Add ModuleInspector

chrome/browser/conflicts/module_inspector_win.h

+// Copyright 2017 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.
+
+#ifndef CHROME_BROWSER_CONFLICTS_MODULE_INSPECTOR_WIN_H_
+#define CHROME_BROWSER_CONFLICTS_MODULE_INSPECTOR_WIN_H_
+
+#include <memory>
+#include <queue>
+
+#include "base/callback.h"
+#include "base/macros.h"
+#include "base/memory/weak_ptr.h"
+#include "base/task_scheduler/task_traits.h"
+#include "base/threading/thread_checker.h"
+#include "chrome/browser/conflicts/module_info_win.h"
+
+// This class takes care of inspecting several modules (identified by their
+// ModuleInfoKey) and returning the result via the OnModuleInspectedCallback on
+// the SequencedTaskRunner where it was created.
+//
+// The inspection of all modules is quite expensive in terms of resources, so it
+// is done one by one, in a task with a background priority level. If needed, it
+// is possible to increase the priority level of these tasks by calling
+// IncreaseInspectionPriority().
+//
+// This class is not thread safe and it enforces safety via a ThreadChecker.
+class ModuleInspector {
+ public:
+  using OnModuleInspectedCallback =
+      base::Callback<void(const ModuleInfoKey& module_key,
+                          std::unique_ptr<ModuleInspectionResult>)>;
+
+  explicit ModuleInspector(
+      const OnModuleInspectedCallback& on_module_inspected_callback);
+  ~ModuleInspector();
+
+  // Adds the module to the queue of modules to inspect. Starts the inspection
+  // process if the |queue_| is empty.
+  void AddModule(const ModuleInfoKey& module_key);
+
+  // Removes the throttling.
+  void IncreaseInspectionPriority();
+
+ private:
+  // Starts inspecting the module at the front of the queue.
+  void StartInspectingModule();
+
+  // Called back on the execution context on which the ModuleInspector was
+  // created when a module has finished being inspected. The callback will be
+  // executed and, if the |queue_| is not empty, the next module will be sent
+  // for inspection.
+  void OnInspectionFinished(
+      const ModuleInfoKey& module_key,
+      std::unique_ptr<ModuleInspectionResult> inspection_result);
+
+  OnModuleInspectedCallback on_module_inspected_callback_;
+
+  // The modules are put in queue until they are sent for inspection.
+  std::queue<ModuleInfoKey> queue_;
+
+  // The traits used on the task that inspects the modules. It originally starts
+  // at a BACKGROUND priority, but is changed to USER_VISIBLE when
+  // IncreaseInspectionPriority() is called.
+  base::TaskTraits inspection_task_traits_;
+
+  // The vector of paths to %env_var%, used to account for differences in
+  // localization and where people keep their files.
+  // e.g. c:\windows vs d:\windows
+  StringMapping path_mapping_;
+
+  base::ThreadChecker thread_checker_;
+
+  // Weak pointers are used to safely post the inspection result back to the
+  // ModuleInspector from the task scheduler.
+  base::WeakPtrFactory<ModuleInspector> weak_ptr_factory_;
+
+  DISALLOW_COPY_AND_ASSIGN(ModuleInspector);
+};
+
+#endif  // CHROME_BROWSER_CONFLICTS_MODULE_INSPECTOR_WIN_H_