378,14 @@ Tcl_Seek(
      */
 
     wasAsync = 0;
-    if (statePtr->flags & CHANNEL_NONBLOCKING) {
+    if (GotFlag(statePtr, CHANNEL_NONBLOCKING)) {
 	wasAsync = 1;
 	result = StackSetBlockMode(chanPtr, TCL_MODE_BLOCKING);
 	if (result != 0) {
 	    return Tcl_LongAsWide(-1);
 	}
 	ResetFlag(statePtr, CHANNEL_NONBLOCKING);
-	if (statePtr->flags & BG_FLUSH_SCHEDULED) {
+	if (GotFlag(statePtr, BG_FLUSH_SCHEDULED)) {
 	    ResetFlag(statePtr, BG_FLUSH_SCHEDULED);
 	}
     }
@@ -6378,23 +6412,10 @@ Tcl_Seek(
     } else {
 	/*
 	 * Now seek to the new position in the channel as requested by the
-	 * caller. Note that we prefer the wideSeekProc if that is available
-	 * and non-NULL...
+	 * caller.
 	 */
 
-	if (HaveVersion(chanPtr->typePtr, TCL_CHANNEL_VERSION_3) &&
-		chanPtr->typePtr->wideSeekProc != NULL) {
-	    curPos = chanPtr->typePtr->wideSeekProc(chanPtr->instanceData,
-		    offset, mode, &result);
-	} else if (offset < Tcl_LongAsWide(LONG_MIN) ||
-		offset > Tcl_LongAsWide(LONG_MAX)) {
-	    result = EOVERFLOW;
-	    curPos = Tcl_LongAsWide(-1);
-	} else {
-	    curPos = Tcl_LongAsWide(chanPtr->typePtr->seekProc(
-		    chanPtr->instanceData, Tcl_WideAsLong(offset), mode,
-		    &result));
-	}
+	curPos = ChanSeek(chanPtr, offset, mode, &result);
 	if (curPos == Tcl_LongAsWide(-1)) {
 	    Tcl_SetErrno(result);
 	}
@@ -6500,14 +6521,7 @@ Tcl_Tell(
      * wideSeekProc if that is available and non-NULL...
      */
 
-    if (HaveVersion(chanPtr->typePtr, TCL_CHANNEL_VERSION_3) &&
-	    chanPtr->typePtr->wideSeekProc != NULL) {
-	curPos = chanPtr->typePtr->wideSeekProc(chanPtr->instanceData,
-		Tcl_LongAsWide(0), SEEK_CUR, &result);
-    } else {
-	curPos = Tcl_LongAsWide(chanPtr->typePtr->seekProc(
-		chanPtr->instanceData, 0, SEEK_CUR, &result));
-    }
+    curPos = ChanSeek(chanPtr, Tcl_LongAsWide(0), SEEK_CUR, &result);
     if (curPos == Tcl_LongAsWide(-1)) {
 	Tcl_SetErrno(result);
 	return Tcl_LongAsWide(-1);
@@ -6545,19 +6559,18 @@ Tcl_SeekOld(
 {
     Tcl_WideInt wOffset, wResult;
 
-    wOffset = Tcl_LongAsWide((long)offset);
+    wOffset = Tcl_LongAsWide((long) offset);
     wResult = Tcl_Seek(chan, wOffset, mode);
-    return (int)Tcl_WideAsLong(wResult);
+    return (int) Tcl_WideAsLong(wResult);
 }
 
 int
 Tcl_TellOld(
     Tcl_Channel chan)		/* The channel to return pos for. */
 {
-    Tcl_WideInt wResult;
+    Tcl_WideInt wResult = Tcl_Tell(chan);
 
-    wResult = Tcl_Tell(chan);
-    return (int)Tcl_WideAsLong(wResult);
+    return (int) Tcl_WideAsLong(wResult);
 }
 
 /*
@@ -6598,7 +6611,7 @@ Tcl_TruncateChannel(
 	return TCL_ERROR;
     }
 
-    if (!(chanPtr->state->flags & TCL_WRITABLE)) {
+    if (!GotFlag(chanPtr->state, TCL_WRITABLE)) {
 	/*
 	 * We require that the file was opened of writing. Do that check now
 	 * so that we only flush if we think we're going to succeed.
@@ -6613,7 +6626,7 @@ Tcl_TruncateChannel(
      * pre-read input data.
      */
 
-    if (Tcl_Seek(chan, (Tcl_WideInt)0, SEEK_CUR) == Tcl_LongAsWide(-1)) {
+    if (Tcl_Seek(chan, (Tcl_WideInt) 0, SEEK_CUR) == Tcl_LongAsWide(-1)) {
 	return TCL_ERROR;
     }
 
@@ -6684,8 +6697,7 @@ CheckChannelErrors(
      * order to drain data from stacked channels.
      */
 
-    if ((statePtr->flags & CHANNEL_CLOSED) &&
-	    ((flags & CHANNEL_RAW_MODE) == 0)) {
+    if (GotFlag(statePtr, CHANNEL_CLOSED) && !(flags & CHANNEL_RAW_MODE)) {
 	Tcl_SetErrno(EACCES);
 	return -1;
     }
@@ -6720,7 +6732,7 @@ CheckChannelErrors(
 	 * discover these conditions anew in each operation.
 	 */
 
-	if ((statePtr->flags & CHANNEL_STICKY_EOF) == 0) {
+	if (!GotFlag(statePtr, CHANNEL_STICKY_EOF)) {
 	    ResetFlag(statePtr, CHANNEL_EOF);
 	}
 	ResetFlag(statePtr, CHANNEL_BLOCKED | CHANNEL_NEED_MORE_DATA);
@@ -6752,8 +6764,8 @@ Tcl_Eof(
     ChannelState *statePtr = ((Channel *) chan)->state;
 				/* State of real channel structure. */
 
-    return ((statePtr->flags & CHANNEL_STICKY_EOF) ||
-	    ((statePtr->flags & CHANNEL_EOF) &&
+    return (GotFlag(statePtr, CHANNEL_STICKY_EOF) ||
+	    (GotFlag(statePtr, CHANNEL_EOF) &&
 	    (Tcl_InputBuffered(chan) == 0))) ? 1 : 0;
 }
 
@@ -6780,7 +6792,7 @@ Tcl_InputBlocked(
     ChannelState *statePtr = ((Channel *) chan)->state;
 				/* State of real channel structure. */
 
-    return (statePtr->flags & CHANNEL_BLOCKED) ? 1 : 0;
+    return GotFlag(statePtr, CHANNEL_BLOCKED) ? 1 : 0;
 }
 
 /*
@@ -6933,9 +6945,9 @@ Tcl_SetChannelBufferSize(
      */
 
     if (sz < 1) {
-      sz = 1;
+	sz = 1;
     } else if (sz > MAX_CHANNEL_BUFFER_SIZE) {
-      sz = MAX_CHANNEL_BUFFER_SIZE;
+	sz = MAX_CHANNEL_BUFFER_SIZE;
     }
 
     statePtr = ((Channel *) chan)->state;
@@ -6945,9 +6957,8 @@ Tcl_SetChannelBufferSize(
 	ckfree((char *) statePtr->outputStage);
 	statePtr->outputStage = NULL;
     }
-    if ((statePtr->encoding != NULL) && (statePtr->flags & TCL_WRITABLE)) {
-	statePtr->outputStage = (char *)
-		ckalloc((unsigned) (statePtr->bufSize + 2));
+    if ((statePtr->encoding != NULL) && GotFlag(statePtr, TCL_WRITABLE)) {
+	statePtr->outputStage = ckalloc((unsigned) statePtr->bufSize + 2);
     }
 }
 
@@ -7103,9 +7114,9 @@ Tcl_GetChannelOption(
      */
 
     if (statePtr->csPtrR) {
-      flags = statePtr->csPtrR->readFlags;
+	flags = statePtr->csPtrR->readFlags;
     } else if (statePtr->csPtrW) {
-      flags = statePtr->csPtrW->writeFlags;
+	flags = statePtr->csPtrW->writeFlags;
     } else {
 	flags = statePtr->flags;
     }
@@ -7357,8 +7368,7 @@ Tcl_SetChannelOption(
     } else if (HaveOpt(7, "-buffering")) {
 	len = strlen(newValue);
 	if ((newValue[0] == 'f') && (strncmp(newValue, "full", len) == 0)) {
-	    statePtr->flags &=
-		    ~(CHANNEL_UNBUFFERED|CHANNEL_LINEBUFFERED);
+	    ResetFlag(statePtr, CHANNEL_UNBUFFERED | CHANNEL_LINEBUFFERED);
 	} else if ((newValue[0] == 'l') &&
 		(strncmp(newValue, "line", len) == 0)) {
 	    ResetFlag(statePtr, CHANNEL_UNBUFFERED);
@@ -7423,6 +7433,7 @@ Tcl_SetChannelOption(
 	    int outIndex = (argc - 1);
 	    int inValue = (int) argv[0][0];
 	    int outValue = (int) argv[outIndex][0];
+
 	    if (inValue & 0x80 || outValue & 0x80) {
 		if (interp) {
 		    Tcl_AppendResult(interp, "bad value for -eofchar: ",
@@ -7431,10 +7442,10 @@ Tcl_SetChannelOption(
 		ckfree((char *) argv);
 		return TCL_ERROR;
 	    }
-	    if (statePtr->flags & TCL_READABLE) {
+	    if (GotFlag(statePtr, TCL_READABLE)) {
 		statePtr->inEofChar = inValue;
 	    }
-	    if (statePtr->flags & TCL_WRITABLE) {
+	    if (GotFlag(statePtr, TCL_WRITABLE)) {
 		statePtr->outEofChar = outValue;
 	    }
 	} else {
@@ -7456,9 +7467,7 @@ Tcl_SetChannelOption(
 	 * ahead'. Ditto for blocked.
 	 */
 
-	statePtr->flags &=
-		~(CHANNEL_EOF | CHANNEL_STICKY_EOF | CHANNEL_BLOCKED);
-
+	ResetFlag(statePtr, CHANNEL_EOF|CHANNEL_STICKY_EOF|CHANNEL_BLOCKED);
 	return TCL_OK;
     } else if (HaveOpt(1, "-translation")) {
 	const char *readMode, *writeMode;
@@ -7468,11 +7477,11 @@ Tcl_SetChannelOption(
 	}
 
 	if (argc == 1) {
-	    readMode = (statePtr->flags & TCL_READABLE) ? argv[0] : NULL;
-	    writeMode = (statePtr->flags & TCL_WRITABLE) ? argv[0] : NULL;
+	    readMode = GotFlag(statePtr, TCL_READABLE) ? argv[0] : NULL;
+	    writeMode = GotFlag(statePtr, TCL_WRITABLE) ? argv[0] : NULL;
 	} else if (argc == 2) {
-	    readMode = (statePtr->flags & TCL_READABLE) ? argv[0] : NULL;
-	    writeMode = (statePtr->flags & TCL_WRITABLE) ? argv[1] : NULL;
+	    readMode = GotFlag(statePtr, TCL_READABLE) ? argv[0] : NULL;
+	    writeMode = GotFlag(statePtr, TCL_WRITABLE) ? argv[1] : NULL;
 	} else {
 	    if (interp) {
 		Tcl_AppendResult(interp,
@@ -7485,6 +7494,7 @@ Tcl_SetChannelOption(
 
 	if (readMode) {
 	    TclEolTranslation translation;
+
 	    if (*readMode == '\0') {
 		translation = statePtr->inputTranslation;
 	    } else if (strcmp(readMode, "auto") == 0) {
@@ -7597,7 +7607,7 @@ Tcl_SetChannelOption(
 	ckfree(statePtr->outputStage);
 	statePtr->outputStage = NULL;
     }
-    if ((statePtr->encoding != NULL) && (statePtr->flags & TCL_WRITABLE)) {
+    if ((statePtr->encoding != NULL) && GotFlag(statePtr, TCL_WRITABLE)) {
 	statePtr->outputStage = ckalloc((unsigned) (statePtr->bufSize + 2));
     }
     return TCL_OK;
@@ -7699,9 +7709,9 @@ Tcl_NotifyChannel(
      */
 
     if ((mask & TCL_READABLE) &&
-	    (statePtr->flags & CHANNEL_NONBLOCKING) &&
+	    GotFlag(statePtr, CHANNEL_NONBLOCKING) &&
 	    (Tcl_ChannelBlockModeProc(chanPtr->typePtr) == NULL) &&
-	    !(statePtr->flags & CHANNEL_TIMER_FEV)) {
+	    !GotFlag(statePtr, CHANNEL_TIMER_FEV)) {
 	SetFlag(statePtr, CHANNEL_HAS_MORE_DATA);
     }
 #endif /* TCL_IO_TRACK_OS_FOR_DRIVER_WITH_BAD_BLOCKING */
@@ -7718,7 +7728,7 @@ Tcl_NotifyChannel(
      * their own events and pass them upward.
      */
 
-    while (mask && (chanPtr->upChanPtr != (NULL))) {
+    while (mask && (chanPtr->upChanPtr != NULL)) {
 	Tcl_DriverHandlerProc *upHandlerProc;
 
 	upChanPtr = chanPtr->upChanPtr;
@@ -7764,7 +7774,7 @@ Tcl_NotifyChannel(
      * don't call any write handlers before the flush is complete.
      */
 
-    if ((statePtr->flags & BG_FLUSH_SCHEDULED) && (mask & TCL_WRITABLE)) {
+    if (GotFlag(statePtr, BG_FLUSH_SCHEDULED) && (mask & TCL_WRITABLE)) {
 	FlushChannel(NULL, chanPtr, 1);
 	mask &= ~TCL_WRITABLE;
     }
@@ -7839,7 +7849,7 @@ UpdateInterest(
      * watch for the channel to become writable.
      */
 
-    if (statePtr->flags & BG_FLUSH_SCHEDULED) {
+    if (GotFlag(statePtr, BG_FLUSH_SCHEDULED)) {
 	mask |= TCL_WRITABLE;
     }
 
@@ -7851,7 +7861,7 @@ UpdateInterest(
      */
 
     if (mask & TCL_READABLE) {
-	if (!(statePtr->flags & CHANNEL_NEED_MORE_DATA)
+	if (!GotFlag(statePtr, CHANNEL_NEED_MORE_DATA)
 		&& (statePtr->inQueueHead != NULL)
 		&& IsBufferReady(statePtr->inQueueHead)) {
 	    mask &= ~TCL_READABLE;
@@ -7902,7 +7912,7 @@ UpdateInterest(
 	    }
 	}
     }
-    chanPtr->typePtr->watchProc(chanPtr->instanceData, mask);
+    ChanWatch(chanPtr, mask);
 }
 
 /*
@@ -7930,7 +7940,7 @@ ChannelTimerProc(
     ChannelState *statePtr = chanPtr->state;
 				/* State info for channel */
 
-    if (!(statePtr->flags & CHANNEL_NEED_MORE_DATA)
+    if (!GotFlag(statePtr, CHANNEL_NEED_MORE_DATA)
 	    && (statePtr->interestMask & TCL_READABLE)
 	    && (statePtr->inQueueHead != NULL)
 	    && IsBufferReady(statePtr->inQueueHead)) {
@@ -7950,8 +7960,8 @@ ChannelTimerProc(
 	 * similar test is done in "PeekAhead".
 	 */
 
-	if ((statePtr->flags & CHANNEL_NONBLOCKING) &&
-	    (Tcl_ChannelBlockModeProc(chanPtr->typePtr) == NULL)) {
+	if (GotFlag(statePtr, CHANNEL_NONBLOCKING) &&
+		(Tcl_ChannelBlockModeProc(chanPtr->typePtr) == NULL)) {
 	    SetFlag(statePtr, CHANNEL_TIMER_FEV);
 	}
 #endif /* TCL_IO_TRACK_OS_FOR_DRIVER_WITH_BAD_BLOCKING */
@@ -8368,6 +8378,7 @@ Tcl_FileEventObjCmd(
 
     if (objc == 3) {
 	EventScriptRecord *esPtr;
+
 	for (esPtr = statePtr->scriptRecordPtr; esPtr != NULL;
 		esPtr = esPtr->nextPtr) {
 	    if ((esPtr->interp == interp) && (esPtr->mask == mask)) {
@@ -8480,8 +8491,8 @@ TclCopyChannel(
      * Make sure the output side is unbuffered.
      */
 
-    outStatePtr->flags = (outStatePtr->flags & ~(CHANNEL_LINEBUFFERED))
-	| CHANNEL_UNBUFFERED;
+    outStatePtr->flags = (outStatePtr->flags & ~CHANNEL_LINEBUFFERED)
+	    | CHANNEL_UNBUFFERED;
 
     /*
      * Allocate a new CopyState to maintain info about the current copy in
@@ -8593,7 +8604,7 @@ CopyData(
 	     * underflow instead to prime the readable fileevent.
 	     */
 
-	    size      = 0;
+	    size = 0;
 	    underflow = 1;
 	} else {
 	    /*
@@ -8732,7 +8743,7 @@ CopyData(
 	 * therefore we don't need a writable handler.
 	 */
 
-	if (!underflow && (outStatePtr->flags & BG_FLUSH_SCHEDULED)) {
+	if (!underflow && GotFlag(outStatePtr, BG_FLUSH_SCHEDULED)) {
 	    if (!(mask & TCL_WRITABLE)) {
 		if (mask & TCL_READABLE) {
 		    Tcl_DeleteChannelHandler(inChan, CopyEventProc, csPtr);
@@ -8783,6 +8794,7 @@ CopyData(
     total = csPtr->total;
     if (cmdPtr && interp) {
 	int code;
+
 	/*
 	 * Get a private copy of the command so we can mutate it by adding
 	 * arguments. Note that StopCopy frees our saved reference to the
@@ -8859,7 +8871,7 @@ DoRead(
      * operation.
      */
 
-    if (!(statePtr->flags & CHANNEL_STICKY_EOF)) {
+    if (!GotFlag(statePtr, CHANNEL_STICKY_EOF)) {
 	ResetFlag(statePtr, CHANNEL_EOF);
     }
     ResetFlag(statePtr, CHANNEL_BLOCKED | CHANNEL_NEED_MORE_DATA);
@@ -8868,11 +8880,11 @@ DoRead(
 	copiedNow = CopyAndTranslateBuffer(statePtr, bufPtr + copied,
 		toRead - copied);
 	if (copiedNow == 0) {
-	    if (statePtr->flags & CHANNEL_EOF) {
+	    if (GotFlag(statePtr, CHANNEL_EOF)) {
 		goto done;
 	    }
-	    if (statePtr->flags & CHANNEL_BLOCKED) {
-		if (statePtr->flags & CHANNEL_NONBLOCKING) {
+	    if (GotFlag(statePtr, CHANNEL_BLOCKED)) {
+		if (GotFlag(statePtr, CHANNEL_NONBLOCKING)) {
 		    goto done;
 		}
 		ResetFlag(statePtr, CHANNEL_BLOCKED);
@@ -9026,7 +9038,7 @@ CopyAndTranslateBuffer(
 	    curByte = *src;
 	    if (curByte == '\n') {
 		ResetFlag(statePtr, INPUT_SAW_CR);
-	    } else if (statePtr->flags & INPUT_SAW_CR) {
+	    } else if (GotFlag(statePtr, INPUT_SAW_CR)) {
 		ResetFlag(statePtr, INPUT_SAW_CR);
 		*dst = '\r';
 		dst++;
@@ -9069,7 +9081,7 @@ CopyAndTranslateBuffer(
 		*dst = '\n';
 		dst++;
 	    } else {
-		if ((curByte != '\n') || !(statePtr->flags & INPUT_SAW_CR)) {
+		if ((curByte != '\n') || !GotFlag(statePtr, INPUT_SAW_CR)) {
 		    *dst = (char) curByte;
 		    dst++;
 		}
@@ -9338,10 +9350,10 @@ DoWrite(
 	 */
 
 	outBufPtr->nextAdded += destCopied;
-	if (!(statePtr->flags & BUFFER_READY)) {
+	if (!GotFlag(statePtr, BUFFER_READY)) {
 	    if (IsBufferFull(outBufPtr)) {
 		SetFlag(statePtr, BUFFER_READY);
-	    } else if (statePtr->flags & CHANNEL_LINEBUFFERED) {
+	    } else if (GotFlag(statePtr, CHANNEL_LINEBUFFERED)) {
 		for (sPtr = src, i = 0, foundNewline = 0;
 			(i < srcCopied) && (!foundNewline);
 			i++, sPtr++) {
@@ -9353,7 +9365,7 @@ DoWrite(
 		if (foundNewline) {
 		    SetFlag(statePtr, BUFFER_READY);
 		}
-	    } else if (statePtr->flags & CHANNEL_UNBUFFERED) {
+	    } else if (GotFlag(statePtr, CHANNEL_UNBUFFERED)) {
 		SetFlag(statePtr, BUFFER_READY);
 	    }
 	}
@@ -9362,7 +9374,7 @@ DoWrite(
 	src += srcCopied;
 	srcLen -= srcCopied;
 
-	if (statePtr->flags & BUFFER_READY) {
+	if (GotFlag(statePtr, BUFFER_READY)) {
 	    if (FlushChannel(NULL, chanPtr, 0) != 0) {
 		return -1;
 	    }
@@ -9433,19 +9445,19 @@ StopCopy(
      * Restore the old blocking mode and output buffering mode.
      */
 
-    nonBlocking = (csPtr->readFlags & CHANNEL_NONBLOCKING);
+    nonBlocking = csPtr->readFlags & CHANNEL_NONBLOCKING;
     if (nonBlocking != (inStatePtr->flags & CHANNEL_NONBLOCKING)) {
 	SetBlockMode(NULL, csPtr->readPtr,
 		nonBlocking ? TCL_MODE_NONBLOCKING : TCL_MODE_BLOCKING);
     }
     if (csPtr->readPtr != csPtr->writePtr) {
-	nonBlocking = (csPtr->writeFlags & CHANNEL_NONBLOCKING);
+	nonBlocking = csPtr->writeFlags & CHANNEL_NONBLOCKING;
 	if (nonBlocking != (outStatePtr->flags & CHANNEL_NONBLOCKING)) {
 	    SetBlockMode(NULL, csPtr->writePtr,
 		    nonBlocking ? TCL_MODE_NONBLOCKING : TCL_MODE_BLOCKING);
 	}
     }
-    outStatePtr->flags &= ~(CHANNEL_LINEBUFFERED | CHANNEL_UNBUFFERED);
+    ResetFlag(outStatePtr, CHANNEL_LINEBUFFERED | CHANNEL_UNBUFFERED);
     outStatePtr->flags |=
 	    csPtr->writeFlags & (CHANNEL_LINEBUFFERED | CHANNEL_UNBUFFERED);
 
@@ -10635,8 +10647,9 @@ SetChannelFromAny(
 	 * The channel is valid until any call to DetachChannel occurs.
 	 * Ensure consistency checks are done.
 	 */
+
 	statePtr = GET_CHANNELSTATE(objPtr);
-	if (statePtr->flags & (CHANNEL_TAINTED|CHANNEL_CLOSED)) {
+	if (GotFlag(statePtr, CHANNEL_TAINTED|CHANNEL_CLOSED)) {
 	    ResetFlag(statePtr, CHANNEL_TAINTED);
 	    Tcl_Release(statePtr);
 	    UpdateStringOfChannel(objPtr);
@@ -10650,6 +10663,7 @@ SetChannelFromAny(
 	 * We need a valid string with which to check for a valid channel, but
 	 * make sure not to free internal rep until validated. [Bug 1847044]
 	 */
+
 	if ((objPtr->typePtr != NULL) && (objPtr->bytes == NULL)) {
 	    objPtr->typePtr->updateStringProc(objPtr);
 	}
@@ -10693,8 +10707,10 @@ UpdateStringOfChannel(
     if (objPtr->bytes == NULL) {
 	ChannelState *statePtr = GET_CHANNELSTATE(objPtr);
 	const char *name = statePtr->channelName;
+
 	if (name) {
 	    size_t len = strlen(name);
+
 	    objPtr->bytes = (char *) ckalloc(len + 1);
 	    objPtr->length = len;
 	    memcpy(objPtr->bytes, name, len);