// Copyright (c) 2006-2010 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/disk_cache/file.h"
#include "base/file_path.h"
#include "base/lazy_instance.h"
#include "base/message_loop.h"
#include "net/disk_cache/disk_cache.h"
namespace {
// Structure used for asynchronous operations.
struct MyOverlapped {
MyOverlapped(disk_cache::File* file, size_t offset,
disk_cache::FileIOCallback* callback);
~MyOverlapped() {}
OVERLAPPED* overlapped() {
return &context_.overlapped;
}
MessageLoopForIO::IOContext context_;
scoped_refptr<disk_cache::File> file_;
disk_cache::FileIOCallback* callback_;
};
COMPILE_ASSERT(!offsetof(MyOverlapped, context_), starts_with_overlapped);
// Helper class to handle the IO completion notifications from the message loop.
class CompletionHandler : public MessageLoopForIO::IOHandler {
virtual void OnIOCompleted(MessageLoopForIO::IOContext* context,
DWORD actual_bytes, DWORD error);
};
static base::LazyInstance<CompletionHandler> g_completion_handler(
base::LINKER_INITIALIZED);
void CompletionHandler::OnIOCompleted(MessageLoopForIO::IOContext* context,
DWORD actual_bytes, DWORD error) {
MyOverlapped* data = reinterpret_cast<MyOverlapped*>(context);
if (error) {
DCHECK(!actual_bytes);
actual_bytes = static_cast<DWORD>(-1);
NOTREACHED();
}
if (data->callback_)
data->callback_->OnFileIOComplete(static_cast<int>(actual_bytes));
delete data;
}
MyOverlapped::MyOverlapped(disk_cache::File* file, size_t offset,
disk_cache::FileIOCallback* callback) {
memset(this, 0, sizeof(*this));
context_.handler = g_completion_handler.Pointer();
context_.overlapped.Offset = static_cast<DWORD>(offset);
file_ = file;
callback_ = callback;
}
} // namespace
namespace disk_cache {
File::File(base::PlatformFile file)
: init_(true), mixed_(true), platform_file_(INVALID_HANDLE_VALUE),
sync_platform_file_(file) {
}
bool File::Init(const FilePath& name) {
DCHECK(!init_);
if (init_)
return false;
DWORD sharing = FILE_SHARE_READ | FILE_SHARE_WRITE | FILE_SHARE_DELETE;
DWORD access = GENERIC_READ | GENERIC_WRITE | DELETE;
platform_file_ = CreateFile(name.value().c_str(), access, sharing, NULL,
OPEN_EXISTING, FILE_FLAG_OVERLAPPED, NULL);
if (INVALID_HANDLE_VALUE == platform_file_)
return false;
MessageLoopForIO::current()->RegisterIOHandler(
platform_file_, g_completion_handler.Pointer());
init_ = true;
sync_platform_file_ = CreateFile(name.value().c_str(), access, sharing, NULL,
OPEN_EXISTING, 0, NULL);
if (INVALID_HANDLE_VALUE == sync_platform_file_)
return false;
return true;
}
File::~File() {
if (!init_)
return;
if (INVALID_HANDLE_VALUE != platform_file_)
CloseHandle(platform_file_);
if (INVALID_HANDLE_VALUE != sync_platform_file_)
CloseHandle(sync_platform_file_);
}
base::PlatformFile File::platform_file() const {
DCHECK(init_);
return (INVALID_HANDLE_VALUE == platform_file_) ? sync_platform_file_ :
platform_file_;
}
bool File::IsValid() const {
if (!init_)
return false;
return (INVALID_HANDLE_VALUE != platform_file_ ||
INVALID_HANDLE_VALUE != sync_platform_file_);
}
bool File::Read(void* buffer, size_t buffer_len, size_t offset) {
DCHECK(init_);
if (buffer_len > ULONG_MAX || offset > LONG_MAX)
return false;
DWORD ret = SetFilePointer(sync_platform_file_, static_cast<LONG>(offset),
NULL, FILE_BEGIN);
if (INVALID_SET_FILE_POINTER == ret)
return false;
DWORD actual;
DWORD size = static_cast<DWORD>(buffer_len);
if (!ReadFile(sync_platform_file_, buffer, size, &actual, NULL))
return false;
return actual == size;
}
bool File::Write(const void* buffer, size_t buffer_len, size_t offset) {
DCHECK(init_);
if (buffer_len > ULONG_MAX || offset > ULONG_MAX)
return false;
DWORD ret = SetFilePointer(sync_platform_file_, static_cast<LONG>(offset),
NULL, FILE_BEGIN);
if (INVALID_SET_FILE_POINTER == ret)
return false;
DWORD actual;
DWORD size = static_cast<DWORD>(buffer_len);
if (!WriteFile(sync_platform_file_, buffer, size, &actual, NULL))
return false;
return actual == size;
}
// We have to increase the ref counter of the file before performing the IO to
// prevent the completion to happen with an invalid handle (if the file is
// closed while the IO is in flight).
bool File::Read(void* buffer, size_t buffer_len, size_t offset,
FileIOCallback* callback, bool* completed) {
DCHECK(init_);
if (!callback) {
if (completed)
*completed = true;
return Read(buffer, buffer_len, offset);
}
if (buffer_len > ULONG_MAX || offset > ULONG_MAX)
return false;
MyOverlapped* data = new MyOverlapped(this, offset, callback);
DWORD size = static_cast<DWORD>(buffer_len);
DWORD actual;
if (!ReadFile(platform_file_, buffer, size, &actual, data->overlapped())) {
*completed = false;
if (GetLastError() == ERROR_IO_PENDING)
return true;
delete data;
return false;
}
// The operation completed already. We'll be called back anyway.
*completed = (actual == size);
DCHECK(actual == size);
data->callback_ = NULL;
data->file_ = NULL; // There is no reason to hold on to this anymore.
return *completed;
}
bool File::Write(const void* buffer, size_t buffer_len, size_t offset,
FileIOCallback* callback, bool* completed) {
DCHECK(init_);
if (!callback) {
if (completed)
*completed = true;
return Write(buffer, buffer_len, offset);
}
return AsyncWrite(buffer, buffer_len, offset, callback, completed);
}
bool File::AsyncWrite(const void* buffer, size_t buffer_len, size_t offset,
FileIOCallback* callback, bool* completed) {
DCHECK(init_);
DCHECK(callback);
DCHECK(completed);
if (buffer_len > ULONG_MAX || offset > ULONG_MAX)
return false;
MyOverlapped* data = new MyOverlapped(this, offset, callback);
DWORD size = static_cast<DWORD>(buffer_len);
DWORD actual;
if (!WriteFile(platform_file_, buffer, size, &actual, data->overlapped())) {
*completed = false;
if (GetLastError() == ERROR_IO_PENDING)
return true;
delete data;
return false;
}
// The operation completed already. We'll be called back anyway.
*completed = (actual == size);
DCHECK(actual == size);
data->callback_ = NULL;
data->file_ = NULL; // There is no reason to hold on to this anymore.
return *completed;
}
bool File::SetLength(size_t length) {
DCHECK(init_);
if (length > ULONG_MAX)
return false;
DWORD size = static_cast<DWORD>(length);
HANDLE file = platform_file();
if (INVALID_SET_FILE_POINTER == SetFilePointer(file, size, NULL, FILE_BEGIN))
return false;
return TRUE == SetEndOfFile(file);
}
size_t File::GetLength() {
DCHECK(init_);
LARGE_INTEGER size;
HANDLE file = platform_file();
if (!GetFileSizeEx(file, &size))
return 0;
if (size.HighPart)
return ULONG_MAX;
return static_cast<size_t>(size.LowPart);
}
// Static.
void File::WaitForPendingIO(int* num_pending_io) {
while (*num_pending_io) {
// Asynchronous IO operations may be in flight and the completion may end
// up calling us back so let's wait for them.
MessageLoopForIO::IOHandler* handler = g_completion_handler.Pointer();
MessageLoopForIO::current()->WaitForIOCompletion(100, handler);
}
}
} // namespace disk_cache