Added code to try to tame the [file attributes] guts, while trying to simplify

things enough that I can puzzle out AK's TclVFS problems. I suspect this is not
a real fix though; just an attempt to make the problem tractable.

2 files changed, 31 insertions, 21 deletions

diff --git a/ChangeLog b/ChangeLog
index 508a72d..1297137 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,9 +1,16 @@
+2011-04-16  Donal K. Fellows  <dkf@users.sf.net>
+
+	* generic/tclFCmd.c (TclFileAttrsCmd): Tidied up the memory management
+	a bit to try to ensure that the dynamic and static cases don't get
+	confused while still promoting caching where possible. Added a panic
+	to trap problems in the case where an extension is misusing the API.
+
 2011-04-13  Don Porter  <dgp@users.sourceforge.net>
 
-	* generic/tclUtil.c:	Rewrite of Tcl_Concat*() routines to 
-	prevent segfaults on buffer overflow.  Build them out of existing
-	primitives already coded to handle overflow properly.  Uses the
-	new TclTrim*() routines. [Bug 3285375]
+	* generic/tclUtil.c:	[Bug 3285375]: Rewrite of Tcl_Concat*()
+	routines to prevent segfaults on buffer overflow.  Build them out of
+	existing primitives already coded to handle overflow properly.  Uses
+	the new TclTrim*() routines.
 
 	* generic/tclCmdMZ.c:	New internal utility routines TclTrimLeft()
 	* generic/tclInt.h:	and TclTrimRight().  Refactor the
@@ -11,14 +18,14 @@
 
 2011-04-13  Miguel Sofer  <msofer@users.sf.net>
 
-	* generic/tclVar.c: fix for [Bug 2662380], crash caused by
-	appending to a variable with a write trace that unsets it.
+	* generic/tclVar.c: [Bug 2662380]: Fix crash caused by appending to a
+	variable with a write trace that unsets it.
 
 2011-04-12  Don Porter  <dgp@users.sourceforge.net>
 
-	* generic/tclStringObj.c:	Repair corruption in [string reverse]
-	* tests/string.test:	when string rep invalidation failed to also
-	reset the bytes allocated for string rep to zero [Bug 3285472].
+	* generic/tclStringObj.c:	[Bug 3285472]: Repair corruption in
+	* tests/string.test:	[string reverse] when string rep invalidation
+	failed to also reset the bytes allocated for string rep to zero.
 
 2011-04-12  Venkat Iyer <venkat@comit.com>
 
@@ -26,7 +33,7 @@
 
 2011-04-06  Miguel Sofer  <msofer@users.sf.net>
 
-	* generic/tclExecute.c (TclCompEvalObj): earlier return if Tip280 
+	* generic/tclExecute.c (TclCompEvalObj): Earlier return if Tip280
 	gymnastics not needed.
 
 2011-04-05  Venkat Iyer <venkat@comit.com>
@@ -47,8 +54,8 @@
 
 2011-04-02  Kevin B. Kenny  <kennykb@acm.org>
 
-	* generic/tclStrToD.c (QuickConversion): Replaced another couple
-	of 'double' declarations with 'volatile double' to work around
+	* generic/tclStrToD.c (QuickConversion): Replaced another couple of
+	'double' declarations with 'volatile double' to work around
 	misrounding issues in mingw-gcc 3.4.5.
 
 2011-03-24  Donal K. Fellows  <dkf@users.sf.net>
diff --git a/generic/tclFCmd.c b/generic/tclFCmd.c
index 53f955f..5850846 100644
--- a/generic/tclFCmd.c
+++ b/generic/tclFCmd.c
@@ -950,7 +950,7 @@ TclFileAttrsCmd(
     int result;
     CONST char ** attributeStrings;
     Tcl_Obj* objStrings = NULL;
-    int numObjStrings = -1;
+    int numObjStrings = -1, didAlloc = 0;
     Tcl_Obj *filePtr;
 
     if (objc < 3) {
@@ -983,9 +983,8 @@ TclFileAttrsCmd(
 		Tcl_AppendResult(interp, "could not read \"",
 			TclGetString(filePtr), "\": ", Tcl_PosixError(interp),
 			NULL);
-		return TCL_ERROR;
 	    }
-	    goto end;
+	    return TCL_ERROR;
 	}
 
 	/*
@@ -1003,12 +1002,16 @@ TclFileAttrsCmd(
 	}
 	attributeStrings = (CONST char **) TclStackAlloc(interp,
 		(1+numObjStrings) * sizeof(char*));
+	didAlloc = 1;
 	for (index = 0; index < numObjStrings; index++) {
 	    Tcl_ListObjIndex(interp, objStrings, index, &objPtr);
 	    attributeStrings[index] = TclGetString(objPtr);
 	}
 	attributeStrings[index] = NULL;
+    } else if (objStrings != NULL) {
+	Tcl_Panic("must not update objPtrRef's variable and return non-NULL");
     }
+
     if (objc == 0) {
 	/*
 	 * Get all attributes.
@@ -1069,7 +1072,7 @@ TclFileAttrsCmd(
 		"option", 0, &index) != TCL_OK) {
 	    goto end;
 	}
-	if (numObjStrings != -1) {
+	if (didAlloc) {
 	    TclFreeIntRep(objv[0]);
 	}
 	if (Tcl_FSFileAttrsGet(interp, index, filePtr,
@@ -1096,7 +1099,7 @@ TclFileAttrsCmd(
 		    "option", 0, &index) != TCL_OK) {
 		goto end;
     	    }
-	    if (numObjStrings != -1) {
+	    if (didAlloc) {
 		TclFreeIntRep(objv[i]);
 	    }
 	    if (i + 1 == objc) {
@@ -1113,20 +1116,20 @@ TclFileAttrsCmd(
     result = TCL_OK;
 
   end:
-    if (numObjStrings != -1) {
+    if (didAlloc) {
 	/*
 	 * Free up the array we allocated.
 	 */
 
 	TclStackFree(interp, (void *)attributeStrings);
+    }
 
+    if (objStrings != NULL) {
 	/*
 	 * We don't need this object that was passed to us any more.
 	 */
 
-	if (objStrings != NULL) {
-	    Tcl_DecrRefCount(objStrings);
-	}
+	Tcl_DecrRefCount(objStrings);
     }
     return result;
 }