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/profiler/scoped_tracker.h"
  12 #include "base/strings/string_number_conversions.h"
  13 #include "base/strings/string_util.h"
  14 #include "base/strings/stringprintf.h"
  15 #include "net/base/net_errors.h"
  16 #include "net/disk_cache/disk_cache.h"
  17 #include "net/http/http_response_headers.h"
  18 #include "net/http/http_util.h"
  19
  20 namespace net {
  21
  22 namespace {
  23
  24 // The headers that we have to process.
  25 const char kLengthHeader[] = "Content-Length";
  26 const char kRangeHeader[] = "Content-Range";
  27 const int kDataStream = 1;
  28
  29 }  // namespace
  30
  31 // A core object that can be detached from the Partialdata object at destruction
  32 // so that asynchronous operations cleanup can be performed.
  33 class PartialData::Core {
  34  public:
  35   // Build a new core object. Lifetime management is automatic.
  36   static Core* CreateCore(PartialData* owner) {
  37     return new Core(owner);
  38   }
  39
  40   // Wrapper for Entry::GetAvailableRange. If this method returns ERR_IO_PENDING
  41   // PartialData::GetAvailableRangeCompleted() will be invoked on the owner
  42   // object when finished (unless Cancel() is called first).
  43   int GetAvailableRange(disk_cache::Entry* entry, int64 offset, int len,
  44                         int64* start);
  45
  46   // Cancels a pending operation. It is a mistake to call this method if there
  47   // is no operation in progress; in fact, there will be no object to do so.
  48   void Cancel();
  49
  50  private:
  51   explicit Core(PartialData* owner);
  52   ~Core();
  53
  54   // Pending io completion routine.
  55   void OnIOComplete(int result);
  56
  57   PartialData* owner_;
  58   int64 start_;
  59
  60   DISALLOW_COPY_AND_ASSIGN(Core);
  61 };
  62
  63 PartialData::Core::Core(PartialData* owner)
  64     : owner_(owner), start_(0) {
  65   DCHECK(!owner_->core_);
  66   owner_->core_ = this;
  67 }
  68
  69 PartialData::Core::~Core() {
  70   if (owner_)
  71     owner_->core_ = NULL;
  72 }
  73
  74 void PartialData::Core::Cancel() {
  75   DCHECK(owner_);
  76   owner_ = NULL;
  77 }
  78
  79 int PartialData::Core::GetAvailableRange(disk_cache::Entry* entry, int64 offset,
  80                                          int len, int64* start) {
  81   int rv = entry->GetAvailableRange(
  82       offset, len, &start_, base::Bind(&PartialData::Core::OnIOComplete,
  83                                        base::Unretained(this)));
  84   if (rv != net::ERR_IO_PENDING) {
  85     // The callback will not be invoked. Lets cleanup.
  86     *start = start_;
  87     delete this;
  88   }
  89   return rv;
  90 }
  91
  92 void PartialData::Core::OnIOComplete(int result) {
  93   // TODO(vadimt): Remove ScopedTracker below once crbug.com/422516 is fixed.
  94   tracked_objects::ScopedTracker tracking_profile(
  95       FROM_HERE_WITH_EXPLICIT_FUNCTION(
  96           "422516 PartialData::Core::OnIOComplete"));
  97
  98   if (owner_)
  99     owner_->GetAvailableRangeCompleted(result, start_);
 100   delete this;
 101 }
 102
 103 // -----------------------------------------------------------------------------
 104
 105 PartialData::PartialData()
 106     : range_present_(false),
 107       final_range_(false),
 108       sparse_entry_(true),
 109       truncated_(false),
 110       initial_validation_(false),
 111       core_(NULL) {
 112 }
 113
 114 PartialData::~PartialData() {
 115   if (core_)
 116     core_->Cancel();
 117 }
 118
 119 bool PartialData::Init(const HttpRequestHeaders& headers) {
 120   std::string range_header;
 121   if (!headers.GetHeader(HttpRequestHeaders::kRange, &range_header))
 122     return false;
 123
 124   std::vector<HttpByteRange> ranges;
 125   if (!HttpUtil::ParseRangeHeader(range_header, &ranges) || ranges.size() != 1)
 126     return false;
 127
 128   // We can handle this range request.
 129   byte_range_ = ranges[0];
 130   if (!byte_range_.IsValid())
 131     return false;
 132
 133   resource_size_ = 0;
 134   current_range_start_ = byte_range_.first_byte_position();
 135
 136   DVLOG(1) << "Range start: " << current_range_start_ << " end: " <<
 137                byte_range_.last_byte_position();
 138   return true;
 139 }
 140
 141 void PartialData::SetHeaders(const HttpRequestHeaders& headers) {
 142   DCHECK(extra_headers_.IsEmpty());
 143   extra_headers_.CopyFrom(headers);
 144 }
 145
 146 void PartialData::RestoreHeaders(HttpRequestHeaders* headers) const {
 147   DCHECK(current_range_start_ >= 0 || byte_range_.IsSuffixByteRange());
 148   int64 end = byte_range_.IsSuffixByteRange() ?
 149               byte_range_.suffix_length() : byte_range_.last_byte_position();
 150
 151   headers->CopyFrom(extra_headers_);
 152   if (truncated_ || !byte_range_.IsValid())
 153     return;
 154
 155   if (current_range_start_ < 0) {
 156     headers->SetHeader(HttpRequestHeaders::kRange,
 157                        HttpByteRange::Suffix(end).GetHeaderValue());
 158   } else {
 159     headers->SetHeader(HttpRequestHeaders::kRange,
 160                        HttpByteRange::Bounded(
 161                            current_range_start_, end).GetHeaderValue());
 162   }
 163 }
 164
 165 int PartialData::ShouldValidateCache(disk_cache::Entry* entry,
 166                                      const CompletionCallback& callback) {
 167   DCHECK_GE(current_range_start_, 0);
 168
 169   // Scan the disk cache for the first cached portion within this range.
 170   int len = GetNextRangeLen();
 171   if (!len)
 172     return 0;
 173
 174   DVLOG(3) << "ShouldValidateCache len: " << len;
 175
 176   if (sparse_entry_) {
 177     DCHECK(callback_.is_null());
 178     Core* core = Core::CreateCore(this);
 179     cached_min_len_ = core->GetAvailableRange(entry, current_range_start_, len,
 180                                               &cached_start_);
 181
 182     if (cached_min_len_ == ERR_IO_PENDING) {
 183       callback_ = callback;
 184       return ERR_IO_PENDING;
 185     }
 186   } else if (!truncated_) {
 187     if (byte_range_.HasFirstBytePosition() &&
 188         byte_range_.first_byte_position() >= resource_size_) {
 189       // The caller should take care of this condition because we should have
 190       // failed IsRequestedRangeOK(), but it's better to be consistent here.
 191       len = 0;
 192     }
 193     cached_min_len_ = len;
 194     cached_start_ = current_range_start_;
 195   }
 196
 197   if (cached_min_len_ < 0)
 198     return cached_min_len_;
 199
 200   // Return a positive number to indicate success (versus error or finished).
 201   return 1;
 202 }
 203
 204 void PartialData::PrepareCacheValidation(disk_cache::Entry* entry,
 205                                          HttpRequestHeaders* headers) {
 206   DCHECK_GE(current_range_start_, 0);
 207   DCHECK_GE(cached_min_len_, 0);
 208
 209   int len = GetNextRangeLen();
 210   DCHECK_NE(0, len);
 211   range_present_ = false;
 212
 213   headers->CopyFrom(extra_headers_);
 214
 215   if (!cached_min_len_) {
 216     // We don't have anything else stored.
 217     final_range_ = true;
 218     cached_start_ =
 219         byte_range_.HasLastBytePosition() ? current_range_start_  + len : 0;
 220   }
 221
 222   if (current_range_start_ == cached_start_) {
 223     // The data lives in the cache.
 224     range_present_ = true;
 225     if (len == cached_min_len_)
 226       final_range_ = true;
 227     headers->SetHeader(
 228         HttpRequestHeaders::kRange,
 229         net::HttpByteRange::Bounded(
 230             current_range_start_,
 231             cached_start_ + cached_min_len_ - 1).GetHeaderValue());
 232   } else {
 233     // This range is not in the cache.
 234     headers->SetHeader(
 235         HttpRequestHeaders::kRange,
 236         net::HttpByteRange::Bounded(
 237             current_range_start_, cached_start_ - 1).GetHeaderValue());
 238   }
 239 }
 240
 241 bool PartialData::IsCurrentRangeCached() const {
 242   return range_present_;
 243 }
 244
 245 bool PartialData::IsLastRange() const {
 246   return final_range_;
 247 }
 248
 249 bool PartialData::UpdateFromStoredHeaders(const HttpResponseHeaders* headers,
 250                                           disk_cache::Entry* entry,
 251                                           bool truncated) {
 252   resource_size_ = 0;
 253   if (truncated) {
 254     DCHECK_EQ(headers->response_code(), 200);
 255     // We don't have the real length and the user may be trying to create a
 256     // sparse entry so let's not write to this entry.
 257     if (byte_range_.IsValid())
 258       return false;
 259
 260     if (!headers->HasStrongValidators())
 261       return false;
 262
 263     // Now we avoid resume if there is no content length, but that was not
 264     // always the case so double check here.
 265     int64 total_length = headers->GetContentLength();
 266     if (total_length <= 0)
 267       return false;
 268
 269     truncated_ = true;
 270     initial_validation_ = true;
 271     sparse_entry_ = false;
 272     int current_len = entry->GetDataSize(kDataStream);
 273     byte_range_.set_first_byte_position(current_len);
 274     resource_size_ = total_length;
 275     current_range_start_ = current_len;
 276     cached_min_len_ = current_len;
 277     cached_start_ = current_len + 1;
 278     return true;
 279   }
 280
 281   if (headers->response_code() != 206) {
 282     DCHECK(byte_range_.IsValid());
 283     sparse_entry_ = false;
 284     resource_size_ = entry->GetDataSize(kDataStream);
 285     DVLOG(2) << "UpdateFromStoredHeaders size: " << resource_size_;
 286     return true;
 287   }
 288
 289   int64 length_value = headers->GetContentLength();
 290   if (length_value <= 0)
 291     return false;  // We must have stored the resource length.
 292
 293   resource_size_ = length_value;
 294
 295   // Make sure that this is really a sparse entry.
 296   return entry->CouldBeSparse();
 297 }
 298
 299 void PartialData::SetRangeToStartDownload() {
 300   DCHECK(truncated_);
 301   DCHECK(!sparse_entry_);
 302   current_range_start_ = 0;
 303   cached_start_ = 0;
 304   initial_validation_ = false;
 305 }
 306
 307 bool PartialData::IsRequestedRangeOK() {
 308   if (byte_range_.IsValid()) {
 309     if (!byte_range_.ComputeBounds(resource_size_))
 310       return false;
 311     if (truncated_)
 312       return true;
 313
 314     if (current_range_start_ < 0)
 315       current_range_start_ = byte_range_.first_byte_position();
 316   } else {
 317     // This is not a range request but we have partial data stored.
 318     current_range_start_ = 0;
 319     byte_range_.set_last_byte_position(resource_size_ - 1);
 320   }
 321
 322   bool rv = current_range_start_ >= 0;
 323   if (!rv)
 324     current_range_start_ = 0;
 325
 326   return rv;
 327 }
 328
 329 bool PartialData::ResponseHeadersOK(const HttpResponseHeaders* headers) {
 330   if (headers->response_code() == 304) {
 331     if (!byte_range_.IsValid() || truncated_)
 332       return true;
 333
 334     // We must have a complete range here.
 335     return byte_range_.HasFirstBytePosition() &&
 336         byte_range_.HasLastBytePosition();
 337   }
 338
 339   int64 start, end, total_length;
 340   if (!headers->GetContentRange(&start, &end, &total_length))
 341     return false;
 342   if (total_length <= 0)
 343     return false;
 344
 345   DCHECK_EQ(headers->response_code(), 206);
 346
 347   // A server should return a valid content length with a 206 (per the standard)
 348   // but relax the requirement because some servers don't do that.
 349   int64 content_length = headers->GetContentLength();
 350   if (content_length > 0 && content_length != end - start + 1)
 351     return false;
 352
 353   if (!resource_size_) {
 354     // First response. Update our values with the ones provided by the server.
 355     resource_size_ = total_length;
 356     if (!byte_range_.HasFirstBytePosition()) {
 357       byte_range_.set_first_byte_position(start);
 358       current_range_start_ = start;
 359     }
 360     if (!byte_range_.HasLastBytePosition())
 361       byte_range_.set_last_byte_position(end);
 362   } else if (resource_size_ != total_length) {
 363     return false;
 364   }
 365
 366   if (truncated_) {
 367     if (!byte_range_.HasLastBytePosition())
 368       byte_range_.set_last_byte_position(end);
 369   }
 370
 371   if (start != current_range_start_)
 372     return false;
 373
 374   if (byte_range_.IsValid() && end > byte_range_.last_byte_position())
 375     return false;
 376
 377   return true;
 378 }
 379
 380 // We are making multiple requests to complete the range requested by the user.
 381 // Just assume that everything is fine and say that we are returning what was
 382 // requested.
 383 void PartialData::FixResponseHeaders(HttpResponseHeaders* headers,
 384                                      bool success) {
 385   if (truncated_)
 386     return;
 387
 388   if (byte_range_.IsValid() && success) {
 389     headers->UpdateWithNewRange(byte_range_, resource_size_, !sparse_entry_);
 390     return;
 391   }
 392
 393   headers->RemoveHeader(kLengthHeader);
 394   headers->RemoveHeader(kRangeHeader);
 395
 396   if (byte_range_.IsValid()) {
 397     headers->ReplaceStatusLine("HTTP/1.1 416 Requested Range Not Satisfiable");
 398     headers->AddHeader(base::StringPrintf("%s: bytes 0-0/%" PRId64,
 399                                           kRangeHeader, resource_size_));
 400     headers->AddHeader(base::StringPrintf("%s: 0", kLengthHeader));
 401   } else {
 402     // TODO(rvargas): Is it safe to change the protocol version?
 403     headers->ReplaceStatusLine("HTTP/1.1 200 OK");
 404     DCHECK_NE(resource_size_, 0);
 405     headers->AddHeader(base::StringPrintf("%s: %" PRId64, kLengthHeader,
 406                                           resource_size_));
 407   }
 408 }
 409
 410 void PartialData::FixContentLength(HttpResponseHeaders* headers) {
 411   headers->RemoveHeader(kLengthHeader);
 412   headers->AddHeader(base::StringPrintf("%s: %" PRId64, kLengthHeader,
 413                                         resource_size_));
 414 }
 415
 416 int PartialData::CacheRead(
 417     disk_cache::Entry* entry, IOBuffer* data, int data_len,
 418     const net::CompletionCallback& callback) {
 419   int read_len = std::min(data_len, cached_min_len_);
 420   if (!read_len)
 421     return 0;
 422
 423   int rv = 0;
 424   if (sparse_entry_) {
 425     rv = entry->ReadSparseData(current_range_start_, data, read_len,
 426                                callback);
 427   } else {
 428     if (current_range_start_ > kint32max)
 429       return ERR_INVALID_ARGUMENT;
 430
 431     rv = entry->ReadData(kDataStream, static_cast<int>(current_range_start_),
 432                          data, read_len, callback);
 433   }
 434   return rv;
 435 }
 436
 437 int PartialData::CacheWrite(
 438     disk_cache::Entry* entry, IOBuffer* data, int data_len,
 439     const net::CompletionCallback& callback) {
 440   DVLOG(3) << "To write: " << data_len;
 441   if (sparse_entry_) {
 442     return entry->WriteSparseData(
 443         current_range_start_, data, data_len, callback);
 444   } else  {
 445     if (current_range_start_ > kint32max)
 446       return ERR_INVALID_ARGUMENT;
 447
 448     return entry->WriteData(kDataStream, static_cast<int>(current_range_start_),
 449                             data, data_len, callback, true);
 450   }
 451 }
 452
 453 void PartialData::OnCacheReadCompleted(int result) {
 454   DVLOG(3) << "Read: " << result;
 455   if (result > 0) {
 456     current_range_start_ += result;
 457     cached_min_len_ -= result;
 458     DCHECK_GE(cached_min_len_, 0);
 459   }
 460 }
 461
 462 void PartialData::OnNetworkReadCompleted(int result) {
 463   if (result > 0)
 464     current_range_start_ += result;
 465 }
 466
 467 int PartialData::GetNextRangeLen() {
 468   int64 range_len =
 469       byte_range_.HasLastBytePosition() ?
 470       byte_range_.last_byte_position() - current_range_start_ + 1 :
 471       kint32max;
 472   if (range_len > kint32max)
 473     range_len = kint32max;
 474   return static_cast<int32>(range_len);
 475 }
 476
 477 void PartialData::GetAvailableRangeCompleted(int result, int64 start) {
 478   DCHECK(!callback_.is_null());
 479   DCHECK_NE(ERR_IO_PENDING, result);
 480
 481   cached_start_ = start;
 482   cached_min_len_ = result;
 483   if (result >= 0)
 484     result = 1;  // Return success, go ahead and validate the entry.
 485
 486   CompletionCallback cb = callback_;
 487   callback_.Reset();
 488   cb.Run(result);
 489 }
 490
 491 }  // namespace net