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      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 "google_apis/drive/base_requests.h"
      6 
      7 #include "base/json/json_reader.h"
      8 #include "base/location.h"
      9 #include "base/sequenced_task_runner.h"
     10 #include "base/strings/string_number_conversions.h"
     11 #include "base/strings/stringprintf.h"
     12 #include "base/task_runner_util.h"
     13 #include "base/values.h"
     14 #include "google_apis/drive/request_sender.h"
     15 #include "google_apis/drive/task_util.h"
     16 #include "net/base/io_buffer.h"
     17 #include "net/base/load_flags.h"
     18 #include "net/base/net_errors.h"
     19 #include "net/http/http_byte_range.h"
     20 #include "net/http/http_response_headers.h"
     21 #include "net/http/http_util.h"
     22 #include "net/url_request/url_fetcher.h"
     23 #include "net/url_request/url_request_status.h"
     24 
     25 using net::URLFetcher;
     26 
     27 namespace {
     28 
     29 // Template for optional OAuth2 authorization HTTP header.
     30 const char kAuthorizationHeaderFormat[] = "Authorization: Bearer %s";
     31 // Template for GData API version HTTP header.
     32 const char kGDataVersionHeader[] = "GData-Version: 3.0";
     33 
     34 // Maximum number of attempts for re-authentication per request.
     35 const int kMaxReAuthenticateAttemptsPerRequest = 1;
     36 
     37 // Template for initiate upload of both GData WAPI and Drive API v2.
     38 const char kUploadContentType[] = "X-Upload-Content-Type: ";
     39 const char kUploadContentLength[] = "X-Upload-Content-Length: ";
     40 const char kUploadResponseLocation[] = "location";
     41 
     42 // Template for upload data range of both GData WAPI and Drive API v2.
     43 const char kUploadContentRange[] = "Content-Range: bytes ";
     44 const char kUploadResponseRange[] = "range";
     45 
     46 // Parse JSON string to base::Value object.
     47 scoped_ptr<base::Value> ParseJsonInternal(const std::string& json) {
     48   int error_code = -1;
     49   std::string error_message;
     50   scoped_ptr<base::Value> value(base::JSONReader::ReadAndReturnError(
     51       json, base::JSON_PARSE_RFC, &error_code, &error_message));
     52 
     53   if (!value.get()) {
     54     std::string trimmed_json;
     55     if (json.size() < 80) {
     56       trimmed_json  = json;
     57     } else {
     58       // Take the first 50 and the last 10 bytes.
     59       trimmed_json = base::StringPrintf(
     60           "%s [%s bytes] %s",
     61           json.substr(0, 50).c_str(),
     62           base::Uint64ToString(json.size() - 60).c_str(),
     63           json.substr(json.size() - 10).c_str());
     64     }
     65     LOG(WARNING) << "Error while parsing entry response: " << error_message
     66                  << ", code: " << error_code << ", json:\n" << trimmed_json;
     67   }
     68   return value.Pass();
     69 }
     70 
     71 // Returns response headers as a string. Returns a warning message if
     72 // |url_fetcher| does not contain a valid response. Used only for debugging.
     73 std::string GetResponseHeadersAsString(
     74     const URLFetcher* url_fetcher) {
     75   // net::HttpResponseHeaders::raw_headers(), as the name implies, stores
     76   // all headers in their raw format, i.e each header is null-terminated.
     77   // So logging raw_headers() only shows the first header, which is probably
     78   // the status line.  GetNormalizedHeaders, on the other hand, will show all
     79   // the headers, one per line, which is probably what we want.
     80   std::string headers;
     81   // Check that response code indicates response headers are valid (i.e. not
     82   // malformed) before we retrieve the headers.
     83   if (url_fetcher->GetResponseCode() == URLFetcher::RESPONSE_CODE_INVALID) {
     84     headers.assign("Response headers are malformed!!");
     85   } else {
     86     url_fetcher->GetResponseHeaders()->GetNormalizedHeaders(&headers);
     87   }
     88   return headers;
     89 }
     90 
     91 bool IsSuccessfulResponseCode(int response_code) {
     92   return 200 <= response_code && response_code <= 299;
     93 }
     94 
     95 }  // namespace
     96 
     97 namespace google_apis {
     98 
     99 void ParseJson(base::TaskRunner* blocking_task_runner,
    100                const std::string& json,
    101                const ParseJsonCallback& callback) {
    102   base::PostTaskAndReplyWithResult(
    103       blocking_task_runner,
    104       FROM_HERE,
    105       base::Bind(&ParseJsonInternal, json),
    106       callback);
    107 }
    108 
    109 //=========================== ResponseWriter ==================================
    110 ResponseWriter::ResponseWriter(base::SequencedTaskRunner* file_task_runner,
    111                                const base::FilePath& file_path,
    112                                const GetContentCallback& get_content_callback)
    113     : get_content_callback_(get_content_callback),
    114       weak_ptr_factory_(this) {
    115   if (!file_path.empty()) {
    116     file_writer_.reset(
    117         new net::URLFetcherFileWriter(file_task_runner, file_path));
    118   }
    119 }
    120 
    121 ResponseWriter::~ResponseWriter() {
    122 }
    123 
    124 void ResponseWriter::DisownFile() {
    125   DCHECK(file_writer_);
    126   file_writer_->DisownFile();
    127 }
    128 
    129 int ResponseWriter::Initialize(const net::CompletionCallback& callback) {
    130   if (file_writer_)
    131     return file_writer_->Initialize(callback);
    132 
    133   data_.clear();
    134   return net::OK;
    135 }
    136 
    137 int ResponseWriter::Write(net::IOBuffer* buffer,
    138                           int num_bytes,
    139                           const net::CompletionCallback& callback) {
    140   if (!get_content_callback_.is_null()) {
    141     get_content_callback_.Run(
    142         HTTP_SUCCESS,
    143         make_scoped_ptr(new std::string(buffer->data(), num_bytes)));
    144   }
    145 
    146   if (file_writer_) {
    147     const int result = file_writer_->Write(
    148         buffer, num_bytes,
    149         base::Bind(&ResponseWriter::DidWrite,
    150                    weak_ptr_factory_.GetWeakPtr(),
    151                    make_scoped_refptr(buffer), callback));
    152     if (result != net::ERR_IO_PENDING)
    153       DidWrite(buffer, net::CompletionCallback(), result);
    154     return result;
    155   }
    156 
    157   data_.append(buffer->data(), num_bytes);
    158   return num_bytes;
    159 }
    160 
    161 int ResponseWriter::Finish(const net::CompletionCallback& callback) {
    162   if (file_writer_)
    163     return file_writer_->Finish(callback);
    164 
    165   return net::OK;
    166 }
    167 
    168 void ResponseWriter::DidWrite(scoped_refptr<net::IOBuffer> buffer,
    169                               const net::CompletionCallback& callback,
    170                               int result) {
    171   if (result > 0) {
    172     // Even if file_writer_ is used, append the data to |data_|, so that it can
    173     // be used to get error information in case of server side errors.
    174     // The size limit is to avoid consuming too much redundant memory.
    175     const size_t kMaxStringSize = 1024*1024;
    176     if (data_.size() < kMaxStringSize) {
    177       data_.append(buffer->data(), std::min(static_cast<size_t>(result),
    178                                             kMaxStringSize - data_.size()));
    179     }
    180   }
    181 
    182   if (!callback.is_null())
    183     callback.Run(result);
    184 }
    185 
    186 //============================ UrlFetchRequestBase ===========================
    187 
    188 UrlFetchRequestBase::UrlFetchRequestBase(RequestSender* sender)
    189     : re_authenticate_count_(0),
    190       sender_(sender),
    191       error_code_(GDATA_OTHER_ERROR),
    192       weak_ptr_factory_(this) {
    193 }
    194 
    195 UrlFetchRequestBase::~UrlFetchRequestBase() {}
    196 
    197 void UrlFetchRequestBase::Start(const std::string& access_token,
    198                                 const std::string& custom_user_agent,
    199                                 const ReAuthenticateCallback& callback) {
    200   DCHECK(CalledOnValidThread());
    201   DCHECK(!access_token.empty());
    202   DCHECK(!callback.is_null());
    203   DCHECK(re_authenticate_callback_.is_null());
    204 
    205   re_authenticate_callback_ = callback;
    206 
    207   GURL url = GetURL();
    208   if (url.is_empty()) {
    209     // Error is found on generating the url. Send the error message to the
    210     // callback, and then return immediately without trying to connect
    211     // to the server.
    212     RunCallbackOnPrematureFailure(GDATA_OTHER_ERROR);
    213     return;
    214   }
    215   DVLOG(1) << "URL: " << url.spec();
    216 
    217   URLFetcher::RequestType request_type = GetRequestType();
    218   url_fetcher_.reset(
    219       URLFetcher::Create(url, request_type, this));
    220   url_fetcher_->SetRequestContext(sender_->url_request_context_getter());
    221   // Always set flags to neither send nor save cookies.
    222   url_fetcher_->SetLoadFlags(
    223       net::LOAD_DO_NOT_SEND_COOKIES | net::LOAD_DO_NOT_SAVE_COOKIES |
    224       net::LOAD_DISABLE_CACHE);
    225 
    226   base::FilePath output_file_path;
    227   GetContentCallback get_content_callback;
    228   GetOutputFilePath(&output_file_path, &get_content_callback);
    229   if (!get_content_callback.is_null())
    230     get_content_callback = CreateRelayCallback(get_content_callback);
    231   response_writer_ = new ResponseWriter(blocking_task_runner(),
    232                                         output_file_path,
    233                                         get_content_callback);
    234   url_fetcher_->SaveResponseWithWriter(
    235       scoped_ptr<net::URLFetcherResponseWriter>(response_writer_));
    236 
    237   // Add request headers.
    238   // Note that SetExtraRequestHeaders clears the current headers and sets it
    239   // to the passed-in headers, so calling it for each header will result in
    240   // only the last header being set in request headers.
    241   if (!custom_user_agent.empty())
    242     url_fetcher_->AddExtraRequestHeader("User-Agent: " + custom_user_agent);
    243   url_fetcher_->AddExtraRequestHeader(kGDataVersionHeader);
    244   url_fetcher_->AddExtraRequestHeader(
    245       base::StringPrintf(kAuthorizationHeaderFormat, access_token.data()));
    246   std::vector<std::string> headers = GetExtraRequestHeaders();
    247   for (size_t i = 0; i < headers.size(); ++i) {
    248     url_fetcher_->AddExtraRequestHeader(headers[i]);
    249     DVLOG(1) << "Extra header: " << headers[i];
    250   }
    251 
    252   // Set upload data if available.
    253   std::string upload_content_type;
    254   std::string upload_content;
    255   if (GetContentData(&upload_content_type, &upload_content)) {
    256     url_fetcher_->SetUploadData(upload_content_type, upload_content);
    257   } else {
    258     base::FilePath local_file_path;
    259     int64 range_offset = 0;
    260     int64 range_length = 0;
    261     if (GetContentFile(&local_file_path, &range_offset, &range_length,
    262                        &upload_content_type)) {
    263       url_fetcher_->SetUploadFilePath(
    264           upload_content_type,
    265           local_file_path,
    266           range_offset,
    267           range_length,
    268           blocking_task_runner());
    269     } else {
    270       // Even if there is no content data, UrlFetcher requires to set empty
    271       // upload data string for POST, PUT and PATCH methods, explicitly.
    272       // It is because that most requests of those methods have non-empty
    273       // body, and UrlFetcher checks whether it is actually not forgotten.
    274       if (request_type == URLFetcher::POST ||
    275           request_type == URLFetcher::PUT ||
    276           request_type == URLFetcher::PATCH) {
    277         // Set empty upload content-type and upload content, so that
    278         // the request will have no "Content-type: " header and no content.
    279         url_fetcher_->SetUploadData(std::string(), std::string());
    280       }
    281     }
    282   }
    283 
    284   url_fetcher_->Start();
    285 }
    286 
    287 URLFetcher::RequestType UrlFetchRequestBase::GetRequestType() const {
    288   return URLFetcher::GET;
    289 }
    290 
    291 std::vector<std::string> UrlFetchRequestBase::GetExtraRequestHeaders() const {
    292   return std::vector<std::string>();
    293 }
    294 
    295 bool UrlFetchRequestBase::GetContentData(std::string* upload_content_type,
    296                                          std::string* upload_content) {
    297   return false;
    298 }
    299 
    300 bool UrlFetchRequestBase::GetContentFile(base::FilePath* local_file_path,
    301                                          int64* range_offset,
    302                                          int64* range_length,
    303                                          std::string* upload_content_type) {
    304   return false;
    305 }
    306 
    307 void UrlFetchRequestBase::GetOutputFilePath(
    308     base::FilePath* local_file_path,
    309     GetContentCallback* get_content_callback) {
    310 }
    311 
    312 void UrlFetchRequestBase::Cancel() {
    313   response_writer_ = NULL;
    314   url_fetcher_.reset(NULL);
    315   RunCallbackOnPrematureFailure(GDATA_CANCELLED);
    316   sender_->RequestFinished(this);
    317 }
    318 
    319 GDataErrorCode UrlFetchRequestBase::GetErrorCode() {
    320   return error_code_;
    321 }
    322 
    323 bool UrlFetchRequestBase::CalledOnValidThread() {
    324   return thread_checker_.CalledOnValidThread();
    325 }
    326 
    327 base::SequencedTaskRunner* UrlFetchRequestBase::blocking_task_runner() const {
    328   return sender_->blocking_task_runner();
    329 }
    330 
    331 void UrlFetchRequestBase::OnProcessURLFetchResultsComplete() {
    332   sender_->RequestFinished(this);
    333 }
    334 
    335 void UrlFetchRequestBase::OnURLFetchComplete(const URLFetcher* source) {
    336   DVLOG(1) << "Response headers:\n" << GetResponseHeadersAsString(source);
    337 
    338   // Determine error code.
    339   error_code_ = static_cast<GDataErrorCode>(source->GetResponseCode());
    340   if (!source->GetStatus().is_success()) {
    341     switch (source->GetStatus().error()) {
    342       case net::ERR_NETWORK_CHANGED:
    343         error_code_ = GDATA_NO_CONNECTION;
    344         break;
    345       default:
    346         error_code_ = GDATA_OTHER_ERROR;
    347     }
    348   }
    349 
    350   // The server may return detailed error status in JSON.
    351   // See https://developers.google.com/drive/handle-errors
    352   if (!IsSuccessfulResponseCode(error_code_)) {
    353     DVLOG(1) << response_writer_->data();
    354 
    355     const char kErrorKey[] = "error";
    356     const char kErrorErrorsKey[] = "errors";
    357     const char kErrorReasonKey[] = "reason";
    358     const char kErrorMessageKey[] = "message";
    359     const char kErrorReasonRateLimitExceeded[] = "rateLimitExceeded";
    360     const char kErrorReasonUserRateLimitExceeded[] = "userRateLimitExceeded";
    361 
    362     scoped_ptr<base::Value> value(ParseJsonInternal(response_writer_->data()));
    363     base::DictionaryValue* dictionary = NULL;
    364     base::DictionaryValue* error = NULL;
    365     if (value &&
    366         value->GetAsDictionary(&dictionary) &&
    367         dictionary->GetDictionaryWithoutPathExpansion(kErrorKey, &error)) {
    368       // Get error message.
    369       std::string message;
    370       error->GetStringWithoutPathExpansion(kErrorMessageKey, &message);
    371       DLOG(ERROR) << "code: " << error_code_ << ", message: " << message;
    372 
    373       // Override the error code based on the reason of the first error.
    374       base::ListValue* errors = NULL;
    375       base::DictionaryValue* first_error = NULL;
    376       if (error->GetListWithoutPathExpansion(kErrorErrorsKey, &errors) &&
    377           errors->GetDictionary(0, &first_error)) {
    378         std::string reason;
    379         first_error->GetStringWithoutPathExpansion(kErrorReasonKey, &reason);
    380         if (reason == kErrorReasonRateLimitExceeded ||
    381             reason == kErrorReasonUserRateLimitExceeded)
    382           error_code_ = HTTP_SERVICE_UNAVAILABLE;
    383       }
    384     }
    385   }
    386 
    387   // Handle authentication failure.
    388   if (error_code_ == HTTP_UNAUTHORIZED) {
    389     if (++re_authenticate_count_ <= kMaxReAuthenticateAttemptsPerRequest) {
    390       // Reset re_authenticate_callback_ so Start() can be called again.
    391       ReAuthenticateCallback callback = re_authenticate_callback_;
    392       re_authenticate_callback_.Reset();
    393       callback.Run(this);
    394       return;
    395     }
    396 
    397     OnAuthFailed(error_code_);
    398     return;
    399   }
    400 
    401   // Overridden by each specialization
    402   ProcessURLFetchResults(source);
    403 }
    404 
    405 void UrlFetchRequestBase::OnAuthFailed(GDataErrorCode code) {
    406   RunCallbackOnPrematureFailure(code);
    407   sender_->RequestFinished(this);
    408 }
    409 
    410 base::WeakPtr<AuthenticatedRequestInterface>
    411 UrlFetchRequestBase::GetWeakPtr() {
    412   return weak_ptr_factory_.GetWeakPtr();
    413 }
    414 
    415 //============================ EntryActionRequest ============================
    416 
    417 EntryActionRequest::EntryActionRequest(RequestSender* sender,
    418                                        const EntryActionCallback& callback)
    419     : UrlFetchRequestBase(sender),
    420       callback_(callback) {
    421   DCHECK(!callback_.is_null());
    422 }
    423 
    424 EntryActionRequest::~EntryActionRequest() {}
    425 
    426 void EntryActionRequest::ProcessURLFetchResults(const URLFetcher* source) {
    427   callback_.Run(GetErrorCode());
    428   OnProcessURLFetchResultsComplete();
    429 }
    430 
    431 void EntryActionRequest::RunCallbackOnPrematureFailure(GDataErrorCode code) {
    432   callback_.Run(code);
    433 }
    434 
    435 //============================== GetDataRequest ==============================
    436 
    437 GetDataRequest::GetDataRequest(RequestSender* sender,
    438                                const GetDataCallback& callback)
    439     : UrlFetchRequestBase(sender),
    440       callback_(callback),
    441       weak_ptr_factory_(this) {
    442   DCHECK(!callback_.is_null());
    443 }
    444 
    445 GetDataRequest::~GetDataRequest() {}
    446 
    447 void GetDataRequest::ParseResponse(GDataErrorCode fetch_error_code,
    448                                    const std::string& data) {
    449   DCHECK(CalledOnValidThread());
    450 
    451   VLOG(1) << "JSON received from " << GetURL().spec() << ": "
    452           << data.size() << " bytes";
    453   ParseJson(blocking_task_runner(),
    454             data,
    455             base::Bind(&GetDataRequest::OnDataParsed,
    456                        weak_ptr_factory_.GetWeakPtr(),
    457                        fetch_error_code));
    458 }
    459 
    460 void GetDataRequest::ProcessURLFetchResults(const URLFetcher* source) {
    461   GDataErrorCode fetch_error_code = GetErrorCode();
    462 
    463   switch (fetch_error_code) {
    464     case HTTP_SUCCESS:
    465     case HTTP_CREATED:
    466       ParseResponse(fetch_error_code, response_writer()->data());
    467       break;
    468     default:
    469       RunCallbackOnPrematureFailure(fetch_error_code);
    470       OnProcessURLFetchResultsComplete();
    471       break;
    472   }
    473 }
    474 
    475 void GetDataRequest::RunCallbackOnPrematureFailure(
    476     GDataErrorCode fetch_error_code) {
    477   callback_.Run(fetch_error_code, scoped_ptr<base::Value>());
    478 }
    479 
    480 void GetDataRequest::OnDataParsed(GDataErrorCode fetch_error_code,
    481                                   scoped_ptr<base::Value> value) {
    482   DCHECK(CalledOnValidThread());
    483 
    484   if (!value.get())
    485     fetch_error_code = GDATA_PARSE_ERROR;
    486 
    487   callback_.Run(fetch_error_code, value.Pass());
    488   OnProcessURLFetchResultsComplete();
    489 }
    490 
    491 //========================= InitiateUploadRequestBase ========================
    492 
    493 InitiateUploadRequestBase::InitiateUploadRequestBase(
    494     RequestSender* sender,
    495     const InitiateUploadCallback& callback,
    496     const std::string& content_type,
    497     int64 content_length)
    498     : UrlFetchRequestBase(sender),
    499       callback_(callback),
    500       content_type_(content_type),
    501       content_length_(content_length) {
    502   DCHECK(!callback_.is_null());
    503   DCHECK(!content_type_.empty());
    504   DCHECK_GE(content_length_, 0);
    505 }
    506 
    507 InitiateUploadRequestBase::~InitiateUploadRequestBase() {}
    508 
    509 void InitiateUploadRequestBase::ProcessURLFetchResults(
    510     const URLFetcher* source) {
    511   GDataErrorCode code = GetErrorCode();
    512 
    513   std::string upload_location;
    514   if (code == HTTP_SUCCESS) {
    515     // Retrieve value of the first "Location" header.
    516     source->GetResponseHeaders()->EnumerateHeader(NULL,
    517                                                   kUploadResponseLocation,
    518                                                   &upload_location);
    519   }
    520 
    521   callback_.Run(code, GURL(upload_location));
    522   OnProcessURLFetchResultsComplete();
    523 }
    524 
    525 void InitiateUploadRequestBase::RunCallbackOnPrematureFailure(
    526     GDataErrorCode code) {
    527   callback_.Run(code, GURL());
    528 }
    529 
    530 std::vector<std::string>
    531 InitiateUploadRequestBase::GetExtraRequestHeaders() const {
    532   std::vector<std::string> headers;
    533   headers.push_back(kUploadContentType + content_type_);
    534   headers.push_back(
    535       kUploadContentLength + base::Int64ToString(content_length_));
    536   return headers;
    537 }
    538 
    539 //============================ UploadRangeResponse =============================
    540 
    541 UploadRangeResponse::UploadRangeResponse()
    542     : code(HTTP_SUCCESS),
    543       start_position_received(0),
    544       end_position_received(0) {
    545 }
    546 
    547 UploadRangeResponse::UploadRangeResponse(GDataErrorCode code,
    548                                          int64 start_position_received,
    549                                          int64 end_position_received)
    550     : code(code),
    551       start_position_received(start_position_received),
    552       end_position_received(end_position_received) {
    553 }
    554 
    555 UploadRangeResponse::~UploadRangeResponse() {
    556 }
    557 
    558 //========================== UploadRangeRequestBase ==========================
    559 
    560 UploadRangeRequestBase::UploadRangeRequestBase(RequestSender* sender,
    561                                                const GURL& upload_url)
    562     : UrlFetchRequestBase(sender),
    563       upload_url_(upload_url),
    564       weak_ptr_factory_(this) {
    565 }
    566 
    567 UploadRangeRequestBase::~UploadRangeRequestBase() {}
    568 
    569 GURL UploadRangeRequestBase::GetURL() const {
    570   // This is very tricky to get json from this request. To do that, &alt=json
    571   // has to be appended not here but in InitiateUploadRequestBase::GetURL().
    572   return upload_url_;
    573 }
    574 
    575 URLFetcher::RequestType UploadRangeRequestBase::GetRequestType() const {
    576   return URLFetcher::PUT;
    577 }
    578 
    579 void UploadRangeRequestBase::ProcessURLFetchResults(
    580     const URLFetcher* source) {
    581   GDataErrorCode code = GetErrorCode();
    582   net::HttpResponseHeaders* hdrs = source->GetResponseHeaders();
    583 
    584   if (code == HTTP_RESUME_INCOMPLETE) {
    585     // Retrieve value of the first "Range" header.
    586     // The Range header is appeared only if there is at least one received
    587     // byte. So, initialize the positions by 0 so that the [0,0) will be
    588     // returned via the |callback_| for empty data case.
    589     int64 start_position_received = 0;
    590     int64 end_position_received = 0;
    591     std::string range_received;
    592     hdrs->EnumerateHeader(NULL, kUploadResponseRange, &range_received);
    593     if (!range_received.empty()) {  // Parse the range header.
    594       std::vector<net::HttpByteRange> ranges;
    595       if (net::HttpUtil::ParseRangeHeader(range_received, &ranges) &&
    596           !ranges.empty() ) {
    597         // We only care about the first start-end pair in the range.
    598         //
    599         // Range header represents the range inclusively, while we are treating
    600         // ranges exclusively (i.e., end_position_received should be one passed
    601         // the last valid index). So "+ 1" is added.
    602         start_position_received = ranges[0].first_byte_position();
    603         end_position_received = ranges[0].last_byte_position() + 1;
    604       }
    605     }
    606     // The Range header has the received data range, so the start position
    607     // should be always 0.
    608     DCHECK_EQ(start_position_received, 0);
    609 
    610     OnRangeRequestComplete(UploadRangeResponse(code,
    611                                                start_position_received,
    612                                                end_position_received),
    613                            scoped_ptr<base::Value>());
    614 
    615     OnProcessURLFetchResultsComplete();
    616   } else if (code == HTTP_CREATED || code == HTTP_SUCCESS) {
    617     // The upload is successfully done. Parse the response which should be
    618     // the entry's metadata.
    619     ParseJson(blocking_task_runner(),
    620               response_writer()->data(),
    621               base::Bind(&UploadRangeRequestBase::OnDataParsed,
    622                          weak_ptr_factory_.GetWeakPtr(),
    623                          code));
    624   } else {
    625     // Failed to upload. Run callbacks to notify the error.
    626     OnRangeRequestComplete(
    627         UploadRangeResponse(code, -1, -1), scoped_ptr<base::Value>());
    628     OnProcessURLFetchResultsComplete();
    629   }
    630 }
    631 
    632 void UploadRangeRequestBase::OnDataParsed(GDataErrorCode code,
    633                                           scoped_ptr<base::Value> value) {
    634   DCHECK(CalledOnValidThread());
    635   DCHECK(code == HTTP_CREATED || code == HTTP_SUCCESS);
    636 
    637   OnRangeRequestComplete(UploadRangeResponse(code, -1, -1), value.Pass());
    638   OnProcessURLFetchResultsComplete();
    639 }
    640 
    641 void UploadRangeRequestBase::RunCallbackOnPrematureFailure(
    642     GDataErrorCode code) {
    643   OnRangeRequestComplete(
    644       UploadRangeResponse(code, 0, 0), scoped_ptr<base::Value>());
    645 }
    646 
    647 //========================== ResumeUploadRequestBase =========================
    648 
    649 ResumeUploadRequestBase::ResumeUploadRequestBase(
    650     RequestSender* sender,
    651     const GURL& upload_location,
    652     int64 start_position,
    653     int64 end_position,
    654     int64 content_length,
    655     const std::string& content_type,
    656     const base::FilePath& local_file_path)
    657     : UploadRangeRequestBase(sender, upload_location),
    658       start_position_(start_position),
    659       end_position_(end_position),
    660       content_length_(content_length),
    661       content_type_(content_type),
    662       local_file_path_(local_file_path) {
    663   DCHECK_LE(start_position_, end_position_);
    664 }
    665 
    666 ResumeUploadRequestBase::~ResumeUploadRequestBase() {}
    667 
    668 std::vector<std::string>
    669 ResumeUploadRequestBase::GetExtraRequestHeaders() const {
    670   if (content_length_ == 0) {
    671     // For uploading an empty document, just PUT an empty content.
    672     DCHECK_EQ(start_position_, 0);
    673     DCHECK_EQ(end_position_, 0);
    674     return std::vector<std::string>();
    675   }
    676 
    677   // The header looks like
    678   // Content-Range: bytes <start_position>-<end_position>/<content_length>
    679   // for example:
    680   // Content-Range: bytes 7864320-8388607/13851821
    681   // The header takes inclusive range, so we adjust by "end_position - 1".
    682   DCHECK_GE(start_position_, 0);
    683   DCHECK_GT(end_position_, 0);
    684   DCHECK_GE(content_length_, 0);
    685 
    686   std::vector<std::string> headers;
    687   headers.push_back(
    688       std::string(kUploadContentRange) +
    689       base::Int64ToString(start_position_) + "-" +
    690       base::Int64ToString(end_position_ - 1) + "/" +
    691       base::Int64ToString(content_length_));
    692   return headers;
    693 }
    694 
    695 bool ResumeUploadRequestBase::GetContentFile(
    696     base::FilePath* local_file_path,
    697     int64* range_offset,
    698     int64* range_length,
    699     std::string* upload_content_type) {
    700   if (start_position_ == end_position_) {
    701     // No content data.
    702     return false;
    703   }
    704 
    705   *local_file_path = local_file_path_;
    706   *range_offset = start_position_;
    707   *range_length = end_position_ - start_position_;
    708   *upload_content_type = content_type_;
    709   return true;
    710 }
    711 
    712 //======================== GetUploadStatusRequestBase ========================
    713 
    714 GetUploadStatusRequestBase::GetUploadStatusRequestBase(RequestSender* sender,
    715                                                        const GURL& upload_url,
    716                                                        int64 content_length)
    717     : UploadRangeRequestBase(sender, upload_url),
    718       content_length_(content_length) {}
    719 
    720 GetUploadStatusRequestBase::~GetUploadStatusRequestBase() {}
    721 
    722 std::vector<std::string>
    723 GetUploadStatusRequestBase::GetExtraRequestHeaders() const {
    724   // The header looks like
    725   // Content-Range: bytes */<content_length>
    726   // for example:
    727   // Content-Range: bytes */13851821
    728   DCHECK_GE(content_length_, 0);
    729 
    730   std::vector<std::string> headers;
    731   headers.push_back(
    732       std::string(kUploadContentRange) + "*/" +
    733       base::Int64ToString(content_length_));
    734   return headers;
    735 }
    736 
    737 //============================ DownloadFileRequestBase =========================
    738 
    739 DownloadFileRequestBase::DownloadFileRequestBase(
    740     RequestSender* sender,
    741     const DownloadActionCallback& download_action_callback,
    742     const GetContentCallback& get_content_callback,
    743     const ProgressCallback& progress_callback,
    744     const GURL& download_url,
    745     const base::FilePath& output_file_path)
    746     : UrlFetchRequestBase(sender),
    747       download_action_callback_(download_action_callback),
    748       get_content_callback_(get_content_callback),
    749       progress_callback_(progress_callback),
    750       download_url_(download_url),
    751       output_file_path_(output_file_path) {
    752   DCHECK(!download_action_callback_.is_null());
    753   DCHECK(!output_file_path_.empty());
    754   // get_content_callback may be null.
    755 }
    756 
    757 DownloadFileRequestBase::~DownloadFileRequestBase() {}
    758 
    759 // Overridden from UrlFetchRequestBase.
    760 GURL DownloadFileRequestBase::GetURL() const {
    761   return download_url_;
    762 }
    763 
    764 void DownloadFileRequestBase::GetOutputFilePath(
    765     base::FilePath* local_file_path,
    766     GetContentCallback* get_content_callback) {
    767   // Configure so that the downloaded content is saved to |output_file_path_|.
    768   *local_file_path = output_file_path_;
    769   *get_content_callback = get_content_callback_;
    770 }
    771 
    772 void DownloadFileRequestBase::OnURLFetchDownloadProgress(
    773     const URLFetcher* source,
    774     int64 current,
    775     int64 total) {
    776   if (!progress_callback_.is_null())
    777     progress_callback_.Run(current, total);
    778 }
    779 
    780 void DownloadFileRequestBase::ProcessURLFetchResults(const URLFetcher* source) {
    781   GDataErrorCode code = GetErrorCode();
    782 
    783   // Take over the ownership of the the downloaded temp file.
    784   base::FilePath temp_file;
    785   if (code == HTTP_SUCCESS) {
    786     response_writer()->DisownFile();
    787     temp_file = output_file_path_;
    788   }
    789 
    790   download_action_callback_.Run(code, temp_file);
    791   OnProcessURLFetchResultsComplete();
    792 }
    793 
    794 void DownloadFileRequestBase::RunCallbackOnPrematureFailure(
    795     GDataErrorCode code) {
    796   download_action_callback_.Run(code, base::FilePath());
    797 }
    798 
    799 }  // namespace google_apis
    800