Revert "Reland: URLRequestJob: change ReadRawData contract"

chrome/browser/chromeos/fileapi/external_file_url_request_job.cc

Index: chrome/browser/chromeos/fileapi/external_file_url_request_job.cc
diff --git a/chrome/browser/chromeos/fileapi/external_file_url_request_job.cc b/chrome/browser/chromeos/fileapi/external_file_url_request_job.cc
index 917cbcbe95efc79ad5da4637d562a22e80087259..676e356be7aed891b1dec0e42b39ae4c07dae752 100644
--- a/chrome/browser/chromeos/fileapi/external_file_url_request_job.cc
+++ b/chrome/browser/chromeos/fileapi/external_file_url_request_job.cc
@@ -10,7 +10,6 @@
 #include "base/bind.h"
 #include "base/logging.h"
 #include "base/memory/ref_counted.h"
-#include "base/thread_task_runner_handle.h"
 #include "chrome/browser/browser_process.h"
 #include "chrome/browser/chromeos/file_manager/fileapi_util.h"
 #include "chrome/browser/chromeos/fileapi/external_file_url_util.h"
@@ -20,6 +19,7 @@
 #include "content/public/browser/browser_thread.h"
 #include "content/public/browser/storage_partition.h"
 #include "content/public/common/url_constants.h"
+#include "net/base/net_errors.h"
 #include "net/http/http_byte_range.h"
 #include "net/http/http_request_headers.h"
 #include "net/http/http_response_info.h"
@@ -163,7 +163,6 @@ ExternalFileURLRequestJob::ExternalFileURLRequestJob(
     net::NetworkDelegate* network_delegate)
     : net::URLRequestJob(request, network_delegate),
       profile_id_(profile_id),
-      range_parse_result_(net::OK),
       remaining_bytes_(0),
       weak_ptr_factory_(this) {}
 
@@ -171,40 +170,24 @@ void ExternalFileURLRequestJob::SetExtraRequestHeaders(
     const net::HttpRequestHeaders& headers) {
   std::string range_header;
   if (headers.GetHeader(net::HttpRequestHeaders::kRange, &range_header)) {
-    // Currently this job only cares about the Range header, and only supports
-    // single range requests. Note that validation is deferred to Start,
-    // because NotifyStartError is not legal to call since the job has not
-    // started.
+    // Note: We only support single range requests.
     std::vector<net::HttpByteRange> ranges;
     if (net::HttpUtil::ParseRangeHeader(range_header, &ranges) &&
         ranges.size() == 1) {
       byte_range_ = ranges[0];
     } else {
-      range_parse_result_ = net::ERR_REQUEST_RANGE_NOT_SATISFIABLE;
+      // Failed to parse Range: header, so notify the error.
+      NotifyDone(net::URLRequestStatus(net::URLRequestStatus::FAILED,
+                                       net::ERR_REQUEST_RANGE_NOT_SATISFIABLE));
     }
   }
 }
 
 void ExternalFileURLRequestJob::Start() {
-  // Post a task to invoke StartAsync asynchronously to avoid re-entering the
-  // delegate, because NotifyStartError is not legal to call synchronously in
-  // Start().
-  base::ThreadTaskRunnerHandle::Get()->PostTask(
-      FROM_HERE, base::Bind(&ExternalFileURLRequestJob::StartAsync,
-                            weak_ptr_factory_.GetWeakPtr()));
-}
-
-void ExternalFileURLRequestJob::StartAsync() {
   DVLOG(1) << "Starting request";
   DCHECK_CURRENTLY_ON(BrowserThread::IO);
   DCHECK(!stream_reader_);
 
-  if (range_parse_result_ != net::OK) {
-    NotifyStartError(net::URLRequestStatus(net::URLRequestStatus::FAILED,
-                                           range_parse_result_));
-    return;
-  }
-
   // We only support GET request.
   if (request()->method() != "GET") {
     LOG(WARNING) << "Failed to start request: " << request()->method()
@@ -344,23 +327,37 @@ bool ExternalFileURLRequestJob::IsRedirectResponse(GURL* location,
   return true;
 }
 
-int ExternalFileURLRequestJob::ReadRawData(net::IOBuffer* buf, int buf_size) {
+bool ExternalFileURLRequestJob::ReadRawData(net::IOBuffer* buf,
+                                            int buf_size,
+                                            int* bytes_read) {
   DCHECK_CURRENTLY_ON(BrowserThread::IO);
   DCHECK(stream_reader_);
 
-  if (remaining_bytes_ == 0)
-    return 0;
+  if (remaining_bytes_ == 0) {
+    *bytes_read = 0;
+    return true;
+  }
 
   const int result = stream_reader_->Read(
       buf, std::min<int64>(buf_size, remaining_bytes_),
       base::Bind(&ExternalFileURLRequestJob::OnReadCompleted,
                  weak_ptr_factory_.GetWeakPtr()));
 
-  if (result < 0)
-    return result;
+  if (result == net::ERR_IO_PENDING) {
+    // The data is not yet available.
+    SetStatus(net::URLRequestStatus(net::URLRequestStatus::IO_PENDING, 0));
+    return false;
+  }
+  if (result < 0) {
+    // An error occurs.
+    NotifyDone(net::URLRequestStatus(net::URLRequestStatus::FAILED, result));
+    return false;
+  }
 
+  // Reading has been finished immediately.
+  *bytes_read = result;
   remaining_bytes_ -= result;
-  return result;
+  return true;
 }
 
 ExternalFileURLRequestJob::~ExternalFileURLRequestJob() {
@@ -369,10 +366,15 @@ ExternalFileURLRequestJob::~ExternalFileURLRequestJob() {
 void ExternalFileURLRequestJob::OnReadCompleted(int read_result) {
   DCHECK_CURRENTLY_ON(BrowserThread::IO);
 
-  if (read_result > 0)
-    remaining_bytes_ -= read_result;
+  if (read_result < 0) {
+    DCHECK_NE(read_result, net::ERR_IO_PENDING);
+    NotifyDone(
+        net::URLRequestStatus(net::URLRequestStatus::FAILED, read_result));
+  }
 
-  ReadRawDataComplete(read_result);
+  remaining_bytes_ -= read_result;
+  SetStatus(net::URLRequestStatus());  // Clear the IO_PENDING status.
+  NotifyReadComplete(read_result);
 }
 
 }  // namespace chromeos