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// Copyright (c) 2008 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/file_input_stream.h"
#include <windows.h>
#include "base/logging.h"
#include "base/message_loop.h"
#include "net/base/net_errors.h"
namespace net {
// Ensure that we can just use our Whence values directly.
COMPILE_ASSERT(FROM_BEGIN == FILE_BEGIN, bad_whence_begin);
COMPILE_ASSERT(FROM_CURRENT == FILE_CURRENT, bad_whence_current);
COMPILE_ASSERT(FROM_END == FILE_END, bad_whence_end);
static void SetOffset(OVERLAPPED* overlapped, const LARGE_INTEGER& offset) {
overlapped->Offset = offset.LowPart;
overlapped->OffsetHigh = offset.HighPart;
}
static void IncrementOffset(OVERLAPPED* overlapped, DWORD count) {
LARGE_INTEGER offset;
offset.LowPart = overlapped->Offset;
offset.HighPart = overlapped->OffsetHigh;
offset.QuadPart += static_cast<LONGLONG>(count);
SetOffset(overlapped, offset);
}
static int MapErrorCode(DWORD err) {
switch (err) {
case ERROR_FILE_NOT_FOUND:
case ERROR_PATH_NOT_FOUND:
return ERR_FILE_NOT_FOUND;
case ERROR_ACCESS_DENIED:
return ERR_ACCESS_DENIED;
case ERROR_SUCCESS:
return OK;
default:
LOG(WARNING) << "Unknown error " << err << " mapped to net::ERR_FAILED";
return ERR_FAILED;
}
}
// FileInputStream::AsyncContext ----------------------------------------------
class FileInputStream::AsyncContext : public MessageLoopForIO::IOHandler {
public:
AsyncContext(FileInputStream* owner)
: owner_(owner), overlapped_(), callback_(NULL) {
overlapped_.hEvent = CreateEvent(NULL, TRUE, FALSE, NULL);
}
~AsyncContext() {
if (callback_)
MessageLoopForIO::current()->RegisterIOContext(&overlapped_, NULL);
CloseHandle(overlapped_.hEvent);
}
void IOCompletionIsPending(CompletionCallback* callback);
OVERLAPPED* overlapped() { return &overlapped_; }
CompletionCallback* callback() const { return callback_; }
private:
// MessageLoopForIO::IOHandler implementation:
virtual void OnIOCompleted(OVERLAPPED* context, DWORD bytes_read,
DWORD error);
FileInputStream* owner_;
OVERLAPPED overlapped_;
CompletionCallback* callback_;
};
void FileInputStream::AsyncContext::IOCompletionIsPending(
CompletionCallback* callback) {
DCHECK(!callback_);
callback_ = callback;
MessageLoopForIO::current()->RegisterIOContext(&overlapped_, this);
}
void FileInputStream::AsyncContext::OnIOCompleted(OVERLAPPED* context,
DWORD bytes_read,
DWORD error) {
DCHECK(&overlapped_ == context);
DCHECK(callback_);
MessageLoopForIO::current()->RegisterIOContext(&overlapped_, NULL);
HANDLE handle = owner_->handle_;
int result = static_cast<int>(bytes_read);
if (error && error != ERROR_HANDLE_EOF)
result = MapErrorCode(error);
if (bytes_read)
IncrementOffset(&overlapped_, bytes_read);
CompletionCallback* temp = NULL;
std::swap(temp, callback_);
temp->Run(result);
}
// FileInputStream ------------------------------------------------------------
FileInputStream::FileInputStream() : handle_(INVALID_HANDLE_VALUE) {
}
FileInputStream::~FileInputStream() {
Close();
}
void FileInputStream::Close() {
if (handle_ != INVALID_HANDLE_VALUE) {
CloseHandle(handle_);
handle_ = INVALID_HANDLE_VALUE;
}
async_context_.reset();
}
int FileInputStream::Open(const std::wstring& path, bool asynchronous_mode) {
if (IsOpen()) {
DLOG(FATAL) << "File is already open!";
return ERR_UNEXPECTED;
}
// Optimize for streaming, not seeking. If someone does a lot of random
// access operations, then we should consider revising this.
DWORD create_file_flags = FILE_FLAG_SEQUENTIAL_SCAN;
if (asynchronous_mode)
create_file_flags |= FILE_FLAG_OVERLAPPED;
handle_ =
CreateFile(path.c_str(), GENERIC_READ | SYNCHRONIZE,
FILE_SHARE_READ | FILE_SHARE_WRITE | FILE_SHARE_DELETE,
NULL, OPEN_EXISTING, create_file_flags, NULL);
if (handle_ == INVALID_HANDLE_VALUE) {
DWORD error = GetLastError();
LOG(WARNING) << "Failed to open file: " << error;
return MapErrorCode(error);
}
if (asynchronous_mode) {
async_context_.reset(new AsyncContext(this));
MessageLoopForIO::current()->RegisterIOHandler(handle_,
async_context_.get());
}
return OK;
}
bool FileInputStream::IsOpen() const {
return handle_ != INVALID_HANDLE_VALUE;
}
int64 FileInputStream::Seek(Whence whence, int64 offset) {
if (!IsOpen())
return ERR_UNEXPECTED;
DCHECK(!async_context_.get() || !async_context_->callback());
LARGE_INTEGER distance, result;
distance.QuadPart = offset;
DWORD move_method = static_cast<DWORD>(whence);
if (!SetFilePointerEx(handle_, distance, &result, move_method)) {
DWORD error = GetLastError();
LOG(WARNING) << "SetFilePointerEx failed: " << error;
return MapErrorCode(error);
}
if (async_context_.get())
SetOffset(async_context_->overlapped(), result);
return result.QuadPart;
}
int64 FileInputStream::Available() {
if (!IsOpen())
return ERR_UNEXPECTED;
int64 cur_pos = Seek(FROM_CURRENT, 0);
if (cur_pos < 0)
return cur_pos;
LARGE_INTEGER file_size;
if (!GetFileSizeEx(handle_, &file_size)) {
DWORD error = GetLastError();
LOG(WARNING) << "GetFileSizeEx failed: " << error;
return MapErrorCode(error);
}
return file_size.QuadPart - cur_pos;
}
int FileInputStream::Read(
char* buf, int buf_len, CompletionCallback* callback) {
if (!IsOpen())
return ERR_UNEXPECTED;
OVERLAPPED* overlapped = NULL;
if (async_context_.get()) {
DCHECK(!async_context_->callback());
overlapped = async_context_->overlapped();
}
int rv;
DWORD bytes_read;
if (!ReadFile(handle_, buf, buf_len, &bytes_read, overlapped)) {
DWORD error = GetLastError();
if (async_context_.get() && error == ERROR_IO_PENDING) {
async_context_->IOCompletionIsPending(callback);
rv = ERR_IO_PENDING;
} else if (error == ERROR_HANDLE_EOF) {
rv = 0; // Report EOF by returning 0 bytes read.
} else {
LOG(WARNING) << "ReadFile failed: " << error;
rv = MapErrorCode(error);
}
} else {
if (overlapped)
IncrementOffset(overlapped, bytes_read);
rv = static_cast<int>(bytes_read);
}
return rv;
}
} // namespace net
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