First cut at UI for saving net_logs data into a temporary file on

chrome/browser/net/net_log_temp_file.cc

+// Copyright (c) 2013 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 "chrome/browser/net/net_log_temp_file.h"
+
+#include "base/file_util.h"
+#include "base/values.h"
+#include "chrome/browser/net/chrome_net_log.h"
+#include "chrome/browser/net/net_log_logger.h"
+#include "content/public/browser/browser_thread.h"
+
+using content::BrowserThread;
+
+NetLogTempFile::NetLogTempFile(ChromeNetLog* chrome_net_log)
+    : state_(STATE_UNINITIALIZED),
+      log_filename_(FILE_PATH_LITERAL("chrome-net-export-log.json")),
+      chrome_net_log_(chrome_net_log) {
+}
+
+NetLogTempFile::~NetLogTempFile() {
+  if (net_log_logger_.get())
+    net_log_logger_->StopObserving();
+}
+
+void NetLogTempFile::ProcessCommand(Command command) {
+  DCHECK(BrowserThread::CurrentlyOn(BrowserThread::FILE_USER_BLOCKING));
+  // Determine the state_ if it is not set.
+  if (!Init())

[mmenke, 2013/01/25 17:39:12]

Suggest renaming this to "EnsureInit()" to better reflect the new behavior.

With this change, think we can remove the "Determine the state_ if it is not
set." comments wherever they appear, too.

[ramant (doing other things), 2013/01/25 20:05:24]

Done.

+    return;
+
+  switch (command) {
+    case DO_START:
+      StartNetLog();
+      break;
+    case DO_STOP:
+      StopNetLog();
+      break;
+    default:
+      break;
+  }
+}
+
+DictionaryValue* NetLogTempFile::GetState() {
+  DCHECK(BrowserThread::CurrentlyOn(BrowserThread::FILE_USER_BLOCKING));
+  base::DictionaryValue* dict = new base::DictionaryValue;
+
+  // Determine the state_ if it is not set.
+  if (!Init())
+    return dict;
+
+#ifndef NDEBUG
+  dict->SetString("file", log_path_.LossyDisplayName());
+#endif  // NDEBUG
+
+  switch (state_) {

[mmenke, 2013/01/25 17:39:12]

Think we should always return a state, even when Init() fails, and then display
some sort of error on the page.  Don't think this is likely to happen, but think
it's worth displaying something when it does.

[ramant (doing other things), 2013/01/25 20:05:24]

Done.

+    case STATE_ALLOW_STOP:
+      dict->SetString("state", "ALLOW_STOP");
+      break;
+    case STATE_ALLOW_START_SEND:
+      dict->SetString("state", "ALLOW_START_SEND");
+      break;
+    default:
+      dict->SetString("state", "ALLOW_START");
+      break;
+  }
+  return dict;
+}
+
+bool NetLogTempFile::Init() {
+  DCHECK(BrowserThread::CurrentlyOn(BrowserThread::FILE_USER_BLOCKING));
+  if (state_ != STATE_UNINITIALIZED)
+    return true;
+
+  if (!GetNetExportLog())
+    return false;
+
+  if (NetExportLogExists())
+    state_ = STATE_ALLOW_START_SEND;
+  else
+    state_ = STATE_ALLOW_START;
+
+  return true;
+}
+
+void NetLogTempFile::StartNetLog() {
+  DCHECK(BrowserThread::CurrentlyOn(BrowserThread::FILE_USER_BLOCKING));
+  if (state_ == STATE_ALLOW_STOP)
+    return;
+
+  DCHECK_NE(state_, STATE_UNINITIALIZED);
+  DCHECK(!log_path_.empty());
+
+  // Try to make sure we can create the file.
+  // TODO(rtenneti): Find a better for doing the following.
+  FILE* fp = file_util::OpenFile(log_path_, "w");
+  if (!fp)

[mmenke, 2013/01/25 17:39:12]

Wonder if we should surface some error to the user in this case.  Not worth
worrying about in this CL.

[ramant (doing other things), 2013/01/25 20:05:24]

Added this to TODO.

+    return;
+  file_util::CloseFile(fp);
+
+  net_log_logger_.reset(new NetLogLogger(log_path_));
+  net_log_logger_->StartObserving(chrome_net_log_);
+  state_ = STATE_ALLOW_STOP;
+}
+
+void NetLogTempFile::StopNetLog() {
+  DCHECK(BrowserThread::CurrentlyOn(BrowserThread::FILE_USER_BLOCKING));
+  if (state_ != STATE_ALLOW_STOP)
+    return;
+
+  net_log_logger_->StopObserving();
+  net_log_logger_.reset();
+  state_ = STATE_ALLOW_START_SEND;
+}
+
+bool NetLogTempFile::GetFilePath(FilePath* path) {
+  DCHECK(BrowserThread::CurrentlyOn(BrowserThread::FILE_USER_BLOCKING));
+  if (state_ != STATE_ALLOW_START_SEND)
+    return false;
+
+  if (!NetExportLogExists())
+    return false;
+
+#if defined(OS_POSIX)
+  // Users, group and others can read, write and traverse.
+  int mode = file_util::FILE_PERMISSION_MASK;
+  file_util::SetPosixFilePermissions(log_path_, mode);
+#endif  // defined(OS_POSIX)
+
+  *path = log_path_;
+  return true;
+}
+
+bool NetLogTempFile::GetNetExportLog() {
+  DCHECK(BrowserThread::CurrentlyOn(BrowserThread::FILE_USER_BLOCKING));
+  FilePath temp_dir;
+  if (!GetNetExportLogDirectory(&temp_dir))
+    return false;
+
+  log_path_ = temp_dir.Append(log_filename_);
+  return true;
+}
+
+bool NetLogTempFile::GetNetExportLogDirectory(FilePath* path) {
+  DCHECK(BrowserThread::CurrentlyOn(BrowserThread::FILE_USER_BLOCKING));
+  return file_util::GetTempDir(path);
+}
+
+bool NetLogTempFile::NetExportLogExists() {
+  DCHECK(BrowserThread::CurrentlyOn(BrowserThread::FILE_USER_BLOCKING));
+  return file_util::PathExists(log_path_);
+}