Bug 775588 - Expose path to tmpdir, profiledir in OS.Constants and make sure that weird loaders that violate loading order do not segfault. r=khuey

--HG--
extra : rebase_source : 26df2463b84dd60ca50cc9c280f226ee692d2f4e

dom/system/OSFileConstants.cpp

@@ -33,6 +33,9 @@
 #include "nsXPCOMCIDInternal.h"
 #include "nsServiceManagerUtils.h"
 #include "nsString.h"
+#include "nsAutoPtr.h"
+#include "nsDirectoryServiceDefs.h"
+#include "nsAppDirectoryServiceDefs.h"
 
 #include "OSFileConstants.h"
 #include "nsIOSFileConstantsService.h"
@@ -53,10 +56,34 @@ namespace {
  */
 bool gInitialized = false;
 
+typedef struct {
+  /**
+   * The name of the directory holding all the libraries (libxpcom, libnss, etc.)
+   */
+  nsString libDir;
+  nsString tmpDir;
+  nsString profileDir;
+} Paths;
+
 /**
- * The name of the directory holding all the libraries (libxpcom, libnss, etc.)
+ * System directories.
  */
-nsString* gLibDirectory;
+Paths* gPaths = NULL;
+
+}
+
+/**
+ * Return the path to one of the special directories.
+ */
+nsresult GetPathToSpecialDir(const char *aKey, nsString& aOutPath)
+{
+  nsCOMPtr<nsIFile> file;
+  nsresult rv = NS_GetSpecialDirectory(aKey, getter_AddRefs(file));
+  if (NS_FAILED(rv) || !file) {
+    return rv;
+  }
+
+  return file->GetPath(aOutPath);
 }
 
 /**
@@ -72,23 +99,43 @@ nsresult InitOSFileConstants()
 
   gInitialized = true;
 
-  // Initialize gLibDirectory
-  nsCOMPtr<nsIFile> xpcomLib;
-  nsresult rv = NS_GetSpecialDirectory("XpcomLib", getter_AddRefs(xpcomLib));
-  if (NS_FAILED(rv) || !xpcomLib) {
-    return rv;
-  }
+  nsAutoPtr<Paths> paths(new Paths);
 
-  nsCOMPtr<nsIFile> libDir;
-  rv = xpcomLib->GetParent(getter_AddRefs(libDir));
+  // Initialize paths->libDir
+  nsCOMPtr<nsIFile> file;
+  nsresult rv = NS_GetSpecialDirectory("XpcomLib", getter_AddRefs(file));
   if (NS_FAILED(rv)) {
     return rv;
   }
 
-  gLibDirectory = new nsString();
-  return libDir->GetPath(*gLibDirectory);
+  nsCOMPtr<nsIFile> libDir;
+  rv = file->GetParent(getter_AddRefs(libDir));
+  if (NS_FAILED(rv)) {
+    return rv;
+  }
+
+  rv = libDir->GetPath(paths->libDir);
+  if (NS_FAILED(rv)) {
+    return rv;
+  }
+
+  rv = GetPathToSpecialDir(NS_OS_TEMP_DIR, paths->tmpDir);
+  if (NS_FAILED(rv)) {
+    return rv;
+  }
+
+  rv = GetPathToSpecialDir(NS_APP_USER_PROFILE_50_DIR, paths->profileDir);
+  if (NS_FAILED(rv)) {
+    return rv;
+  }
+
+  gPaths = paths.forget();
+  return NS_OK;
 }
 
+/**
+ * Perform the cleaning up that can only be executed on the main thread.
+ */
 void CleanupOSFileConstants()
 {
   MOZ_ASSERT(NS_IsMainThread());
@@ -97,7 +144,7 @@ void CleanupOSFileConstants()
   }
 
   gInitialized = false;
-  delete gLibDirectory;
+  delete gPaths;
 }
 
 
@@ -478,6 +525,17 @@ JSObject *GetOrCreateObjectProperty(JSContext *cx, JSObject *aObject,
   return JS_DefineObject(cx, aObject, aProperty, NULL, NULL, JSPROP_ENUMERATE);
 }
 
+/**
+ * Set a property of an object from a nsString.
+ */
+bool SetStringProperty(JSContext *cx, JSObject *aObject, const char *aProperty,
+                       const nsString aValue)
+{
+  JSString* strValue = JS_NewUCStringCopyZ(cx, aValue.get());
+  jsval valValue = STRING_TO_JSVAL(strValue);
+  return JS_SetProperty(cx, aObject, aProperty, &valValue);
+}
+
 /**
  * Define OS-specific constants.
  *
@@ -488,6 +546,16 @@ bool DefineOSFileConstants(JSContext *cx, JSObject *global)
 {
   MOZ_ASSERT(gInitialized);
 
+  if (gPaths == NULL) {
+    // If an initialization error was ignored, we may end up with
+    // |gInitialized == true| but |gPaths == NULL|. We cannot
+    // |MOZ_ASSERT| this, as this would kill precompile_cache.js,
+    // so we simply return an error.
+    JS_ReportErrorNumber(cx, js_GetErrorMessage, NULL,
+      JSMSG_CANT_OPEN, "OSFileConstants", "initialization has failed");
+    return false;
+  }
+
   JSObject *objOS;
   if (!(objOS = GetOrCreateObjectProperty(cx, global, "OS"))) {
     return false;
@@ -550,10 +618,9 @@ bool DefineOSFileConstants(JSContext *cx, JSObject *global)
     return false;
   }
 
-
   // Locate libxul
   {
-    nsAutoString xulPath(*gLibDirectory);
+    nsAutoString xulPath(gPaths->libDir);
 
     xulPath.Append(PR_GetDirectorySeparator());
 
@@ -568,13 +635,23 @@ bool DefineOSFileConstants(JSContext *cx, JSObject *global)
     xulPath.Append(NS_LITERAL_STRING(DLL_SUFFIX));
 #endif // defined(XP_MACOSX)
 
-    JSString* strPathToLibXUL = JS_NewUCStringCopyZ(cx, xulPath.get());
-    jsval valXul = STRING_TO_JSVAL(strPathToLibXUL);
-    if (!JS_SetProperty(cx, objPath, "libxul", &valXul)) {
+    if (!SetStringProperty(cx, objPath, "libxul", xulPath)) {
       return false;
     }
   }
 
+  if (!SetStringProperty(cx, objPath, "libDir", gPaths->libDir)) {
+    return false;
+  }
+
+  if (!SetStringProperty(cx, objPath, "tmpDir", gPaths->tmpDir)) {
+    return false;
+  }
+
+  if (!SetStringProperty(cx, objPath, "profileDir", gPaths->profileDir)) {
+    return false;
+  }
+
   return true;
 }