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 <stdio.h>

[mmenke, 2013/01/18 15:58:00]

Is this needed?  We use FILE*'s, but no stdio functions.

[ramant (doing other things), 2013/01/18 23:22:33]

Done.

+
+#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"
+
+namespace {
+
+bool GetNetExportDir(const FilePath::StringType& chrome_net_export,
+                     FilePath* path) {
+  // We will try to create chrome_net_export (or make sure chrome_net_export
+  // directory exists) directory twice in file_util::GetTempDir.
+  for (int i = 0; i < 2; ++i) {
+    FilePath temp_dir;
+    if (!file_util::GetTempDir(&temp_dir))
+      continue;
+
+    FilePath net_export_dir = temp_dir.Append(chrome_net_export);
+    if (file_util::PathExists(net_export_dir)) {
+      *path = net_export_dir;
+      return true;
+    }
+
+    if (!file_util::CreateDirectory(net_export_dir))
+      continue;
+
+    *path = net_export_dir;
+    return true;
+  }
+
+  return false;
+}
+
+bool GetNetExportLog(const FilePath::StringType& chrome_net_export,
+                     const FilePath::StringType& log_filename,
+                     FilePath* path) {
+  FilePath net_export_dir;
+  if (!GetNetExportDir(chrome_net_export, &net_export_dir))
+    return false;
+
+  *path = net_export_dir.Append(log_filename);
+  return true;
+}
+
+}  // namespace
+
+NetLogTempFile::NetLogTempFile(ChromeNetLog* chrome_net_log)
+    : state_(STATE_UNINITIALIZED),
+      chrome_net_export_(FILE_PATH_LITERAL("chrome-net-export")),
+      log_filename_(FILE_PATH_LITERAL("log.json")),

[mmenke, 2013/01/18 15:58:00]

Don't think a pathname + a file name really gets us anything, at the moment. 
Suggest just calling it chrome-net-export-log.json to simplify things.  My main
concern is just leaving stuff on the build bots, and having the test fixture
complain, but also simplifies life a little.

[ramant (doing other things), 2013/01/18 23:22:33]

Done.

+      chrome_net_log_(chrome_net_log) {
+}
+
+NetLogTempFile::~NetLogTempFile() {
+  if (net_log_logger_.get())
+    net_log_logger_->StopObserving();
+}
+
+void NetLogTempFile::ProcessCommand(Command command) {
+  // Determine the state_ if it is not set.
+  if (state_ == STATE_UNINITIALIZED)
+    Init();
+
+  switch (command) {
+    case DO_START:
+      StartNetLog();
+      break;
+    case DO_STOP:
+      StopNetLog();
+      break;
+    default:
+      break;
+  }
+}
+
+DictionaryValue* NetLogTempFile::GetState() {
+  // Determine the state_ if it is not set.
+  if (state_ == STATE_UNINITIALIZED)
+    Init();
+
+  base::DictionaryValue* dict = new base::DictionaryValue;
+
+#ifndef NDEBUG
+  dict->SetString("file", log_path_.MaybeAsASCII());
+#endif  // NDEBUG
+
+  switch (state_) {
+    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;
+}
+
+void NetLogTempFile::Init() {
+  if (state_ != STATE_UNINITIALIZED)
+    return;
+
+  FilePath net_export_log;
+  if (!GetNetExportLog(chrome_net_export_, log_filename_, &net_export_log)) {
+    state_ = STATE_ALLOW_START;
+    return;
+  }
+
+  log_path_ = net_export_log;
+  if (file_util::PathExists(log_path_))
+    state_ = STATE_ALLOW_START_SEND;
+  else
+    state_ = STATE_ALLOW_START;
+}
+
+void NetLogTempFile::StartNetLog() {
+  if (state_ == STATE_ALLOW_STOP)
+    return;
+
+  // Call GetNetExportLog to make sure |chrome_net_export_| is created in
+  // file_util::GetTempDir (in case the temporary directory is deleted by the
+  // time user clicks on START button).
+  FilePath net_export_log;
+  if (!GetNetExportLog(chrome_net_export_, log_filename_, &net_export_log))
+    return;
+
+  // Try to make sure we can create the file.
+  FILE* fp = file_util::OpenFile(net_export_log, "w");

[mmenke, 2013/01/18 15:58:00]

Fine for now, but I'd like to look into a better way of doing this.

[ramant (doing other things), 2013/01/18 23:22:33]

Added a TODO.

+  if (!fp) {
+    LOG(ERROR) << "Could not open file " << net_export_log.value()
+               << " for net logging";
+    return;
+  } else {
+      file_util::CloseFile(fp);

[mmenke, 2013/01/18 15:58:00]

nit:  Fix indent.

[ramant (doing other things), 2013/01/18 23:22:33]

Done.

+  }
+
+  log_path_ = net_export_log;
+  net_log_logger_.reset(new NetLogLogger(log_path_));
+  net_log_logger_->StartObserving(chrome_net_log_);
+  state_ = STATE_ALLOW_STOP;
+}
+
+void NetLogTempFile::StopNetLog() {
+  if (state_ != STATE_ALLOW_STOP)
+    return;
+
+  net_log_logger_->StopObserving();
+  net_log_logger_.reset();
+  state_ = STATE_ALLOW_START_SEND;
+}
+
+bool NetLogTempFile::GetFilePath(FilePath* path) {
+  if (state_ != STATE_ALLOW_START_SEND)
+    return false;
+
+  FilePath net_export_log;
+  if (!GetNetExportLog(chrome_net_export_, log_filename_, &net_export_log))
+    return false;
+
+  if (!file_util::PathExists(net_export_log))
+    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(net_export_log, mode);
+#endif  // defined(OS_POSIX)
+
+  *path = net_export_log;
+  return true;
+}