FileAPI: Split recursive remove into multiple async tasks

webkit/fileapi/remove_operation_delegate.cc

Index: webkit/fileapi/remove_operation_delegate.cc
diff --git a/webkit/fileapi/remove_operation_delegate.cc b/webkit/fileapi/remove_operation_delegate.cc
new file mode 100644
index 0000000000000000000000000000000000000000..3dafbdb04e08840513582e1525a06e8b6dd9bad3
--- /dev/null
+++ b/webkit/fileapi/remove_operation_delegate.cc
@@ -0,0 +1,166 @@
+// Copyright (c) 2013 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "webkit/fileapi/remove_operation_delegate.h"
+
+#include "base/bind.h"
+#include "webkit/fileapi/file_system_context.h"
+#include "webkit/fileapi/file_system_operation_context.h"
+#include "webkit/fileapi/local_file_system_operation.h"
+
+namespace fileapi {
+
+RemoveOperationDelegate::RemoveOperationDelegate(
+    LocalFileSystemOperation* original_operation,
+    const StatusCallback& callback)
+    : original_operation_(original_operation),
+      callback_(callback),
+      inflight_operations_(0) {
+}
+
+RemoveOperationDelegate::~RemoveOperationDelegate() {}
+
+void RemoveOperationDelegate::Run(const FileSystemURL& url) {
+  LocalFileSystemOperation* operation = NewOperation(url);
+  if (!operation)
+    return;
+  operation->RemoveFile(url, base::Bind(
+      &RemoveOperationDelegate::DidTryRemoveFile, AsWeakPtr(), url));
+}
+
+void RemoveOperationDelegate::RunRecursively(const FileSystemURL& url) {
+  DCHECK(pending_directories_.empty());
+  pending_directories_.push(url);
+  ProcessNextDirectory(base::PLATFORM_FILE_OK);
+}
+
+void RemoveOperationDelegate::DidTryRemoveFile(
+    const FileSystemURL& url,
+    base::PlatformFileError error) {
+  if (error == base::PLATFORM_FILE_OK ||
+      error != base::PLATFORM_FILE_ERROR_NOT_A_FILE) {
+    callback_.Run(error);
+    return;
+  }
+  LocalFileSystemOperation* operation = NewOperation(url);
+  if (!operation)
+    return;
+  operation->RemoveDirectory(url, callback_);
+}
+
+void RemoveOperationDelegate::ProcessNextDirectory(
+    base::PlatformFileError error) {
+  if (error != base::PLATFORM_FILE_OK) {
+    callback_.Run(error);
+    return;
+  }
+  if (inflight_operations_ > 0)
+    return;
+  if (pending_directories_.empty()) {
+    RemoveNextDirectory(error);
+    return;
+  }
+  FileSystemURL url = pending_directories_.front();
+  pending_directories_.pop();
+  LocalFileSystemOperation* operation = NewOperation(url);
+  if (!operation)
+    return;
+  inflight_operations_++;
+  operation->ReadDirectory(
+      url, base::Bind(&RemoveOperationDelegate::DidReadDirectory,
+                      AsWeakPtr(), url));
+}
+
+void RemoveOperationDelegate::DidReadDirectory(
+    const FileSystemURL& parent,
+    base::PlatformFileError error,
+    const FileEntryList& entries,
+    bool has_more) {
+  if (error != base::PLATFORM_FILE_OK) {
+    if (error == base::PLATFORM_FILE_ERROR_NOT_A_DIRECTORY) {
+      // The given path may have been a file, so try RemoveFile.
+      inflight_operations_--;
+      DCHECK_GE(inflight_operations_, 0);
+      RemoveFile(parent);
+      return;
+    }
+    callback_.Run(error);
+    return;
+  }
+  for (size_t i = 0; i < entries.size(); i++) {
+    FileSystemURL url = parent.WithPath(parent.path().Append(entries[i].name));
+    if (entries[i].is_directory) {
+      pending_directories_.push(url);
+      continue;
+    }
+    RemoveFile(url);
+  }
+  if (has_more)
+    return;
+
+  to_remove_directories_.push(parent);
+  inflight_operations_--;
+  DCHECK_GE(inflight_operations_, 0);
+  ProcessNextDirectory(base::PLATFORM_FILE_OK);
+}
+
+void RemoveOperationDelegate::RemoveFile(const FileSystemURL& url) {
+  LocalFileSystemOperation* operation = NewOperation(url);
+  if (!operation)
+    return;
+  inflight_operations_++;
+  operation->RemoveFile(url, base::Bind(
+      &RemoveOperationDelegate::DidRemoveFile, AsWeakPtr()));
+}
+
+void RemoveOperationDelegate::DidRemoveFile(base::PlatformFileError error) {
+  inflight_operations_--;
+  DCHECK_GE(inflight_operations_, 0);
+  if (error != base::PLATFORM_FILE_OK &&
+      error != base::PLATFORM_FILE_ERROR_NOT_FOUND) {
+    callback_.Run(error);
+    return;
+  }
+  ProcessNextDirectory(error);
+}
+
+void RemoveOperationDelegate::RemoveNextDirectory(
+    base::PlatformFileError error) {
+  DCHECK_EQ(0, inflight_operations_);
+  DCHECK(pending_directories_.empty());
+  if (error != base::PLATFORM_FILE_OK ||
+      to_remove_directories_.empty()) {
+    callback_.Run(error);
+    return;
+  }
+  FileSystemURL url = to_remove_directories_.top();
+  to_remove_directories_.pop();
+  LocalFileSystemOperation* operation = NewOperation(url);
+  if (!operation)
+    return;
+  operation->RemoveDirectory(url, base::Bind(
+      &RemoveOperationDelegate::RemoveNextDirectory,
+      AsWeakPtr()));
+}
+
+LocalFileSystemOperation* RemoveOperationDelegate::NewOperation(
+    const FileSystemURL& url) {
+  base::PlatformFileError error;
+  FileSystemOperation* operation = original_operation_->file_system_context()->
+      CreateFileSystemOperation(url, &error);
+  if (error != base::PLATFORM_FILE_OK) {
+    callback_.Run(error);
+    return NULL;
+  }
+  LocalFileSystemOperation* local_operation =
+      operation->AsLocalFileSystemOperation();
+  DCHECK(local_operation);
+
+  // Let the new operation inherit from the original operation.
+  local_operation->set_overriding_operation_context(
+      original_operation_->operation_context());
+  return local_operation;
+}
+
+}  // namespace fileapi