protect Tcl_WinUtfToTChar/Tcl_WinTCharToUtf against NULL input values: return empty string in that case.

Add TIP #494-compatible definitions of TCL_IO_FAILURE/TCL_AUTO_LENGTH, and use it in some appropriate places.

6 files changed, 26 insertions, 13 deletions

diff --git a/generic/tcl.h b/generic/tcl.h
index 2ced16b..0971066 100644
--- a/generic/tcl.h
+++ b/generic/tcl.h
@@ -224,7 +224,7 @@ extern "C" {
  * to be included in a shared library, then it should have the DLLEXPORT
  * storage class. If is being declared for use by a module that is going to
  * link against the shared library, then it should have the DLLIMPORT storage
- * class. If the symbol is beind declared for a static build or for use from a
+ * class. If the symbol is being declared for a static build or for use from a
  * stub library, then the storage class should be empty.
  *
  * The convention is that a macro called BUILD_xxxx, where xxxx is the name of
@@ -2334,6 +2334,13 @@ typedef int (Tcl_ArgvGenFuncProc)(ClientData clientData, Tcl_Interp *interp,
 #define TCL_TCPSERVER_REUSEPORT (1<<1)
 
 /*
+ * Constants for special int-typed values, see TIP #494
+ */
+
+#define TCL_IO_FAILURE	(-1)
+#define TCL_AUTO_LENGTH	(-1)
+
+/*
  *----------------------------------------------------------------------------
  * Single public declaration for NRE.
  */
diff --git a/generic/tclIOCmd.c b/generic/tclIOCmd.c
index d38240a..1dd8666 100644
--- a/generic/tclIOCmd.c
+++ b/generic/tclIOCmd.c
@@ -991,7 +991,7 @@ Tcl_ExecObjCmd(
 
     resultPtr = Tcl_NewObj();
     if (Tcl_GetChannelHandle(chan, TCL_READABLE, NULL) == TCL_OK) {
-	if (Tcl_ReadChars(chan, resultPtr, -1, 0) < 0) {
+	if (Tcl_ReadChars(chan, resultPtr, -1, 0) == TCL_IO_FAILURE) {
 	    /*
 	     * TIP #219.
 	     * Capture error messages put by the driver into the bypass area
diff --git a/generic/tclIOUtil.c b/generic/tclIOUtil.c
index 11cc22d..63d16be 100644
--- a/generic/tclIOUtil.c
+++ b/generic/tclIOUtil.c
@@ -1807,7 +1807,7 @@ Tcl_FSEvalFileEx(
      * be handled especially.
      */
 
-    if (Tcl_ReadChars(chan, objPtr, 1, 0) < 0) {
+    if (Tcl_ReadChars(chan, objPtr, 1, 0) == TCL_IO_FAILURE) {
 	Tcl_Close(interp, chan);
 	Tcl_SetObjResult(interp, Tcl_ObjPrintf(
 		"couldn't read file \"%s\": %s",
@@ -1822,7 +1822,7 @@ Tcl_FSEvalFileEx(
      */
 
     if (Tcl_ReadChars(chan, objPtr, -1,
-	    memcmp(string, "\xef\xbb\xbf", 3)) < 0) {
+	    memcmp(string, "\xef\xbb\xbf", 3)) == TCL_IO_FAILURE) {
 	Tcl_Close(interp, chan);
 	Tcl_SetObjResult(interp, Tcl_ObjPrintf(
 		"couldn't read file \"%s\": %s",
@@ -1942,7 +1942,7 @@ TclNREvalFile(
      * be handled especially.
      */
 
-    if (Tcl_ReadChars(chan, objPtr, 1, 0) < 0) {
+    if (Tcl_ReadChars(chan, objPtr, 1, 0) == TCL_IO_FAILURE) {
 	Tcl_Close(interp, chan);
 	Tcl_SetObjResult(interp, Tcl_ObjPrintf(
 		"couldn't read file \"%s\": %s",
@@ -1958,7 +1958,7 @@ TclNREvalFile(
      */
 
     if (Tcl_ReadChars(chan, objPtr, -1,
-	    memcmp(string, "\xef\xbb\xbf", 3)) < 0) {
+	    memcmp(string, "\xef\xbb\xbf", 3)) == TCL_IO_FAILURE) {
 	Tcl_Close(interp, chan);
 	Tcl_SetObjResult(interp, Tcl_ObjPrintf(
 		"couldn't read file \"%s\": %s",
diff --git a/generic/tclZipfs.c b/generic/tclZipfs.c
index b609779..5342fb1 100644
--- a/generic/tclZipfs.c
+++ b/generic/tclZipfs.c
@@ -4726,9 +4726,6 @@ TclZipfs_AppHook(
 #endif /* _WIN32 */
     ***argvPtr)			/* Pointer to argv */
 {
-#ifdef _WIN32
-    Tcl_DString ds;
-#endif /* _WIN32 */
     char *archive;
 
     Tcl_FindExecutable((*argvPtr)[0]);
@@ -4773,6 +4770,9 @@ TclZipfs_AppHook(
 	}
 #ifdef SUPPORT_BUILTIN_ZIP_INSTALL
     } else if (*argcPtr > 1) {
+#ifdef _WIN32
+	Tcl_DString ds;
+#endif /* _WIN32 */
 	/*
 	 * If the first argument is "install", run the supplied installer
 	 * script.
diff --git a/generic/tclZlib.c b/generic/tclZlib.c
index 644ac8b..9bad36d 100644
--- a/generic/tclZlib.c
+++ b/generic/tclZlib.c
@@ -2931,7 +2931,7 @@ ZlibTransformClose(
 		result = TCL_ERROR;
 		break;
 	    }
-	    if (written && Tcl_WriteRaw(cd->parent, cd->outBuffer, written) < 0) {
+	    if (written && Tcl_WriteRaw(cd->parent, cd->outBuffer, written) == TCL_IO_FAILURE) {
 		/* TODO: is this the right way to do errors on close?
 		 * Note: when close is called from FinalizeIOSubsystem then
 		 * interp may be NULL */
@@ -3130,7 +3130,7 @@ ZlibTransformOutput(
 	    break;
 	}
 
-	if (Tcl_WriteRaw(cd->parent, cd->outBuffer, produced) < 0) {
+	if (Tcl_WriteRaw(cd->parent, cd->outBuffer, produced) == TCL_IO_FAILURE) {
 	    *errorCodePtr = Tcl_GetErrno();
 	    return -1;
 	}
@@ -3186,7 +3186,7 @@ ZlibTransformFlush(
 	 * Write the bytes we've received to the next layer.
 	 */
 
-	if (len > 0 && Tcl_WriteRaw(cd->parent, cd->outBuffer, len) < 0) {
+	if (len > 0 && Tcl_WriteRaw(cd->parent, cd->outBuffer, len) == TCL_IO_FAILURE) {
 	    Tcl_SetObjResult(interp, Tcl_ObjPrintf(
 		    "problem flushing channel: %s",
 		    Tcl_PosixError(interp)));
diff --git a/win/tclWin32Dll.c b/win/tclWin32Dll.c
index 1a33514..04d27dd 100644
--- a/win/tclWin32Dll.c
+++ b/win/tclWin32Dll.c
@@ -472,6 +472,9 @@ Tcl_WinUtfToTChar(
 				 * converted string is stored. */
 {
     Tcl_DStringInit(dsPtr);
+    if (!string) {
+	return (TCHAR *)Tcl_DStringValue(dsPtr);
+    }
     return Tcl_UtfToUniCharDString(string, len, dsPtr);
 }
 
@@ -483,12 +486,15 @@ Tcl_WinTCharToUtf(
     Tcl_DString *dsPtr)		/* Uninitialized or free DString in which the
 				 * converted string is stored. */
 {
+    Tcl_DStringInit(dsPtr);
+    if (!string) {
+	return Tcl_DStringValue(dsPtr);
+    }
     if (len > 0) {
 	len /= 2;
     } else if (len < 0) {
 	len = wcslen(string);
     }
-    Tcl_DStringInit(dsPtr);
     return Tcl_UniCharToUtfDString(string, len, dsPtr);
 }