net: Make UploadDataStream::Init() asynchronous.

net/base/upload_file_element_reader.cc

Index: net/base/upload_file_element_reader.cc
diff --git a/net/base/upload_file_element_reader.cc b/net/base/upload_file_element_reader.cc
index b71c0225b8acb32b3c96a8cd81fc350866e74434..86be79d15095a58996d03d44c57abf0874ee3828 100644
--- a/net/base/upload_file_element_reader.cc
+++ b/net/base/upload_file_element_reader.cc
@@ -4,8 +4,11 @@
 
 #include "net/base/upload_file_element_reader.h"
 
+#include "base/bind.h"
 #include "base/file_util.h"
+#include "base/location.h"
 #include "base/threading/thread_restrictions.h"
+#include "base/threading/worker_pool.h"
 #include "net/base/file_stream.h"
 #include "net/base/net_errors.h"
 
@@ -17,6 +20,58 @@ namespace {
 // UploadFileElementReader::GetContentLength() when set to non-zero.
 uint64 overriding_content_length = 0;
 
+// This method is used to implement Init().
+void InitInternal(const FilePath& path,
+                  uint64 range_offset,
+                  uint64 range_length,
+                  const base::Time& expected_modification_time,
+                  scoped_ptr<FileStream>* out_file_stream,
+                  uint64* out_content_length,
+                  int* out_result) {
+  scoped_ptr<FileStream> file_stream(new FileStream(NULL));
+  int64 rv = file_stream->OpenSync(
+      path, base::PLATFORM_FILE_OPEN | base::PLATFORM_FILE_READ);
+  if (rv != OK) {
+    // If the file can't be opened, we'll just upload an empty file.
+    DLOG(WARNING) << "Failed to open \"" << path.value()
+                  << "\" for reading: " << rv;
+    file_stream.reset();
+  } else if (range_offset) {
+    rv = file_stream->SeekSync(FROM_BEGIN, range_offset);
+    if (rv < 0) {
+      DLOG(WARNING) << "Failed to seek \"" << path.value()
+                    << "\" to offset: " << range_offset << " (" << rv << ")";
+      file_stream->CloseSync();
+      file_stream.reset();
+    }
+  }
+
+  int64 length = 0;
+  if (file_stream.get() &&
+      file_util::GetFileSize(path, &length) &&
+      range_offset < static_cast<uint64>(length)) {
+    // Compensate for the offset.
+    length = std::min(length - range_offset, range_length);
+  }
+  *out_content_length = length;
+  out_file_stream->swap(file_stream);
+
+  // 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.
+  if (!expected_modification_time.is_null()) {
+    base::PlatformFileInfo info;
+    if (file_util::GetFileInfo(path, &info) &&
+        expected_modification_time.ToTimeT() != info.last_modified.ToTimeT()) {
+      *out_result = ERR_UPLOAD_FILE_CHANGED;
+      return;
+    }
+  }
+
+  *out_result = OK;
+}
+
 }  // namespace
 
 UploadFileElementReader::UploadFileElementReader(
@@ -29,7 +84,8 @@ UploadFileElementReader::UploadFileElementReader(
       range_length_(range_length),
       expected_modification_time_(expected_modification_time),
       content_length_(0),
-      bytes_remaining_(0) {
+      bytes_remaining_(0),
+      weak_ptr_factory_(this) {
 }
 
 UploadFileElementReader::~UploadFileElementReader() {
@@ -39,56 +95,42 @@ UploadFileElementReader::~UploadFileElementReader() {
     file_stream_->CloseSync();
 }
 
+int UploadFileElementReader::Init(const CompletionCallback& callback) {
+  scoped_ptr<FileStream>* file_stream = new scoped_ptr<FileStream>;
+  uint64* content_length = new uint64;
+  int* result = new int;
+  const bool posted = base::WorkerPool::PostTaskAndReply(
+      FROM_HERE,
+      base::Bind(&InitInternal,
+                 path_,
+                 range_offset_,
+                 range_length_,
+                 expected_modification_time_,
+                 file_stream,
+                 content_length,
+                 result),
+      base::Bind(&UploadFileElementReader::OnInitCompleted,
+                 weak_ptr_factory_.GetWeakPtr(),
+                 base::Owned(file_stream),
+                 base::Owned(content_length),
+                 base::Owned(result),
+                 callback),
+      true /* task_is_slow */);
+  DCHECK(posted);
+  return ERR_IO_PENDING;
+}
+
 int UploadFileElementReader::InitSync() {
   // Temporarily allow until fix: http://crbug.com/72001.
   base::ThreadRestrictions::ScopedAllowIO allow_io;
 
-  scoped_ptr<FileStream> file_stream(new FileStream(NULL));
-  int64 rv = file_stream->OpenSync(
-      path_, base::PLATFORM_FILE_OPEN | base::PLATFORM_FILE_READ);
-  if (rv != OK) {
-    // If the file can't be opened, we'll just upload an empty file.
-    DLOG(WARNING) << "Failed to open \"" << path_.value()
-                  << "\" for reading: " << rv;
-    file_stream.reset();
-  }
-  if (file_stream.get() && range_offset_) {
-    rv = file_stream->SeekSync(FROM_BEGIN, range_offset_);
-    if (rv < 0) {
-      DLOG(WARNING) << "Failed to seek \"" << path_.value()
-                    << "\" to offset: " << range_offset_ << " (" << rv
-                    << ")";
-      file_stream->CloseSync();
-      file_stream.reset();
-    }
-  }
-  file_stream_.reset(file_stream.release());
-
-  int64 length = 0;
-  if (file_stream_.get() &&
-      file_util::GetFileSize(path_, &length) &&
-      range_offset_ < static_cast<uint64>(length)) {
-    // Compensate for the offset.
-    length = std::min(length - range_offset_, range_length_);
-  }
-  content_length_ = length;
-  bytes_remaining_ = GetContentLength();
-
-  // 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.
-  if (!expected_modification_time_.is_null()) {
-    base::PlatformFileInfo info;
-    if (file_util::GetFileInfo(path_, &info) &&
-        expected_modification_time_.ToTimeT() !=
-        info.last_modified.ToTimeT()) {
-      return ERR_UPLOAD_FILE_CHANGED;
-    }
-  }
-
-  return OK;
+  scoped_ptr<FileStream> file_stream;
+  uint64 content_length = 0;
+  int result = OK;
+  InitInternal(path_, range_offset_, range_length_, expected_modification_time_,
+               &file_stream, &content_length, &result);
+  OnInitCompleted(&file_stream, &content_length, &result, CompletionCallback());
+  return result;
 }
 
 uint64 UploadFileElementReader::GetContentLength() const {
@@ -129,6 +171,18 @@ int UploadFileElementReader::ReadSync(char* buf, int buf_length) {
   return num_bytes_to_read;
 }
 
+void UploadFileElementReader::OnInitCompleted(
+    scoped_ptr<FileStream>* file_stream,
+    uint64* content_length,
+    int* result,
+    const CompletionCallback& callback) {
+  file_stream_.swap(*file_stream);
+  content_length_ = *content_length;
+  bytes_remaining_ = GetContentLength();
+  if (!callback.is_null())
+    callback.Run(*result);
+}
+
 UploadFileElementReader::ScopedOverridingContentLengthForTests::
 ScopedOverridingContentLengthForTests(uint64 value) {
   overriding_content_length = value;