Bug 1819253 - Retry IOUtils.remove on E_ACCESSDENIED r=nika

Differential Revision: https://phabricator.services.mozilla.com/D171183

dom/chrome-webidl/IOUtils.webidl

@@ -576,6 +576,14 @@ dictionary RemoveOptions {
    * If true, and the target is a directory, recursively remove files.
    */
   boolean recursive = false;
+
+  /**
+   * If true, a failed delete on a readonly file will be retried by first
+   * removing the readonly attribute.
+   *
+   * Only has an effect on Windows.
+   */
+  boolean retryReadonly = false;
 };
 
 /**

dom/system/IOUtils.cpp

@@ -665,8 +665,9 @@ already_AddRefed<Promise> IOUtils::Remove(GlobalObject& aGlobal,
         DispatchAndResolve<Ok>(
             state->mEventQueue, promise,
             [file = std::move(file), ignoreAbsent = aOptions.mIgnoreAbsent,
-             recursive = aOptions.mRecursive]() {
-              return RemoveSync(file, ignoreAbsent, recursive);
+             recursive = aOptions.mRecursive,
+             retryReadonly = aOptions.mRetryReadonly]() {
+              return RemoveSync(file, ignoreAbsent, recursive, retryReadonly);
             });
       });
 }
@@ -1613,9 +1614,13 @@ Result<Ok, IOUtils::IOError> IOUtils::CopyOrMoveSync(CopyOrMoveFn aMethod,
 /* static */
 Result<Ok, IOUtils::IOError> IOUtils::RemoveSync(nsIFile* aFile,
                                                  bool aIgnoreAbsent,
-                                                 bool aRecursive) {
+                                                 bool aRecursive,
+                                                 bool aRetryReadonly) {
   MOZ_ASSERT(!NS_IsMainThread());
 
+  // Prevent an unused variable warning.
+  (void)aRetryReadonly;
+
   nsresult rv = aFile->Remove(aRecursive);
   if (aIgnoreAbsent && IsFileNotFound(rv)) {
     return Ok();
@@ -1634,6 +1639,17 @@ Result<Ok, IOUtils::IOError> IOUtils::RemoveSync(nsIFile* aFile,
           "Specify the `recursive: true` option to mitigate this error",
           aFile->HumanReadablePath().get()));
     }
+
+#ifdef XP_WIN
+
+    if (rv == NS_ERROR_FILE_ACCESS_DENIED && aRetryReadonly) {
+      MOZ_TRY(SetWindowsAttributesSync(aFile, 0, FILE_ATTRIBUTE_READONLY));
+      return RemoveSync(aFile, aIgnoreAbsent, aRecursive,
+                        /* aRetryReadonly = */ false);
+    }
+
+#endif
+
     return Err(err.WithMessage("Could not remove the file at %s",
                                aFile->HumanReadablePath().get()));
   }

dom/system/IOUtils.h

@@ -401,16 +401,20 @@ class IOUtils final {
   /**
    * Attempts to remove the file located at |aFile|.
    *
-   * @param aFile         The location of the file.
-   * @param aIgnoreAbsent If true, suppress errors due to an absent target file.
-   * @param aRecursive    If true, attempt to recursively remove descendant
-   *                      files. This option is safe to use even if the target
-   *                      is not a directory.
+   * @param aFile          The location of the file.
+   * @param aIgnoreAbsent  If true, suppress errors due to an absent target
+   * file.
+   * @param aRecursive     If true, attempt to recursively remove descendant
+   *                       files. This option is safe to use even if the target
+   *                       is not a directory.
+   * @param aRetryReadonly Retry a delete that failed with a NotAllowedError by
+   *                       first removing the readonly attribute. Only has an
+   *                       effect on Windows.
    *
    * @return Ok if the file was removed successfully, or an error.
    */
   static Result<Ok, IOError> RemoveSync(nsIFile* aFile, bool aIgnoreAbsent,
-                                        bool aRecursive);
+                                        bool aRecursive, bool aRetryReadonly);
 
   /**
    * Attempts to create a new directory at |aFile|.

dom/system/tests/ioutils/test_ioutils_remove.html

@@ -78,6 +78,33 @@
         "IOUtils::remove can recursively remove a directory"
       );
     });
+
+    if (Services.appinfo.OS === "WINNT") {
+      add_task(async function test_remove_retry_readonly() {
+
+        const tmpDir = PathUtils.join(PathUtils.tempDir, "test_ioutils_remove_retry_readonly.tmp.d");
+        const path = PathUtils.join(tmpDir, "file.txt");
+
+        await createDir(tmpDir);
+        await createFile(path, "");
+
+        await IOUtils.setWindowsAttributes(path, { readOnly: true });
+
+        await Assert.rejects(
+          IOUtils.remove(path),
+          /NotAllowedError/,
+          "Cannot remove a readonly file by default"
+        );
+
+        Assert.ok(await fileExists(path), "File should still exist");
+
+        await IOUtils.remove(path, { retryReadonly: true });
+
+        Assert.ok(!await fileExists(path), "File should not exist");
+
+        await IOUtils.remove(tmpDir);
+      });
+    }
   </script>
 </head>