Component updater second installment

introducing the main external objects:
-ComponentInstaller
-ComponentUpdateService

The ComponentUnpacker is an implementation detail but it
is fairly simple and we might as well deal with it.

Tests are comming with the next CL.

TEST=none
BUG=61602
Review URL: http://codereview.chromium.org/7458011

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@93530 0039d316-1c4b-4281-b951-d872f2087c98

1 files changed, 125 insertions, 0 deletions

diff --git a/chrome/browser/component_updater/component_updater_service.h b/chrome/browser/component_updater/component_updater_service.h
new file mode 100644
index 0000000..9e55a33
--- /dev/null
+++ b/chrome/browser/component_updater/component_updater_service.h
@@ -0,0 +1,125 @@
+// Copyright (c) 2011 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_COMPONENT_UPDATER_COMPONENT_UPDATER_SERVICE_H_
+#define CHROME_BROWSER_COMPONENT_UPDATER_COMPONENT_UPDATER_SERVICE_H_
+#pragma once
+
+#include <string>
+#include <vector>
+
+#include "base/version.h"
+#include "googleurl/src/gurl.h"
+
+class FilePath;
+
+namespace net {
+class URLRequestContextGetter;
+}
+
+namespace base {
+class DictionaryValue;
+}
+
+// Component specific installers must derive from this class and implement
+// OnUpdateError() and Install(). A valid instance of this class must be
+// given to ComponentUpdateService::RegisterComponent().
+class ComponentInstaller {
+ public :
+  virtual ~ComponentInstaller() {}
+
+  // Called by the component updater on the UI thread when there was a
+  // problem unpacking or verifying the component. |error| is a non-zero
+  // value which is only meaninful to the component updater.
+  virtual void OnUpdateError(int error) = 0;
+
+  // Called by the component updater when a component has been unpacked
+  // and is ready to be installed. |manifest| contains the CRX manifest
+  // json dictionary and |unpack_path| contains the temporary directory
+  // with all the unpacked CRX files.
+  virtual bool Install(base::DictionaryValue* manifest,
+                       const FilePath& unpack_path) = 0;
+};
+
+// Describes a particular component that can be installed or updated. This
+// structure is required to register a component with the component updater.
+// Only |name| is optional. |pk_hash| is the SHA256 hash of the component's
+// public key. If the component is to be installed then version should be
+// "0" or "0.0", else it should be the current version.
+struct CrxComponent {
+  std::vector<uint8> pk_hash;
+  ComponentInstaller* installer;
+  Version version;
+  std::string name;
+  CrxComponent();
+  ~CrxComponent();
+};
+
+// The component update service is in charge of installing or upgrading
+// select parts of chrome. Each part is called a component and managed by
+// instances of CrxComponent registered using RegisterComponent(). On the
+// server, each component is packaged as a CRX which is the same format used
+// to package extensions. To the update service each component is identified
+// by its public key hash (CrxComponent::pk_hash). If there is an update
+// available and its version is bigger than (CrxComponent::version), it will
+// be downloaded, verified and unpacked. Then component-specific installer
+// ComponentInstaller::Install (of CrxComponent::installer) will be called.
+//
+// During the normal operation of the component updater some specific
+// notifications are fired, like COMPONENT_UPDATER_STARTED and
+// COMPONENT_UPDATE_FOUND. See notification_type.h for more details.
+//
+// All methods are safe to call ONLY from chrome's UI thread.
+class ComponentUpdateService {
+ public:
+  enum Status {
+    kOk,
+    kReplaced,
+    kError
+  };
+  // Controls the component updater behavior.
+  class Configurator {
+   public:
+    virtual ~Configurator() {}
+    // Delay in seconds from calling Start() to the first update check.
+    virtual int InitialDelay() = 0;
+    // Delay in seconds to every subsequent update check. 0 means don't check.
+    virtual int NextCheckDelay() = 0;
+    // Delay in seconds from each task step. Used to smooth out CPU/IO usage.
+    virtual int StepDelay() = 0;
+    // The url that is going to be used update checks over Omaha protocol.
+    virtual GURL UpdateUrl() = 0;
+    // How big each update request can be. Don't go above 2000.
+    virtual size_t UrlSizeLimit() = 0;
+    // The source of contexts for all the url requests.
+    virtual net::URLRequestContextGetter* RequestContext() = 0;
+    // True means that all ops are peformed in this process.
+    virtual bool InProcess() = 0;
+  };
+
+  // Start doing update checks and installing new versions of registered
+  // components after Configurator::InitialDelay() seconds.
+  virtual Status Start() = 0;
+
+  // Stop doing update checks. In-flight requests and pending installations
+  // will not be cancelled.
+  virtual Status Stop() = 0;
+
+  // Add component to be checked for updates. You can call this method
+  // before calling Start().
+  virtual Status RegisterComponent(const CrxComponent& component) = 0;
+
+ protected:
+  virtual ~ComponentUpdateService() {}
+};
+
+// Creates the component updater. Pass NULL in |config| to use the default
+// configuration. Only the first caller can specify a configuration; on
+// subsequent calls it will be ignored and the current instance of the
+// component updater will be used.
+ComponentUpdateService* ComponentUpdateServiceFactory(
+    ComponentUpdateService::Configurator* config);
+
+#endif  // CHROME_BROWSER_COMPONENT_UPDATER_COMPONENT_UPDATER_SERVICE_H_
+