AU: MultiHttpFetcher, an HttpFetcher for specific byte ranges

libcurl_http_fetcher.cc

 // Copyright (c) 2009 The Chromium OS Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "update_engine/libcurl_http_fetcher.h"
 #include <algorithm>
 #include "base/logging.h"
 
 using std::max;
 using std::make_pair;
@@ skipping 63 matching lines @@
   CHECK_EQ(curl_easy_setopt(curl_handle_, CURLOPT_CAPATH, kCACertificatesPath),
            CURLE_OK);
 
   CHECK_EQ(curl_multi_add_handle(curl_multi_handle_, curl_handle_), CURLM_OK);
   transfer_in_progress_ = true;
 }
 
 // Begins the transfer, which must not have already been started.
 void LibcurlHttpFetcher::BeginTransfer(const std::string& url) {
   transfer_size_ = -1;
-  bytes_downloaded_ = 0;
   resume_offset_ = 0;
   retry_count_ = 0;
   http_response_code_ = 0;
   ResumeTransfer(url);
   CurlPerformOnce();
 }
 
 void LibcurlHttpFetcher::TerminateTransfer() {
-  CleanUp();
+  if (in_write_callback_)
+    terminate_requested_ = true;
+  else
+    CleanUp();
 }
 
 void LibcurlHttpFetcher::CurlPerformOnce() {
   CHECK(transfer_in_progress_);
   int running_handles = 0;
   CURLMcode retcode = CURLM_CALL_MULTI_PERFORM;
 
   // libcurl may request that we immediately call curl_multi_perform after it
   // returns, so we do. libcurl promises that curl_multi_perform will not block.
   while (CURLM_CALL_MULTI_PERFORM == retcode) {
     retcode = curl_multi_perform(curl_multi_handle_, &running_handles);
+    if (terminate_requested_) {
+      CleanUp();
+      return;
+    }
   }
   if (0 == running_handles) {
-    long http_response_code = 0;
-    if (curl_easy_getinfo(curl_handle_,
-                          CURLINFO_RESPONSE_CODE,
-                          &http_response_code) == CURLE_OK) {
-      LOG(INFO) << "HTTP response code: " << http_response_code;
+    GetHttpResponseCode();
+    if (http_response_code_) {
+      LOG(INFO) << "HTTP response code: " << http_response_code_;
     } else {
       LOG(ERROR) << "Unable to get http response code.";
     }
-    http_response_code_ = static_cast<int>(http_response_code);
 
     // we're done!
     CleanUp();
 
     if ((transfer_size_ >= 0) && (bytes_downloaded_ < transfer_size_)) {
       // Need to restart transfer
       retry_count_++;
       LOG(INFO) << "Restarting transfer b/c we finished, had downloaded "
                 << bytes_downloaded_ << " bytes, but transfer_size_ is "
                 << transfer_size_ << ". retry_count: " << retry_count_;
       if (retry_count_ > kMaxRetriesCount) {
         if (delegate_)
           delegate_->TransferComplete(this, false);  // success
       } else {
         g_timeout_add_seconds(retry_seconds_,
                               &LibcurlHttpFetcher::StaticRetryTimeoutCallback,
                               this);
       }
       return;
     } else {
       if (delegate_) {
         // success is when http_response_code is 2xx
-        bool success = (http_response_code >= 200) &&
-            (http_response_code < 300);
+        bool success = (http_response_code_ >= 200) &&
+            (http_response_code_ < 300);
         delegate_->TransferComplete(this, success);
       }
     }
   } else {
     // set up callback
     SetupMainloopSources();
   }
 }
 
 size_t LibcurlHttpFetcher::LibcurlWrite(void *ptr, size_t size, size_t nmemb) {
+  GetHttpResponseCode();
   {
     double transfer_size_double;
     CHECK_EQ(curl_easy_getinfo(curl_handle_,
                                CURLINFO_CONTENT_LENGTH_DOWNLOAD,
                                &transfer_size_double), CURLE_OK);
     off_t new_transfer_size = static_cast<off_t>(transfer_size_double);
     if (new_transfer_size > 0) {
       transfer_size_ = resume_offset_ + new_transfer_size;
     }
   }
   bytes_downloaded_ += size * nmemb;
+  in_write_callback_ = true;
   if (delegate_)
     delegate_->ReceivedBytes(this, reinterpret_cast<char*>(ptr), size * nmemb);
+  in_write_callback_ = false;
   return size * nmemb;
 }
 
 void LibcurlHttpFetcher::Pause() {
   CHECK(curl_handle_);
   CHECK(transfer_in_progress_);
   CHECK_EQ(curl_easy_pause(curl_handle_, CURLPAUSE_ALL), CURLE_OK);
 }
 
 void LibcurlHttpFetcher::Unpause() {
@@ skipping 114 matching lines @@
     curl_easy_cleanup(curl_handle_);
     curl_handle_ = NULL;
   }
   if (curl_multi_handle_) {
     CHECK_EQ(curl_multi_cleanup(curl_multi_handle_), CURLM_OK);
     curl_multi_handle_ = NULL;
   }
   transfer_in_progress_ = false;
 }
 
+void LibcurlHttpFetcher::GetHttpResponseCode() {
+  long http_response_code = 0;
+  if (curl_easy_getinfo(curl_handle_,
+                        CURLINFO_RESPONSE_CODE,
+                        &http_response_code) == CURLE_OK) {
+    http_response_code_ = static_cast<int>(http_response_code);
+  }
+}
+
 }  // namespace chromeos_update_engine