Support content scheme uri for Chrome on Android

content/browser/android/url_request_content_job.cc

+// Copyright (c) 2014 The Chromium 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 "content/browser/android/url_request_content_job.h"
+
+#include "base/android/content_uri_utils.h"
+#include "base/bind.h"
+#include "base/files/file_util.h"
+#include "base/message_loop/message_loop.h"
+#include "base/task_runner.h"
+#include "net/base/file_stream.h"
+#include "net/base/io_buffer.h"
+#include "net/base/net_errors.h"
+#include "net/http/http_util.h"
+#include "net/url_request/url_request_error_job.h"
+#include "url/gurl.h"
+
+namespace content {
+
+// TODO(qinmin): Refactor this class to reuse the common code in
+// url_request_file_job.cc.
+URLRequestContentJob::ContentMetaInfo::ContentMetaInfo()
+    : content_exists(false),
+      content_size(0) {
+}
+
+URLRequestContentJob::URLRequestContentJob(
+    net::URLRequest* request,
+    net::NetworkDelegate* network_delegate,
+    const base::FilePath& content_path,
+    const scoped_refptr<base::TaskRunner>& content_task_runner)
+    : net::URLRequestJob(request, network_delegate),
+      content_path_(content_path),
+      stream_(new net::FileStream(content_task_runner)),
+      content_task_runner_(content_task_runner),
+      remaining_bytes_(0),
+      weak_ptr_factory_(this) {}
+
+void URLRequestContentJob::Start() {
+  ContentMetaInfo* meta_info = new ContentMetaInfo();
+  content_task_runner_->PostTaskAndReply(

[no sievers, 2014/11/25 20:50:18]

nit: Why do you want DidFetchMetaInfo to run as a separate task?

[qinmin, 2014/11/25 23:37:02]

FetchMetaInfo() runs on the content_task_runner and DidFetchMetaInfo() runs on
the io thread. I think it is ok to combine DidFetchMetaInfo with some of the
other functions, or post a task back from the content_task_runner when
FetchMetaInfo completes, but here i just want to keep the code similar to that
of the FileRequestContentJob, so we can do some refactoring later.

+      FROM_HERE,
+      base::Bind(&URLRequestContentJob::FetchMetaInfo, content_path_,
+                 base::Unretained(meta_info)),
+      base::Bind(&URLRequestContentJob::DidFetchMetaInfo,
+                 weak_ptr_factory_.GetWeakPtr(),
+                 base::Owned(meta_info)));
+}
+
+void URLRequestContentJob::Kill() {
+  stream_.reset();
+  weak_ptr_factory_.InvalidateWeakPtrs();
+
+  net::URLRequestJob::Kill();
+}
+
+bool URLRequestContentJob::ReadRawData(net::IOBuffer* dest,
+                                       int dest_size,
+                                       int* bytes_read) {
+  DCHECK_NE(dest_size, 0);

[no sievers, 2014/11/25 20:50:18]

DCHECK_GT?

[qinmin, 2014/11/25 23:37:02]

Done.

+  DCHECK(bytes_read);
+  DCHECK_GE(remaining_bytes_, 0);
+
+  if (remaining_bytes_ < dest_size)
+    dest_size = static_cast<int>(remaining_bytes_);
+
+  // If we should copy zero bytes because |remaining_bytes_| is zero, short
+  // circuit here.
+  if (!dest_size) {
+    *bytes_read = 0;
+    return true;
+  }
+
+  int rv = stream_->Read(dest,
+                         dest_size,
+                         base::Bind(&URLRequestContentJob::DidRead,
+                                    weak_ptr_factory_.GetWeakPtr(),
+                                    make_scoped_refptr(dest)));
+  if (rv >= 0) {
+    // Data is immediately available.
+    *bytes_read = rv;
+    remaining_bytes_ -= rv;
+    DCHECK_GE(remaining_bytes_, 0);

[no sievers, 2014/11/25 20:50:18]

I don't see this being implemented in FileStream. Would you mind adding a
|io_pending_| flag and DCHECKing and resetting that in DidRead()?

[qinmin, 2014/11/25 23:37:02]

Done.

+    return true;
+  }
+
+  // Otherwise, a read error occured.  We may just need to wait...
+  if (rv == net::ERR_IO_PENDING) {
+    SetStatus(net::URLRequestStatus(net::URLRequestStatus::IO_PENDING, 0));
+  } else {
+    NotifyDone(net::URLRequestStatus(net::URLRequestStatus::FAILED, rv));
+  }
+  return false;
+}
+
+bool URLRequestContentJob::IsRedirectResponse(GURL* location,
+                                              int* http_status_code) {
+  return false;
+}
+
+bool URLRequestContentJob::GetMimeType(std::string* mime_type) const {
+  DCHECK(request_);
+  if (!meta_info_.mime_type.empty()) {
+    *mime_type = meta_info_.mime_type;
+    return true;
+  }
+  return false;
+}
+
+void URLRequestContentJob::SetExtraRequestHeaders(
+    const net::HttpRequestHeaders& headers) {
+  std::string range_header;
+  if (!headers.GetHeader(net::HttpRequestHeaders::kRange, &range_header))
+    return;
+
+  // We only care about "Range" header here.
+  std::vector<net::HttpByteRange> ranges;
+  if (net::HttpUtil::ParseRangeHeader(range_header, &ranges)) {
+    if (ranges.size() == 1) {
+      byte_range_ = ranges[0];
+    } else {
+      // We don't support multiple range requests.
+      NotifyDone(net::URLRequestStatus(
+          net::URLRequestStatus::FAILED,
+          net::ERR_REQUEST_RANGE_NOT_SATISFIABLE));
+    }
+  }
+}
+
+URLRequestContentJob::~URLRequestContentJob() {}
+
+void URLRequestContentJob::FetchMetaInfo(const base::FilePath& content_path,
+                                         ContentMetaInfo* meta_info) {
+  base::File::Info file_info;
+  meta_info->content_exists = base::GetFileInfo(content_path, &file_info);
+  if (meta_info->content_exists) {
+    meta_info->content_size = file_info.size;
+    meta_info->mime_type = base::GetContentUriMimeType(content_path);
+  }
+}
+
+void URLRequestContentJob::DidFetchMetaInfo(const ContentMetaInfo* meta_info) {
+  meta_info_ = *meta_info;
+
+  if (!meta_info_.content_exists) {
+    DidOpen(net::ERR_FILE_NOT_FOUND);
+    return;
+  }
+
+  int flags = base::File::FLAG_OPEN |
+              base::File::FLAG_READ |
+              base::File::FLAG_ASYNC;
+  int rv = stream_->Open(content_path_, flags,
+                         base::Bind(&URLRequestContentJob::DidOpen,
+                                    weak_ptr_factory_.GetWeakPtr()));
+  if (rv != net::ERR_IO_PENDING)
+    DidOpen(rv);
+}
+
+void URLRequestContentJob::DidOpen(int result) {
+  if (result != net::OK) {
+    NotifyDone(net::URLRequestStatus(net::URLRequestStatus::FAILED, result));
+    return;
+  }
+
+  if (!byte_range_.ComputeBounds(meta_info_.content_size)) {
+    NotifyDone(net::URLRequestStatus(net::URLRequestStatus::FAILED,
+                                     net::ERR_REQUEST_RANGE_NOT_SATISFIABLE));
+    return;
+  }
+
+  remaining_bytes_ = byte_range_.last_byte_position() -
+                     byte_range_.first_byte_position() + 1;
+  DCHECK_GE(remaining_bytes_, 0);
+
+  if (remaining_bytes_ > 0 && byte_range_.first_byte_position() != 0) {
+    int rv = stream_->Seek(base::File::FROM_BEGIN,
+                           byte_range_.first_byte_position(),
+                           base::Bind(&URLRequestContentJob::DidSeek,
+                                      weak_ptr_factory_.GetWeakPtr()));
+    if (rv != net::ERR_IO_PENDING) {
+      // stream_->Seek() failed, so pass an intentionally erroneous value
+      // into DidSeek().
+      DidSeek(-1);
+    }
+  } else {
+    // We didn't need to call stream_->Seek() at all, so we pass to DidSeek()
+    // the value that would mean seek success. This way we skip the code
+    // handling seek failure.
+    DidSeek(byte_range_.first_byte_position());
+  }
+}
+
+void URLRequestContentJob::DidSeek(int64 result) {
+  if (result != byte_range_.first_byte_position()) {
+    NotifyDone(net::URLRequestStatus(net::URLRequestStatus::FAILED,
+                                     net::ERR_REQUEST_RANGE_NOT_SATISFIABLE));
+    return;
+  }
+
+  set_expected_content_size(remaining_bytes_);
+  NotifyHeadersComplete();
+}
+
+void URLRequestContentJob::DidRead(
+    scoped_refptr<net::IOBuffer> buf, int result) {
+  if (result > 0) {
+    SetStatus(net::URLRequestStatus());  // Clear the IO_PENDING status
+    remaining_bytes_ -= result;
+    DCHECK_GE(remaining_bytes_, 0);
+  }
+
+  buf = NULL;

[no sievers, 2014/11/25 20:50:18]

Either remove this or put a comment why this needs to be done before calling
Notify*().

[qinmin, 2014/11/25 23:37:02]

removed.

+
+  if (result == 0) {

[no sievers, 2014/11/25 20:50:18]

why not 'if (result >= 0)'?

[qinmin, 2014/11/25 23:37:02]

all errors have negative value, and non-failure case the return value is 0.
added a DCHECK.

[no sievers, 2014/11/25 23:51:52]

But above you are handling |result > 0|.

[qinmin, 2014/11/26 00:56:46]

ah... if resule>=0, the return value is the size read by file_stream. So in this
case, it means read hasn't completed yet, and we shouldn't call NotifyDone. If
result == 0, it means read has completed, and we can call NotifyDone. If result
< 0, an error is encounterde..

[no sievers, 2014/11/26 01:09:49]

So DidRead() gets called twice, once with result == bytes_read and then with
result == 0?
I only see it post the completion callback once from
FileStream::Context::Read().

[qinmin, 2014/11/26 01:38:42]

The actual implementation should be in file_stream_context_posix.cc, if you
check FileStream::Context::ReadFileImpl(), you can see that the returned result
is defined in unistd.h, 0 for EOF, bytes read for successful case, and -1 for
error.

[no sievers, 2014/11/26 01:46:08]

Ok as long as it works fine and we end up calling NotifyDone() if the size of
the read request is exactly equal to the remaining bytes in the file.

+    NotifyDone(net::URLRequestStatus());
+  } else if (result < 0) {
+    NotifyDone(net::URLRequestStatus(net::URLRequestStatus::FAILED, result));
+  }
+
+  NotifyReadComplete(result);

[no sievers, 2014/11/25 20:50:18]

Does the order of NotifyDone and NotifyReadComplete matter?

[qinmin, 2014/11/25 23:37:02]

I think the ordering shouldn't matter as NotifyDone actually post a task. I
simply kept the ordering from URLRequestFileJob.

+}
+
+}  // namespace content