net: Make UploadDataStream::Init() asynchronous.

net/base/upload_data_stream.cc

 // Copyright (c) 2012 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 "net/base/upload_data_stream.h"
 
 #include "base/file_util.h"
 #include "base/logging.h"
 #include "base/threading/thread_restrictions.h"
+#include "base/threading/worker_pool.h"
+#include "base/tracked_objects.h"
 #include "net/base/file_stream.h"
 #include "net/base/io_buffer.h"
 #include "net/base/net_errors.h"
 
 namespace net {
 
+namespace {
+
+// Checks if any file in |upload_file| is modified since we initially
+// observed. Stores ERR_UPLOAD_FILE_CHANGED in |result| if such a
+// modification is detected. Otherwise, stores OK in |result|.
+void CheckModifiedFiles(scoped_refptr<UploadData> upload_data, int* result) {
+  // If the underlying file has been changed and the expected file
+  // modification time is set, treat it as error. Note that the expected
+  // modification time from WebKit is based on time_t precision. So we
+  // have to convert both to time_t to compare. This check is used for
+  // sliced files.
+  const std::vector<UploadData::Element>& elements = *upload_data->elements();
+  for (size_t i = 0; i < elements.size(); ++i) {
+    const UploadData::Element& element = elements[i];
+    if (element.type() == UploadData::TYPE_FILE &&
+        !element.expected_file_modification_time().is_null()) {
+      base::PlatformFileInfo info;
+      if (file_util::GetFileInfo(element.file_path(), &info) &&
+          element.expected_file_modification_time().ToTimeT() !=
+          info.last_modified.ToTimeT()) {
+        *result = ERR_UPLOAD_FILE_CHANGED;
+        return;
+      }
+    }
+  }
+  *result = OK;
+  return;
+}
+
+}  // namespace
+
 bool UploadDataStream::merge_chunks_ = true;
 
 UploadDataStream::UploadDataStream(UploadData* upload_data)
     : upload_data_(upload_data),
       element_index_(0),
       element_offset_(0),
       element_file_bytes_remaining_(0),
       total_size_(0),
       current_position_(0),
-      initialized_successfully_(false) {
+      initialized_successfully_(false),
+      weak_ptr_factory_(ALLOW_THIS_IN_INITIALIZER_LIST(this)) {
 }
 
 UploadDataStream::~UploadDataStream() {
 }
 
-int UploadDataStream::Init() {
+int UploadDataStream::Init(const CompletionCallback& on_completion) {
+  DCHECK(!initialized_successfully_);
+  DCHECK(user_callback_.is_null());
+
+  // Fast path. Initialize synchronously if the data is in memory.
+  if (upload_data_->IsInMemory())
+    return InitSync();
+
+  // The asynchronous initialization is performed in the following steps:
+  // 1. GetContentLength() computes the content length in the background.
+  // 2. OnGetContentLengthComplete() is called once it's done.
+  // 3. CheckModifiedFiles() checks the modified files in the background.
+  // 4. OnCheckModifiedFilesComplete() is called once it's done.
+  // 5. user_callback_ is run with the initialization result.
+  user_callback_ = on_completion;
+  upload_data_->GetContentLength(
+      base::Bind(&UploadDataStream::OnGetContentLengthComplete,
+                 weak_ptr_factory_.GetWeakPtr()));
+  return ERR_IO_PENDING;
+}
+
+int UploadDataStream::InitSync() {
   DCHECK(!initialized_successfully_);
 
-  {
-    base::ThreadRestrictions::ScopedAllowIO allow_io;
-    total_size_ = upload_data_->GetContentLengthSync();
-  }
+  total_size_ = upload_data_->GetContentLengthSync();
 
-  // If the underlying file has been changed and the expected file
-  // modification time is set, treat it as error. Note that the expected
-  // modification time from WebKit is based on time_t precision. So we
-  // have to convert both to time_t to compare. This check is used for
-  // sliced files.
-  const std::vector<UploadData::Element>& elements = *upload_data_->elements();
-  for (size_t i = 0; i < elements.size(); ++i) {
-    const UploadData::Element& element = elements[i];
-    if (element.type() == UploadData::TYPE_FILE &&
-        !element.expected_file_modification_time().is_null()) {
-      // Temporarily allow until fix: http://crbug.com/72001.
-      base::ThreadRestrictions::ScopedAllowIO allow_io;
-      base::PlatformFileInfo info;
-      if (file_util::GetFileInfo(element.file_path(), &info) &&
-          element.expected_file_modification_time().ToTimeT() !=
-          info.last_modified.ToTimeT()) {
-        return ERR_UPLOAD_FILE_CHANGED;
-      }
-    }
-  }
+  int result = OK;
+  CheckModifiedFiles(upload_data_, &result);
+  if (result != OK)
+    return result;
 
   initialized_successfully_ = true;
   return OK;
 }
 
 int UploadDataStream::Read(IOBuffer* buf, int buf_len) {
   std::vector<UploadData::Element>& elements = *upload_data_->elements();
 
   int bytes_copied = 0;
   while (bytes_copied < buf_len && element_index_ < elements.size()) {
@@ skipping 88 matching lines @@
   element_offset_ = 0;
   element_file_bytes_remaining_ = 0;
   if (element_file_stream_.get()) {
     // Temporarily allow until fix: http://crbug.com/72001.
     base::ThreadRestrictions::ScopedAllowIO allow_io;
     element_file_stream_->CloseSync();
     element_file_stream_.reset();
   }
 }
 
+void UploadDataStream::OnGetContentLengthComplete(uint64 content_length) {
+  total_size_ = content_length;
+  int* result = new int(OK);
+  const bool posted = base::WorkerPool::PostTaskAndReply(
+      FROM_HERE,
+      base::Bind(&CheckModifiedFiles, upload_data_, result),
+      base::Bind(&UploadDataStream::OnCheckModifiedFilesComplete,
+                 weak_ptr_factory_.GetWeakPtr(),
+                 base::Owned(result)),
+      true /* task_is_slow */);
+  DCHECK(posted);
+}
+
+void UploadDataStream::OnCheckModifiedFilesComplete(int* result) {
+  if (*result == OK)
+    initialized_successfully_ = true;
+
+  // Tell the caller of Init() that the initialization is done. Run() may
+  // triger other asynchronous operations so user_callback_ is reset before
+  // running it.
+  CompletionCallback copied_user_callback = user_callback_;
+  user_callback_.Reset();
+  copied_user_callback.Run(*result);
+}
+
 bool UploadDataStream::IsEOF() const {
   const std::vector<UploadData::Element>& elements = *upload_data_->elements();
 
   // Check if all elements are consumed.
   if (element_index_ == elements.size()) {
     // If the upload data is chunked, check if the last element is the
     // last chunk.
     if (!upload_data_->is_chunked() ||
         (!elements.empty() && elements.back().is_last_chunk())) {
       return true;
     }
   }
   return false;
 }
 
 bool UploadDataStream::IsInMemory() const {
   DCHECK(initialized_successfully_);
 
   return upload_data_->IsInMemory();
 }
 
 }  // namespace net