Reduce amount of unreachable code. Refactor Win socket and load code to be less

baroque in its internals.

1 files changed, 124 insertions, 105 deletions

diff --git a/win/tclWinLoad.c b/win/tclWinLoad.c
index 3f4d4d9..5848daa 100644
--- a/win/tclWinLoad.c
+++ b/win/tclWinLoad.c
@@ -14,24 +14,22 @@
 #include "tclWinInt.h"
 
 /*
- * Mutex protecting static data in this file;
+ * Native name of the directory in the native filesystem where DLLs used in
+ * this process are copied prior to loading, and mutex used to protect its
+ * allocation.
  */
 
-static Tcl_Mutex loadMutex;
+static WCHAR *dllDirectoryName = NULL;
+static Tcl_Mutex dllDirectoryNameMutex;
 
 /*
- * Name of the directory in the native filesystem where DLLs used in this
- * process are copied prior to loading.
+ * Static functions defined within this file.
  */
 
-static WCHAR* dllDirectoryName = NULL;
-
-/* Static functions defined within this file */
-
-void* FindSymbol(Tcl_Interp* interp, Tcl_LoadHandle loadHandle,
-		 const char* symbol);
-void UnloadFile(Tcl_LoadHandle loadHandle);
-
+static void *		FindSymbol(Tcl_Interp *interp,
+			    Tcl_LoadHandle loadHandle, const char *symbol);
+static void		InitDLLDirectoryName(void);
+static void		UnloadFile(Tcl_LoadHandle loadHandle);
 
 /*
  *----------------------------------------------------------------------
@@ -75,8 +73,7 @@ TclpDlopen(
      */
 
     nativeName = Tcl_FSGetNativePath(pathPtr);
-    hInstance = LoadLibraryEx(nativeName, NULL,
-	    LOAD_WITH_ALTERED_SEARCH_PATH);
+    hInstance = LoadLibraryEx(nativeName,NULL,LOAD_WITH_ALTERED_SEARCH_PATH);
     if (hInstance == NULL) {
 	/*
 	 * Let the OS loader examine the binary search path for whatever
@@ -85,9 +82,8 @@ TclpDlopen(
 	 */
 
 	Tcl_DString ds;
-	const char *fileName = Tcl_GetString(pathPtr);
 
-	nativeName = Tcl_WinUtfToTChar(fileName, -1, &ds);
+	nativeName = Tcl_WinUtfToTChar(Tcl_GetString(pathPtr), -1, &ds);
 	hInstance = LoadLibraryEx(nativeName, NULL,
 		LOAD_WITH_ALTERED_SEARCH_PATH);
 	Tcl_DStringFree(&ds);
@@ -96,23 +92,6 @@ TclpDlopen(
     if (hInstance == NULL) {
 	DWORD lastError = GetLastError();
 
-#if 0
-	/*
-	 * It would be ideal if the FormatMessage stuff worked better, but
-	 * unfortunately it doesn't seem to want to...
-	 */
-
-	LPTSTR lpMsgBuf;
-	char *buf;
-	int size;
-
-	size = FormatMessage(FORMAT_MESSAGE_FROM_SYSTEM |
-		FORMAT_MESSAGE_ALLOCATE_BUFFER, NULL, lastError, 0,
-		(LPTSTR) &lpMsgBuf, 0, NULL);
-	buf = ckalloc(TCL_INTEGER_SPACE + size + 1);
-	sprintf(buf, "%d %s", lastError, (char *)lpMsgBuf);
-#endif
-
 	Tcl_AppendResult(interp, "couldn't load library \"",
 		Tcl_GetString(pathPtr), "\": ", NULL);
 
@@ -185,24 +164,25 @@ TclpDlopen(
  *----------------------------------------------------------------------
  */
 
-void *
+static void *
 FindSymbol(
     Tcl_Interp *interp,
     Tcl_LoadHandle loadHandle,
     const char *symbol)
 {
+    HINSTANCE hInstance = (HINSTANCE) loadHandle->clientData;
     Tcl_PackageInitProc *proc = NULL;
-    HINSTANCE hInstance = (HINSTANCE)(loadHandle->clientData);
 
     /*
      * For each symbol, check for both Symbol and _Symbol, since Borland
      * generates C symbols with a leading '_' by default.
      */
 
-    proc = (void*) GetProcAddress(hInstance, symbol);
+    proc = (void *) GetProcAddress(hInstance, symbol);
     if (proc == NULL) {
 	Tcl_DString ds;
-	const char* sym2;
+	const char *sym2;
+
 	Tcl_DStringInit(&ds);
 	Tcl_DStringAppend(&ds, "_", 1);
 	sym2 = Tcl_DStringAppend(&ds, symbol, -1);
@@ -234,7 +214,7 @@ FindSymbol(
  *----------------------------------------------------------------------
  */
 
-void
+static void
 UnloadFile(
     Tcl_LoadHandle loadHandle)	/* loadHandle returned by a previous call to
 				 * TclpDlopen(). The loadHandle is a token
@@ -277,7 +257,7 @@ TclGuessPackageName(
 }
 
 /*
- *-----------------------------------------------------------------------------
+ *----------------------------------------------------------------------
  *
  * TclpTempFileNameForLibrary --
  *
@@ -287,86 +267,125 @@ TclGuessPackageName(
  *	Returns the constructed file name.
  *
  * On Windows, a DLL is identified by the final component of its path name.
- * Cross linking among DLL's (and hence, preloading) will not work unless
- * this name is preserved when copying a DLL from a VFS to a temp file for
- * preloading. For this reason, all DLLs in a given process are copied
- * to a temp directory, and their names are preserved.
+ * Cross linking among DLL's (and hence, preloading) will not work unless this
+ * name is preserved when copying a DLL from a VFS to a temp file for
+ * preloading. For this reason, all DLLs in a given process are copied to a
+ * temp directory, and their names are preserved.
  *
- *-----------------------------------------------------------------------------
+ *----------------------------------------------------------------------
  */
 
-Tcl_Obj*
-TclpTempFileNameForLibrary(Tcl_Interp* interp, /* Tcl interpreter */
-			   Tcl_Obj* path)      /* Path name of the DLL in
-						* the VFS */
+Tcl_Obj *
+TclpTempFileNameForLibrary(
+    Tcl_Interp *interp,		/* Tcl interpreter. */
+    Tcl_Obj *path)		/* Path name of the DLL in the VFS. */
 {
-    size_t nameLen;		/* Length of the temp folder name */
-    WCHAR name[MAX_PATH];	/* Path name of the temp folder */
-    BOOL status;		/* Status from Win32 API calls */
-    Tcl_Obj* fileName;		/* Name of the temp file */
-    Tcl_Obj* tail;		/* Tail of the source path */
+    Tcl_Obj *fileName;		/* Name of the temp file. */
+    Tcl_Obj *tail;		/* Tail of the source path. */
 
-    /*
-     * Determine the name of the directory to use, and create it.
-     * (Keep trying with new names until an attempt to create the directory
-     * succeeds)
-     */
-
-    nameLen = 0;
+    Tcl_MutexLock(&dllDirectoryNameMutex);
     if (dllDirectoryName == NULL) {
-	Tcl_MutexLock(&loadMutex);
-	if (dllDirectoryName == NULL) {
-	    nameLen = GetTempPathW(MAX_PATH, name);
-	    if (nameLen >= MAX_PATH-12) {
-		Tcl_SetErrno(ENAMETOOLONG);
-		nameLen = 0;
-	    } else {
-		wcscpy(name+nameLen, L"TCLXXXXXXXX");
-		nameLen += 11;
-	    }
-	    status = 1;
-	    if (nameLen != 0) {
-		DWORD id;
-		int i = 0;
-		id = GetCurrentProcessId();
-		for (;;) {
-		    DWORD lastError;
-		    wsprintfW(name+nameLen-8, L"%08x", id);
-		    status = CreateDirectoryW(name, NULL);
-		    if (status) {
-			break;
-		    }
-		    if ((lastError = GetLastError()) != ERROR_ALREADY_EXISTS) {
-			TclWinConvertError(lastError);
-			break;
-		    } else if (++i > 256) {
-			TclWinConvertError(lastError);
-			break;
-		    }
-		    id *= 16777619;
-		}
-	    }
-	    if (status != 0) {
-		dllDirectoryName = ckalloc((nameLen+1) * sizeof(WCHAR));
-		wcscpy(dllDirectoryName, name);
-	    }
+	if (InitDLLDirectoryName() == TCL_ERROR) {
+	    Tcl_AppendResult(interp, "couldn't create temporary directory: ",
+		    Tcl_PosixError(interp), NULL);
+	    Tcl_MutexUnlock(&dllDirectoryNameMutex);
+	    return NULL;
 	}
-	Tcl_MutexUnlock(&loadMutex);
-    }
-    if (dllDirectoryName == NULL) {
-	Tcl_AppendResult(interp, "couldn't create temporary directory: ",
-		Tcl_PosixError(interp), NULL);
     }
+    Tcl_MutexUnlock(&dllDirectoryNameMutex);
+
+    /*
+     * Now we know where to put temporary DLLs, construct the name.
+     */
+
     fileName = TclpNativeToNormalized(dllDirectoryName);
     tail = TclPathPart(interp, path, TCL_PATH_TAIL);
     if (tail == NULL) {
 	Tcl_DecrRefCount(fileName);
 	return NULL;
-    } else {
-	Tcl_AppendToObj(fileName, "/", 1);
-	Tcl_AppendObjToObj(fileName, tail);
-	return fileName;
     }
+    Tcl_AppendToObj(fileName, "/", 1);
+    Tcl_AppendObjToObj(fileName, tail);
+    return fileName;
+}
+
+/*
+ *----------------------------------------------------------------------
+ *
+ * InitDLLDirectoryName --
+ *
+ *	Helper for TclpTempFileNameForLibrary; builds a temporary directory
+ *	that is specific to the current process. Should only be called once
+ *	per process start. Caller must hold dllDirectoryNameMutex.
+ *
+ * Results:
+ *	Tcl result code.
+ *
+ * Side-effects:
+ *	Creates temp directory.
+ *	Allocates memory pointed to by dllDirectoryName.
+ *
+ *----------------------------------------------------------------------
+ * [Candidate for process global?]
+ */
+
+static int
+InitDLLDirectoryName(void)
+{
+    size_t nameLen;		/* Length of the temp folder name. */
+    WCHAR name[MAX_PATH];	/* Path name of the temp folder. */
+    DWORD id;			/* The process id. */
+    DWORD lastError;		/* Last error to happen in Win API. */
+    int i;
+
+    /*
+     * Determine the name of the directory to use, and create it.  (Keep
+     * trying with new names until an attempt to create the directory
+     * succeeds)
+     */
+
+    nameLen = GetTempPathW(MAX_PATH, name);
+    if (nameLen >= MAX_PATH-12) {
+	Tcl_SetErrno(ENAMETOOLONG);
+	return TCL_ERROR;
+    }
+
+    wcscpy(name+nameLen, L"TCLXXXXXXXX");
+    nameLen += 11;
+
+    id = GetCurrentProcessId();
+    lastError = ERROR_ALREADY_EXISTS;
+
+    for (i=0 ; i<256 ; i++) {
+	wsprintfW(name+nameLen-8, L"%08x", id);
+	if (CreateDirectoryW(name, NULL)) {
+	    /*
+	     * Issue: we don't schedule this directory for deletion by anyone.
+	     * Can we ask the OS to do this for us?  There appears to be
+	     * potential for using CreateFile (with the flag
+	     * FILE_FLAG_BACKUP_SEMANTICS) and RemoveDirectory to do this...
+	     */
+
+	    goto copyToGlobalBuffer;
+	}
+	lastError = GetLastError();
+	if (lastError != ERROR_ALREADY_EXISTS) {
+	    break;
+	}
+	id *= 16777619;
+    }
+
+    TclWinConvertError(lastError);
+    return TCL_ERROR;
+
+    /*
+     * Store our computed value in the global.
+     */
+
+  copyToGlobalBuffer:
+    dllDirectoryName = ckalloc((nameLen+1) * sizeof(WCHAR));
+    wcscpy(dllDirectoryName, name);
+    return TCL_OK;
 }
 
 /*