net/http/partial_data.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 #include "net/http/partial_data.h"
   6
   7 #include "base/bind.h"
   8 #include "base/bind_helpers.h"
   9 #include "base/format_macros.h"
  10 #include "base/logging.h"
  11 #include "base/strings/string_number_conversions.h"
  12 #include "base/strings/string_util.h"
  13 #include "base/strings/stringprintf.h"
  14 #include "net/base/net_errors.h"
  15 #include "net/disk_cache/disk_cache.h"
  16 #include "net/http/http_response_headers.h"
  17 #include "net/http/http_util.h"
  18
  19 namespace net {
  20
  21 namespace {
  22
  23 // The headers that we have to process.
  24 const char kLengthHeader[] = "Content-Length";
  25 const char kRangeHeader[] = "Content-Range";
  26 const int kDataStream = 1;
  27
  28 }  // namespace
  29
  30 // A core object that can be detached from the Partialdata object at destruction
  31 // so that asynchronous operations cleanup can be performed.
  32 class PartialData::Core {
  33  public:
  34   // Build a new core object. Lifetime management is automatic.
  35   static Core* CreateCore(PartialData* owner) {
  36     return new Core(owner);
  37   }
  38
  39   // Wrapper for Entry::GetAvailableRange. If this method returns ERR_IO_PENDING
  40   // PartialData::GetAvailableRangeCompleted() will be invoked on the owner
  41   // object when finished (unless Cancel() is called first).
  42   int GetAvailableRange(disk_cache::Entry* entry, int64 offset, int len,
  43                         int64* start);
  44
  45   // Cancels a pending operation. It is a mistake to call this method if there
  46   // is no operation in progress; in fact, there will be no object to do so.
  47   void Cancel();
  48
  49  private:
  50   explicit Core(PartialData* owner);
  51   ~Core();
  52
  53   // Pending io completion routine.
  54   void OnIOComplete(int result);
  55
  56   PartialData* owner_;
  57   int64 start_;
  58
  59   DISALLOW_COPY_AND_ASSIGN(Core);
  60 };
  61
  62 PartialData::Core::Core(PartialData* owner)
  63     : owner_(owner), start_(0) {
  64   DCHECK(!owner_->core_);
  65   owner_->core_ = this;
  66 }
  67
  68 PartialData::Core::~Core() {
  69   if (owner_)
  70     owner_->core_ = NULL;
  71 }
  72
  73 void PartialData::Core::Cancel() {
  74   DCHECK(owner_);
  75   owner_ = NULL;
  76 }
  77
  78 int PartialData::Core::GetAvailableRange(disk_cache::Entry* entry, int64 offset,
  79                                          int len, int64* start) {
  80   int rv = entry->GetAvailableRange(
  81       offset, len, &start_, base::Bind(&PartialData::Core::OnIOComplete,
  82                                        base::Unretained(this)));
  83   if (rv != net::ERR_IO_PENDING) {
  84     // The callback will not be invoked. Lets cleanup.
  85     *start = start_;
  86     delete this;
  87   }
  88   return rv;
  89 }
  90
  91 void PartialData::Core::OnIOComplete(int result) {
  92   if (owner_)
  93     owner_->GetAvailableRangeCompleted(result, start_);
  94   delete this;
  95 }
  96
  97 // -----------------------------------------------------------------------------
  98
  99 PartialData::PartialData()
 100     : range_present_(false),
 101       final_range_(false),
 102       sparse_entry_(true),
 103       truncated_(false),
 104       initial_validation_(false),
 105       core_(NULL) {
 106 }
 107
 108 PartialData::~PartialData() {
 109   if (core_)
 110     core_->Cancel();
 111 }
 112
 113 bool PartialData::Init(const HttpRequestHeaders& headers) {
 114   std::string range_header;
 115   if (!headers.GetHeader(HttpRequestHeaders::kRange, &range_header))
 116     return false;
 117
 118   std::vector<HttpByteRange> ranges;
 119   if (!HttpUtil::ParseRangeHeader(range_header, &ranges) || ranges.size() != 1)
 120     return false;
 121
 122   // We can handle this range request.
 123   byte_range_ = ranges[0];
 124   if (!byte_range_.IsValid())
 125     return false;
 126
 127   resource_size_ = 0;
 128   current_range_start_ = byte_range_.first_byte_position();
 129
 130   DVLOG(1) << "Range start: " << current_range_start_ << " end: " <<
 131                byte_range_.last_byte_position();
 132   return true;
 133 }
 134
 135 void PartialData::SetHeaders(const HttpRequestHeaders& headers) {
 136   DCHECK(extra_headers_.IsEmpty());
 137   extra_headers_.CopyFrom(headers);
 138 }
 139
 140 void PartialData::RestoreHeaders(HttpRequestHeaders* headers) const {
 141   DCHECK(current_range_start_ >= 0 || byte_range_.IsSuffixByteRange());
 142   int64 end = byte_range_.IsSuffixByteRange() ?
 143               byte_range_.suffix_length() : byte_range_.last_byte_position();
 144
 145   headers->CopyFrom(extra_headers_);
 146   if (truncated_ || !byte_range_.IsValid())
 147     return;
 148
 149   if (current_range_start_ < 0) {
 150     headers->SetHeader(HttpRequestHeaders::kRange,
 151                        HttpByteRange::Suffix(end).GetHeaderValue());
 152   } else {
 153     headers->SetHeader(HttpRequestHeaders::kRange,
 154                        HttpByteRange::Bounded(
 155                            current_range_start_, end).GetHeaderValue());
 156   }
 157 }
 158
 159 int PartialData::ShouldValidateCache(disk_cache::Entry* entry,
 160                                      const CompletionCallback& callback) {
 161   DCHECK_GE(current_range_start_, 0);
 162
 163   // Scan the disk cache for the first cached portion within this range.
 164   int len = GetNextRangeLen();
 165   if (!len)
 166     return 0;
 167
 168   DVLOG(3) << "ShouldValidateCache len: " << len;
 169
 170   if (sparse_entry_) {
 171     DCHECK(callback_.is_null());
 172     Core* core = Core::CreateCore(this);
 173     cached_min_len_ = core->GetAvailableRange(entry, current_range_start_, len,
 174                                               &cached_start_);
 175
 176     if (cached_min_len_ == ERR_IO_PENDING) {
 177       callback_ = callback;
 178       return ERR_IO_PENDING;
 179     }
 180   } else if (!truncated_) {
 181     if (byte_range_.HasFirstBytePosition() &&
 182         byte_range_.first_byte_position() >= resource_size_) {
 183       // The caller should take care of this condition because we should have
 184       // failed IsRequestedRangeOK(), but it's better to be consistent here.
 185       len = 0;
 186     }
 187     cached_min_len_ = len;
 188     cached_start_ = current_range_start_;
 189   }
 190
 191   if (cached_min_len_ < 0)
 192     return cached_min_len_;
 193
 194   // Return a positive number to indicate success (versus error or finished).
 195   return 1;
 196 }
 197
 198 void PartialData::PrepareCacheValidation(disk_cache::Entry* entry,
 199                                          HttpRequestHeaders* headers) {
 200   DCHECK_GE(current_range_start_, 0);
 201   DCHECK_GE(cached_min_len_, 0);
 202
 203   int len = GetNextRangeLen();
 204   DCHECK_NE(0, len);
 205   range_present_ = false;
 206
 207   headers->CopyFrom(extra_headers_);
 208
 209   if (!cached_min_len_) {
 210     // We don't have anything else stored.
 211     final_range_ = true;
 212     cached_start_ =
 213         byte_range_.HasLastBytePosition() ? current_range_start_  + len : 0;
 214   }
 215
 216   if (current_range_start_ == cached_start_) {
 217     // The data lives in the cache.
 218     range_present_ = true;
 219     if (len == cached_min_len_)
 220       final_range_ = true;
 221     headers->SetHeader(
 222         HttpRequestHeaders::kRange,
 223         net::HttpByteRange::Bounded(
 224             current_range_start_,
 225             cached_start_ + cached_min_len_ - 1).GetHeaderValue());
 226   } else {
 227     // This range is not in the cache.
 228     headers->SetHeader(
 229         HttpRequestHeaders::kRange,
 230         net::HttpByteRange::Bounded(
 231             current_range_start_, cached_start_ - 1).GetHeaderValue());
 232   }
 233 }
 234
 235 bool PartialData::IsCurrentRangeCached() const {
 236   return range_present_;
 237 }
 238
 239 bool PartialData::IsLastRange() const {
 240   return final_range_;
 241 }
 242
 243 bool PartialData::UpdateFromStoredHeaders(const HttpResponseHeaders* headers,
 244                                           disk_cache::Entry* entry,
 245                                           bool truncated) {
 246   resource_size_ = 0;
 247   if (truncated) {
 248     DCHECK_EQ(headers->response_code(), 200);
 249     // We don't have the real length and the user may be trying to create a
 250     // sparse entry so let's not write to this entry.
 251     if (byte_range_.IsValid())
 252       return false;
 253
 254     if (!headers->HasStrongValidators())
 255       return false;
 256
 257     // Now we avoid resume if there is no content length, but that was not
 258     // always the case so double check here.
 259     int64 total_length = headers->GetContentLength();
 260     if (total_length <= 0)
 261       return false;
 262
 263     truncated_ = true;
 264     initial_validation_ = true;
 265     sparse_entry_ = false;
 266     int current_len = entry->GetDataSize(kDataStream);
 267     byte_range_.set_first_byte_position(current_len);
 268     resource_size_ = total_length;
 269     current_range_start_ = current_len;
 270     cached_min_len_ = current_len;
 271     cached_start_ = current_len + 1;
 272     return true;
 273   }
 274
 275   if (headers->response_code() != 206) {
 276     DCHECK(byte_range_.IsValid());
 277     sparse_entry_ = false;
 278     resource_size_ = entry->GetDataSize(kDataStream);
 279     DVLOG(2) << "UpdateFromStoredHeaders size: " << resource_size_;
 280     return true;
 281   }
 282
 283   if (!headers->HasStrongValidators())
 284     return false;
 285
 286   int64 length_value = headers->GetContentLength();
 287   if (length_value <= 0)
 288     return false;  // We must have stored the resource length.
 289
 290   resource_size_ = length_value;
 291
 292   // Make sure that this is really a sparse entry.
 293   return entry->CouldBeSparse();
 294 }
 295
 296 void PartialData::SetRangeToStartDownload() {
 297   DCHECK(truncated_);
 298   DCHECK(!sparse_entry_);
 299   current_range_start_ = 0;
 300   cached_start_ = 0;
 301   initial_validation_ = false;
 302 }
 303
 304 bool PartialData::IsRequestedRangeOK() {
 305   if (byte_range_.IsValid()) {
 306     if (!byte_range_.ComputeBounds(resource_size_))
 307       return false;
 308     if (truncated_)
 309       return true;
 310
 311     if (current_range_start_ < 0)
 312       current_range_start_ = byte_range_.first_byte_position();
 313   } else {
 314     // This is not a range request but we have partial data stored.
 315     current_range_start_ = 0;
 316     byte_range_.set_last_byte_position(resource_size_ - 1);
 317   }
 318
 319   bool rv = current_range_start_ >= 0;
 320   if (!rv)
 321     current_range_start_ = 0;
 322
 323   return rv;
 324 }
 325
 326 bool PartialData::ResponseHeadersOK(const HttpResponseHeaders* headers) {
 327   if (headers->response_code() == 304) {
 328     if (!byte_range_.IsValid() || truncated_)
 329       return true;
 330
 331     // We must have a complete range here.
 332     return byte_range_.HasFirstBytePosition() &&
 333         byte_range_.HasLastBytePosition();
 334   }
 335
 336   int64 start, end, total_length;
 337   if (!headers->GetContentRange(&start, &end, &total_length))
 338     return false;
 339   if (total_length <= 0)
 340     return false;
 341
 342   DCHECK_EQ(headers->response_code(), 206);
 343
 344   // A server should return a valid content length with a 206 (per the standard)
 345   // but relax the requirement because some servers don't do that.
 346   int64 content_length = headers->GetContentLength();
 347   if (content_length > 0 && content_length != end - start + 1)
 348     return false;
 349
 350   if (!resource_size_) {
 351     // First response. Update our values with the ones provided by the server.
 352     resource_size_ = total_length;
 353     if (!byte_range_.HasFirstBytePosition()) {
 354       byte_range_.set_first_byte_position(start);
 355       current_range_start_ = start;
 356     }
 357     if (!byte_range_.HasLastBytePosition())
 358       byte_range_.set_last_byte_position(end);
 359   } else if (resource_size_ != total_length) {
 360     return false;
 361   }
 362
 363   if (truncated_) {
 364     if (!byte_range_.HasLastBytePosition())
 365       byte_range_.set_last_byte_position(end);
 366   }
 367
 368   if (start != current_range_start_)
 369     return false;
 370
 371   if (byte_range_.IsValid() && end > byte_range_.last_byte_position())
 372     return false;
 373
 374   return true;
 375 }
 376
 377 // We are making multiple requests to complete the range requested by the user.
 378 // Just assume that everything is fine and say that we are returning what was
 379 // requested.
 380 void PartialData::FixResponseHeaders(HttpResponseHeaders* headers,
 381                                      bool success) {
 382   if (truncated_)
 383     return;
 384
 385   if (byte_range_.IsValid() && success) {
 386     headers->UpdateWithNewRange(byte_range_, resource_size_, !sparse_entry_);
 387     return;
 388   }
 389
 390   headers->RemoveHeader(kLengthHeader);
 391   headers->RemoveHeader(kRangeHeader);
 392
 393   if (byte_range_.IsValid()) {
 394     headers->ReplaceStatusLine("HTTP/1.1 416 Requested Range Not Satisfiable");
 395     headers->AddHeader(base::StringPrintf("%s: bytes 0-0/%" PRId64,
 396                                           kRangeHeader, resource_size_));
 397     headers->AddHeader(base::StringPrintf("%s: 0", kLengthHeader));
 398   } else {
 399     // TODO(rvargas): Is it safe to change the protocol version?
 400     headers->ReplaceStatusLine("HTTP/1.1 200 OK");
 401     DCHECK_NE(resource_size_, 0);
 402     headers->AddHeader(base::StringPrintf("%s: %" PRId64, kLengthHeader,
 403                                           resource_size_));
 404   }
 405 }
 406
 407 void PartialData::FixContentLength(HttpResponseHeaders* headers) {
 408   headers->RemoveHeader(kLengthHeader);
 409   headers->AddHeader(base::StringPrintf("%s: %" PRId64, kLengthHeader,
 410                                         resource_size_));
 411 }
 412
 413 int PartialData::CacheRead(
 414     disk_cache::Entry* entry, IOBuffer* data, int data_len,
 415     const net::CompletionCallback& callback) {
 416   int read_len = std::min(data_len, cached_min_len_);
 417   if (!read_len)
 418     return 0;
 419
 420   int rv = 0;
 421   if (sparse_entry_) {
 422     rv = entry->ReadSparseData(current_range_start_, data, read_len,
 423                                callback);
 424   } else {
 425     if (current_range_start_ > kint32max)
 426       return ERR_INVALID_ARGUMENT;
 427
 428     rv = entry->ReadData(kDataStream, static_cast<int>(current_range_start_),
 429                          data, read_len, callback);
 430   }
 431   return rv;
 432 }
 433
 434 int PartialData::CacheWrite(
 435     disk_cache::Entry* entry, IOBuffer* data, int data_len,
 436     const net::CompletionCallback& callback) {
 437   DVLOG(3) << "To write: " << data_len;
 438   if (sparse_entry_) {
 439     return entry->WriteSparseData(
 440         current_range_start_, data, data_len, callback);
 441   } else  {
 442     if (current_range_start_ > kint32max)
 443       return ERR_INVALID_ARGUMENT;
 444
 445     return entry->WriteData(kDataStream, static_cast<int>(current_range_start_),
 446                             data, data_len, callback, true);
 447   }
 448 }
 449
 450 void PartialData::OnCacheReadCompleted(int result) {
 451   DVLOG(3) << "Read: " << result;
 452   if (result > 0) {
 453     current_range_start_ += result;
 454     cached_min_len_ -= result;
 455     DCHECK_GE(cached_min_len_, 0);
 456   }
 457 }
 458
 459 void PartialData::OnNetworkReadCompleted(int result) {
 460   if (result > 0)
 461     current_range_start_ += result;
 462 }
 463
 464 int PartialData::GetNextRangeLen() {
 465   int64 range_len =
 466       byte_range_.HasLastBytePosition() ?
 467       byte_range_.last_byte_position() - current_range_start_ + 1 :
 468       kint32max;
 469   if (range_len > kint32max)
 470     range_len = kint32max;
 471   return static_cast<int32>(range_len);
 472 }
 473
 474 void PartialData::GetAvailableRangeCompleted(int result, int64 start) {
 475   DCHECK(!callback_.is_null());
 476   DCHECK_NE(ERR_IO_PENDING, result);
 477
 478   cached_start_ = start;
 479   cached_min_len_ = result;
 480   if (result >= 0)
 481     result = 1;  // Return success, go ahead and validate the entry.
 482
 483   CompletionCallback cb = callback_;
 484   callback_.Reset();
 485   cb.Run(result);
 486 }
 487
 488 }  // namespace net