// Copyright (c) 2011 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.
// For loading files, we make use of overlapped i/o to ensure that reading from
// the filesystem (e.g., a network filesystem) does not block the calling
// thread. An alternative approach would be to use a background thread or pool
// of threads, but it seems better to leverage the operating system's ability
// to do background file reads for us.
//
// Since overlapped reads require a 'static' buffer for the duration of the
// asynchronous read, the URLRequestFileJob keeps a buffer as a member var. In
// URLRequestFileJob::Read, data is simply copied from the object's buffer into
// the given buffer. If there is no data to copy, the URLRequestFileJob
// attempts to read more from the file to fill its buffer. If reading from the
// file does not complete synchronously, then the URLRequestFileJob waits for a
// signal from the OS that the overlapped read has completed. It does so by
// leveraging the MessageLoop::WatchObject API.
#include "net/url_request/url_request_file_job.h"
#include "base/compiler_specific.h"
#include "base/message_loop.h"
#include "base/platform_file.h"
#include "base/string_util.h"
#include "base/synchronization/lock.h"
#include "base/threading/worker_pool.h"
#include "base/threading/thread_restrictions.h"
#include "build/build_config.h"
#include "googleurl/src/gurl.h"
#include "net/base/io_buffer.h"
#include "net/base/load_flags.h"
#include "net/base/mime_util.h"
#include "net/base/net_errors.h"
#include "net/base/net_util.h"
#include "net/http/http_util.h"
#include "net/url_request/url_request.h"
#include "net/url_request/url_request_error_job.h"
#include "net/url_request/url_request_file_dir_job.h"
namespace net {
#if defined(OS_WIN)
class URLRequestFileJob::AsyncResolver
: public base::RefCountedThreadSafe<URLRequestFileJob::AsyncResolver> {
public:
explicit AsyncResolver(URLRequestFileJob* owner)
: owner_(owner), owner_loop_(MessageLoop::current()) {
}
void Resolve(const FilePath& file_path) {
base::PlatformFileInfo file_info;
bool exists = file_util::GetFileInfo(file_path, &file_info);
base::AutoLock locked(lock_);
if (owner_loop_) {
owner_loop_->PostTask(FROM_HERE, NewRunnableMethod(
this, &AsyncResolver::ReturnResults, exists, file_info));
}
}
void Cancel() {
owner_ = NULL;
base::AutoLock locked(lock_);
owner_loop_ = NULL;
}
private:
friend class base::RefCountedThreadSafe<URLRequestFileJob::AsyncResolver>;
~AsyncResolver() {}
void ReturnResults(bool exists, const base::PlatformFileInfo& file_info) {
if (owner_)
owner_->DidResolve(exists, file_info);
}
URLRequestFileJob* owner_;
base::Lock lock_;
MessageLoop* owner_loop_;
};
#endif
URLRequestFileJob::URLRequestFileJob(URLRequest* request,
const FilePath& file_path)
: URLRequestJob(request),
file_path_(file_path),
ALLOW_THIS_IN_INITIALIZER_LIST(
io_callback_(this, &URLRequestFileJob::DidRead)),
is_directory_(false),
remaining_bytes_(0),
ALLOW_THIS_IN_INITIALIZER_LIST(method_factory_(this)) {
}
// static
URLRequestJob* URLRequestFileJob::Factory(URLRequest* request,
const std::string& scheme) {
FilePath file_path;
const bool is_file = FileURLToFilePath(request->url(), &file_path);
#if defined(OS_CHROMEOS)
// Check file access.
if (AccessDisabled(file_path))
return new URLRequestErrorJob(request, ERR_ACCESS_DENIED);
#endif
// We need to decide whether to create URLRequestFileJob for file access or
// URLRequestFileDirJob for directory access. To avoid accessing the
// filesystem, we only look at the path string here.
// The code in the URLRequestFileJob::Start() method discovers that a path,
// which doesn't end with a slash, should really be treated as a directory,
// and it then redirects to the URLRequestFileDirJob.
if (is_file &&
file_util::EndsWithSeparator(file_path) &&
file_path.IsAbsolute())
return new URLRequestFileDirJob(request, file_path);
// Use a regular file request job for all non-directories (including invalid
// file names).
return new URLRequestFileJob(request, file_path);
}
#if defined(OS_CHROMEOS)
static const char* const kLocalAccessWhiteList[] = {
"/home/chronos/user/Downloads",
"/media",
"/opt/oem",
"/usr/share/chromeos-assets",
"/tmp",
"/var/log",
};
// static
bool URLRequestFileJob::AccessDisabled(const FilePath& file_path) {
if (URLRequest::IsFileAccessAllowed()) { // for tests.
return false;
}
for (size_t i = 0; i < arraysize(kLocalAccessWhiteList); ++i) {
const FilePath white_listed_path(kLocalAccessWhiteList[i]);
// FilePath::operator== should probably handle trailing seperators.
if (white_listed_path == file_path.StripTrailingSeparators() ||
white_listed_path.IsParent(file_path)) {
return false;
}
}
return true;
}
#endif
void URLRequestFileJob::Start() {
#if defined(OS_WIN)
// Resolve UNC paths on a background thread.
if (!file_path_.value().compare(0, 2, L"\\\\")) {
DCHECK(!async_resolver_);
async_resolver_ = new AsyncResolver(this);
base::WorkerPool::PostTask(FROM_HERE, NewRunnableMethod(
async_resolver_.get(), &AsyncResolver::Resolve, file_path_), true);
return;
}
#endif
// URL requests should not block on the disk!
// http://code.google.com/p/chromium/issues/detail?id=59849
bool exists;
base::PlatformFileInfo file_info;
{
base::ThreadRestrictions::ScopedAllowIO allow_io;
exists = file_util::GetFileInfo(file_path_, &file_info);
}
// Continue asynchronously.
MessageLoop::current()->PostTask(
FROM_HERE,
method_factory_.NewRunnableMethod(
&URLRequestFileJob::DidResolve, exists, file_info));
}
void URLRequestFileJob::Kill() {
stream_.Close();
#if defined(OS_WIN)
if (async_resolver_) {
async_resolver_->Cancel();
async_resolver_ = NULL;
}
#endif
URLRequestJob::Kill();
method_factory_.RevokeAll();
}
bool URLRequestFileJob::ReadRawData(IOBuffer* dest, int dest_size,
int *bytes_read) {
DCHECK_NE(dest_size, 0);
DCHECK(bytes_read);
DCHECK_GE(remaining_bytes_, 0);
if (remaining_bytes_ < dest_size)
dest_size = static_cast<int>(remaining_bytes_);
// If we should copy zero bytes because |remaining_bytes_| is zero, short
// circuit here.
if (!dest_size) {
*bytes_read = 0;
return true;
}
int rv = stream_.Read(dest->data(), dest_size, &io_callback_);
if (rv >= 0) {
// Data is immediately available.
*bytes_read = rv;
remaining_bytes_ -= rv;
DCHECK_GE(remaining_bytes_, 0);
return true;
}
// Otherwise, a read error occured. We may just need to wait...
if (rv == ERR_IO_PENDING) {
SetStatus(URLRequestStatus(URLRequestStatus::IO_PENDING, 0));
} else {
NotifyDone(URLRequestStatus(URLRequestStatus::FAILED, rv));
}
return false;
}
bool URLRequestFileJob::IsRedirectResponse(GURL* location,
int* http_status_code) {
if (is_directory_) {
// This happens when we discovered the file is a directory, so needs a
// slash at the end of the path.
std::string new_path = request_->url().path();
new_path.push_back('/');
GURL::Replacements replacements;
replacements.SetPathStr(new_path);
*location = request_->url().ReplaceComponents(replacements);
*http_status_code = 301; // simulate a permanent redirect
return true;
}
#if defined(OS_WIN)
// Follow a Windows shortcut.
// We just resolve .lnk file, ignore others.
if (!LowerCaseEqualsASCII(file_path_.Extension(), ".lnk"))
return false;
FilePath new_path = file_path_;
bool resolved;
resolved = file_util::ResolveShortcut(&new_path);
// If shortcut is not resolved succesfully, do not redirect.
if (!resolved)
return false;
*location = FilePathToFileURL(new_path);
*http_status_code = 301;
return true;
#else
return false;
#endif
}
Filter* URLRequestFileJob::SetupFilter() const {
// Bug 9936 - .svgz files needs to be decompressed.
return LowerCaseEqualsASCII(file_path_.Extension(), ".svgz")
? Filter::GZipFactory() : NULL;
}
bool URLRequestFileJob::GetMimeType(std::string* mime_type) const {
// URL requests should not block on the disk! On Windows this goes to the
// registry.
// http://code.google.com/p/chromium/issues/detail?id=59849
base::ThreadRestrictions::ScopedAllowIO allow_io;
DCHECK(request_);
return GetMimeTypeFromFile(file_path_, mime_type);
}
void URLRequestFileJob::SetExtraRequestHeaders(
const HttpRequestHeaders& headers) {
std::string range_header;
if (headers.GetHeader(HttpRequestHeaders::kRange, &range_header)) {
// We only care about "Range" header here.
std::vector<HttpByteRange> ranges;
if (HttpUtil::ParseRangeHeader(range_header, &ranges)) {
if (ranges.size() == 1) {
byte_range_ = ranges[0];
} else {
// We don't support multiple range requests in one single URL request,
// because we need to do multipart encoding here.
// TODO(hclam): decide whether we want to support multiple range
// requests.
NotifyDone(URLRequestStatus(URLRequestStatus::FAILED,
ERR_REQUEST_RANGE_NOT_SATISFIABLE));
}
}
}
}
URLRequestFileJob::~URLRequestFileJob() {
#if defined(OS_WIN)
DCHECK(!async_resolver_);
#endif
}
void URLRequestFileJob::DidResolve(
bool exists, const base::PlatformFileInfo& file_info) {
#if defined(OS_WIN)
async_resolver_ = NULL;
#endif
// We may have been orphaned...
if (!request_)
return;
is_directory_ = file_info.is_directory;
int rv = OK;
// We use URLRequestFileJob to handle files as well as directories without
// trailing slash.
// If a directory does not exist, we return ERR_FILE_NOT_FOUND. Otherwise,
// we will append trailing slash and redirect to FileDirJob.
// A special case is "\" on Windows. We should resolve as invalid.
// However, Windows resolves "\" to "C:\", thus reports it as existent.
// So what happens is we append it with trailing slash and redirect it to
// FileDirJob where it is resolved as invalid.
if (!exists) {
rv = ERR_FILE_NOT_FOUND;
} else if (!is_directory_) {
// URL requests should not block on the disk!
// http://code.google.com/p/chromium/issues/detail?id=59849
base::ThreadRestrictions::ScopedAllowIO allow_io;
int flags = base::PLATFORM_FILE_OPEN |
base::PLATFORM_FILE_READ |
base::PLATFORM_FILE_ASYNC;
rv = stream_.Open(file_path_, flags);
}
if (rv != OK) {
NotifyDone(URLRequestStatus(URLRequestStatus::FAILED, rv));
return;
}
if (!byte_range_.ComputeBounds(file_info.size)) {
NotifyDone(URLRequestStatus(URLRequestStatus::FAILED,
ERR_REQUEST_RANGE_NOT_SATISFIABLE));
return;
}
remaining_bytes_ = byte_range_.last_byte_position() -
byte_range_.first_byte_position() + 1;
DCHECK_GE(remaining_bytes_, 0);
// URL requests should not block on the disk!
// http://code.google.com/p/chromium/issues/detail?id=59849
{
base::ThreadRestrictions::ScopedAllowIO allow_io;
// Do the seek at the beginning of the request.
if (remaining_bytes_ > 0 &&
byte_range_.first_byte_position() != 0 &&
byte_range_.first_byte_position() !=
stream_.Seek(FROM_BEGIN, byte_range_.first_byte_position())) {
NotifyDone(URLRequestStatus(URLRequestStatus::FAILED,
ERR_REQUEST_RANGE_NOT_SATISFIABLE));
return;
}
}
set_expected_content_size(remaining_bytes_);
NotifyHeadersComplete();
}
void URLRequestFileJob::DidRead(int result) {
if (result > 0) {
SetStatus(URLRequestStatus()); // Clear the IO_PENDING status
} else if (result == 0) {
NotifyDone(URLRequestStatus());
} else {
NotifyDone(URLRequestStatus(URLRequestStatus::FAILED, result));
}
remaining_bytes_ -= result;
DCHECK_GE(remaining_bytes_, 0);
NotifyReadComplete(result);
}
} // namespace net