src/net/url_request/url_request_file_job.cc

   1 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 // For loading files, we make use of overlapped i/o to ensure that reading from
   6 // the filesystem (e.g., a network filesystem) does not block the calling
   7 // thread.  An alternative approach would be to use a background thread or pool
   8 // of threads, but it seems better to leverage the operating system's ability
   9 // to do background file reads for us.
  10 //
  11 // Since overlapped reads require a 'static' buffer for the duration of the
  12 // asynchronous read, the URLRequestFileJob keeps a buffer as a member var.  In
  13 // URLRequestFileJob::Read, data is simply copied from the object's buffer into
  14 // the given buffer.  If there is no data to copy, the URLRequestFileJob
  15 // attempts to read more from the file to fill its buffer.  If reading from the
  16 // file does not complete synchronously, then the URLRequestFileJob waits for a
  17 // signal from the OS that the overlapped read has completed.  It does so by
  18 // leveraging the MessageLoop::WatchObject API.
  19
  20 #include "net/url_request/url_request_file_job.h"
  21
  22 #include "base/bind.h"
  23 #include "base/compiler_specific.h"
  24 #include "base/files/file_util.h"
  25 #include "base/message_loop/message_loop.h"
  26 #include "base/strings/string_util.h"
  27 #include "base/synchronization/lock.h"
  28 #include "base/task_runner.h"
  29 #include "base/threading/thread_restrictions.h"
  30 #include "build/build_config.h"
  31 #include "net/base/file_stream.h"
  32 #include "net/base/filename_util.h"
  33 #include "net/base/io_buffer.h"
  34 #include "net/base/load_flags.h"
  35 #include "net/base/mime_util.h"
  36 #include "net/base/net_errors.h"
  37 #include "net/filter/filter.h"
  38 #include "net/http/http_util.h"
  39 #include "net/url_request/url_request_error_job.h"
  40 #include "net/url_request/url_request_file_dir_job.h"
  41 #include "url/gurl.h"
  42
  43 #if defined(OS_WIN)
  44 #include "base/win/shortcut.h"
  45 #endif
  46
  47 namespace net {
  48
  49 URLRequestFileJob::FileMetaInfo::FileMetaInfo()
  50     : file_size(0),
  51       mime_type_result(false),
  52       file_exists(false),
  53       is_directory(false) {
  54 }
  55
  56 URLRequestFileJob::URLRequestFileJob(
  57     URLRequest* request,
  58     NetworkDelegate* network_delegate,
  59     const base::FilePath& file_path,
  60     const scoped_refptr<base::TaskRunner>& file_task_runner)
  61     : URLRequestJob(request, network_delegate),
  62       file_path_(file_path),
  63       stream_(new FileStream(file_task_runner)),
  64       file_task_runner_(file_task_runner),
  65       remaining_bytes_(0),
  66       weak_ptr_factory_(this) {}
  67
  68 void URLRequestFileJob::Start() {
  69   FileMetaInfo* meta_info = new FileMetaInfo();
  70   file_task_runner_->PostTaskAndReply(
  71       FROM_HERE,
  72       base::Bind(&URLRequestFileJob::FetchMetaInfo, file_path_,
  73                  base::Unretained(meta_info)),
  74       base::Bind(&URLRequestFileJob::DidFetchMetaInfo,
  75                  weak_ptr_factory_.GetWeakPtr(),
  76                  base::Owned(meta_info)));
  77 }
  78
  79 void URLRequestFileJob::Kill() {
  80   stream_.reset();
  81   weak_ptr_factory_.InvalidateWeakPtrs();
  82
  83   URLRequestJob::Kill();
  84 }
  85
  86 bool URLRequestFileJob::ReadRawData(IOBuffer* dest,
  87                                     int dest_size,
  88                                     int* bytes_read) {
  89   DCHECK_NE(dest_size, 0);
  90   DCHECK(bytes_read);
  91   DCHECK_GE(remaining_bytes_, 0);
  92
  93   if (remaining_bytes_ < dest_size)
  94     dest_size = static_cast<int>(remaining_bytes_);
  95
  96   // If we should copy zero bytes because |remaining_bytes_| is zero, short
  97   // circuit here.
  98   if (!dest_size) {
  99     *bytes_read = 0;
 100     return true;
 101   }
 102
 103   int rv = stream_->Read(dest,
 104                          dest_size,
 105                          base::Bind(&URLRequestFileJob::DidRead,
 106                                     weak_ptr_factory_.GetWeakPtr(),
 107                                     make_scoped_refptr(dest)));
 108   if (rv >= 0) {
 109     // Data is immediately available.
 110     *bytes_read = rv;
 111     remaining_bytes_ -= rv;
 112     DCHECK_GE(remaining_bytes_, 0);
 113     return true;
 114   }
 115
 116   // Otherwise, a read error occured.  We may just need to wait...
 117   if (rv == ERR_IO_PENDING) {
 118     SetStatus(URLRequestStatus(URLRequestStatus::IO_PENDING, 0));
 119   } else {
 120     NotifyDone(URLRequestStatus(URLRequestStatus::FAILED, rv));
 121   }
 122   return false;
 123 }
 124
 125 bool URLRequestFileJob::IsRedirectResponse(GURL* location,
 126                                            int* http_status_code) {
 127   if (meta_info_.is_directory) {
 128     // This happens when we discovered the file is a directory, so needs a
 129     // slash at the end of the path.
 130     std::string new_path = request_->url().path();
 131     new_path.push_back('/');
 132     GURL::Replacements replacements;
 133     replacements.SetPathStr(new_path);
 134
 135     *location = request_->url().ReplaceComponents(replacements);
 136     *http_status_code = 301;  // simulate a permanent redirect
 137     return true;
 138   }
 139
 140 #if defined(OS_WIN)
 141   // Follow a Windows shortcut.
 142   // We just resolve .lnk file, ignore others.
 143   if (!LowerCaseEqualsASCII(file_path_.Extension(), ".lnk"))
 144     return false;
 145
 146   base::FilePath new_path = file_path_;
 147   bool resolved;
 148   resolved = base::win::ResolveShortcut(new_path, &new_path, NULL);
 149
 150   // If shortcut is not resolved succesfully, do not redirect.
 151   if (!resolved)
 152     return false;
 153
 154   *location = FilePathToFileURL(new_path);
 155   *http_status_code = 301;
 156   return true;
 157 #else
 158   return false;
 159 #endif
 160 }
 161
 162 Filter* URLRequestFileJob::SetupFilter() const {
 163   // Bug 9936 - .svgz files needs to be decompressed.
 164   return LowerCaseEqualsASCII(file_path_.Extension(), ".svgz")
 165       ? Filter::GZipFactory() : NULL;
 166 }
 167
 168 bool URLRequestFileJob::GetMimeType(std::string* mime_type) const {
 169   DCHECK(request_);
 170   if (meta_info_.mime_type_result) {
 171     *mime_type = meta_info_.mime_type;
 172     return true;
 173   }
 174   return false;
 175 }
 176
 177 void URLRequestFileJob::SetExtraRequestHeaders(
 178     const HttpRequestHeaders& headers) {
 179   std::string range_header;
 180   if (headers.GetHeader(HttpRequestHeaders::kRange, &range_header)) {
 181     // We only care about "Range" header here.
 182     std::vector<HttpByteRange> ranges;
 183     if (HttpUtil::ParseRangeHeader(range_header, &ranges)) {
 184       if (ranges.size() == 1) {
 185         byte_range_ = ranges[0];
 186       } else {
 187         // We don't support multiple range requests in one single URL request,
 188         // because we need to do multipart encoding here.
 189         // TODO(hclam): decide whether we want to support multiple range
 190         // requests.
 191         NotifyDone(URLRequestStatus(URLRequestStatus::FAILED,
 192                                     ERR_REQUEST_RANGE_NOT_SATISFIABLE));
 193       }
 194     }
 195   }
 196 }
 197
 198 void URLRequestFileJob::OnSeekComplete(int64 result) {
 199 }
 200
 201 void URLRequestFileJob::OnReadComplete(net::IOBuffer* buf, int result) {
 202 }
 203
 204 URLRequestFileJob::~URLRequestFileJob() {
 205 }
 206
 207 void URLRequestFileJob::FetchMetaInfo(const base::FilePath& file_path,
 208                                       FileMetaInfo* meta_info) {
 209   base::File::Info file_info;
 210   meta_info->file_exists = base::GetFileInfo(file_path, &file_info);
 211   if (meta_info->file_exists) {
 212     meta_info->file_size = file_info.size;
 213     meta_info->is_directory = file_info.is_directory;
 214   }
 215   // On Windows GetMimeTypeFromFile() goes to the registry. Thus it should be
 216   // done in WorkerPool.
 217   meta_info->mime_type_result = GetMimeTypeFromFile(file_path,
 218                                                     &meta_info->mime_type);
 219 }
 220
 221 void URLRequestFileJob::DidFetchMetaInfo(const FileMetaInfo* meta_info) {
 222   meta_info_ = *meta_info;
 223
 224   // We use URLRequestFileJob to handle files as well as directories without
 225   // trailing slash.
 226   // If a directory does not exist, we return ERR_FILE_NOT_FOUND. Otherwise,
 227   // we will append trailing slash and redirect to FileDirJob.
 228   // A special case is "\" on Windows. We should resolve as invalid.
 229   // However, Windows resolves "\" to "C:\", thus reports it as existent.
 230   // So what happens is we append it with trailing slash and redirect it to
 231   // FileDirJob where it is resolved as invalid.
 232   if (!meta_info_.file_exists) {
 233     DidOpen(ERR_FILE_NOT_FOUND);
 234     return;
 235   }
 236   if (meta_info_.is_directory) {
 237     DidOpen(OK);
 238     return;
 239   }
 240
 241   int flags = base::File::FLAG_OPEN |
 242               base::File::FLAG_READ |
 243               base::File::FLAG_ASYNC;
 244   int rv = stream_->Open(file_path_, flags,
 245                          base::Bind(&URLRequestFileJob::DidOpen,
 246                                     weak_ptr_factory_.GetWeakPtr()));
 247   if (rv != ERR_IO_PENDING)
 248     DidOpen(rv);
 249 }
 250
 251 void URLRequestFileJob::DidOpen(int result) {
 252   if (result != OK) {
 253     NotifyDone(URLRequestStatus(URLRequestStatus::FAILED, result));
 254     return;
 255   }
 256
 257   if (!byte_range_.ComputeBounds(meta_info_.file_size)) {
 258     NotifyDone(URLRequestStatus(URLRequestStatus::FAILED,
 259                ERR_REQUEST_RANGE_NOT_SATISFIABLE));
 260     return;
 261   }
 262
 263   remaining_bytes_ = byte_range_.last_byte_position() -
 264                      byte_range_.first_byte_position() + 1;
 265   DCHECK_GE(remaining_bytes_, 0);
 266
 267   if (remaining_bytes_ > 0 && byte_range_.first_byte_position() != 0) {
 268     int rv = stream_->Seek(base::File::FROM_BEGIN,
 269                            byte_range_.first_byte_position(),
 270                            base::Bind(&URLRequestFileJob::DidSeek,
 271                                       weak_ptr_factory_.GetWeakPtr()));
 272     if (rv != ERR_IO_PENDING) {
 273       // stream_->Seek() failed, so pass an intentionally erroneous value
 274       // into DidSeek().
 275       DidSeek(-1);
 276     }
 277   } else {
 278     // We didn't need to call stream_->Seek() at all, so we pass to DidSeek()
 279     // the value that would mean seek success. This way we skip the code
 280     // handling seek failure.
 281     DidSeek(byte_range_.first_byte_position());
 282   }
 283 }
 284
 285 void URLRequestFileJob::DidSeek(int64 result) {
 286   OnSeekComplete(result);
 287   if (result != byte_range_.first_byte_position()) {
 288     NotifyDone(URLRequestStatus(URLRequestStatus::FAILED,
 289                                 ERR_REQUEST_RANGE_NOT_SATISFIABLE));
 290     return;
 291   }
 292
 293   set_expected_content_size(remaining_bytes_);
 294   NotifyHeadersComplete();
 295 }
 296
 297 void URLRequestFileJob::DidRead(scoped_refptr<net::IOBuffer> buf, int result) {
 298   if (result > 0) {
 299     SetStatus(URLRequestStatus());  // Clear the IO_PENDING status
 300     remaining_bytes_ -= result;
 301     DCHECK_GE(remaining_bytes_, 0);
 302   }
 303
 304   OnReadComplete(buf.get(), result);
 305   buf = NULL;
 306
 307   if (result == 0) {
 308     NotifyDone(URLRequestStatus());
 309   } else if (result < 0) {
 310     NotifyDone(URLRequestStatus(URLRequestStatus::FAILED, result));
 311   }
 312
 313   NotifyReadComplete(result);
 314 }
 315
 316 }  // namespace net