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      1 // Copyright 2013 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 "chrome/browser/extensions/blob_reader.h"
      6 
      7 #include "base/format_macros.h"
      8 #include "base/strings/string_util.h"
      9 #include "base/strings/stringprintf.h"
     10 #include "chrome/browser/profiles/profile.h"
     11 #include "content/public/browser/browser_thread.h"
     12 #include "net/http/http_request_headers.h"
     13 #include "net/http/http_response_headers.h"
     14 #include "net/url_request/url_fetcher.h"
     15 #include "net/url_request/url_request_context.h"
     16 #include "net/url_request/url_request_context_getter.h"
     17 
     18 BlobReader::BlobReader(Profile* profile,
     19                        const std::string& blob_uuid,
     20                        BlobReadCallback callback)
     21     : callback_(callback) {
     22   DCHECK_CURRENTLY_ON(content::BrowserThread::UI);
     23   GURL blob_url;
     24   if (StartsWithASCII(blob_uuid, "blob:blobinternal", true)) {
     25     // TODO(michaeln): remove support for deprecated blob urls
     26     blob_url = GURL(blob_uuid);
     27   } else {
     28     blob_url = GURL(std::string("blob:uuid/") + blob_uuid);
     29   }
     30   DCHECK(blob_url.is_valid());
     31   fetcher_.reset(net::URLFetcher::Create(
     32       blob_url, net::URLFetcher::GET,
     33       this));
     34   fetcher_->SetRequestContext(profile->GetRequestContext());
     35 }
     36 
     37 BlobReader::~BlobReader() { DCHECK_CURRENTLY_ON(content::BrowserThread::UI); }
     38 
     39 void BlobReader::SetByteRange(int64 offset, int64 length) {
     40   DCHECK_CURRENTLY_ON(content::BrowserThread::UI);
     41   CHECK_GE(offset, 0);
     42   CHECK_GT(length, 0);
     43   CHECK_LE(offset, kint64max - length);
     44 
     45   net::HttpRequestHeaders headers;
     46   headers.SetHeader(
     47       net::HttpRequestHeaders::kRange,
     48       base::StringPrintf("bytes=%" PRId64 "-%" PRId64, offset,
     49                          offset + length - 1));
     50   fetcher_->SetExtraRequestHeaders(headers.ToString());
     51 }
     52 
     53 void BlobReader::Start() {
     54   DCHECK_CURRENTLY_ON(content::BrowserThread::UI);
     55   fetcher_->Start();
     56 }
     57 
     58 // Overridden from net::URLFetcherDelegate.
     59 void BlobReader::OnURLFetchComplete(const net::URLFetcher* source) {
     60   DCHECK_CURRENTLY_ON(content::BrowserThread::UI);
     61   scoped_ptr<std::string> response(new std::string);
     62   int64 first = 0, last = 0, length = 0;
     63   source->GetResponseAsString(response.get());
     64   source->GetResponseHeaders()->GetContentRange(&first, &last, &length);
     65   callback_.Run(response.Pass(), length);
     66 
     67   delete this;
     68 }
     69