content/browser/renderer_host/java/java_bound_object.h

   1 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 #ifndef CONTENT_BROWSER_RENDERER_HOST_JAVA_JAVA_BOUND_OBJECT_H_
   6 #define CONTENT_BROWSER_RENDERER_HOST_JAVA_JAVA_BOUND_OBJECT_H_
   7
   8 #include <jni.h>
   9 #include <map>
  10 #include <string>
  11
  12 #include "base/android/jni_helper.h"
  13 #include "base/android/scoped_java_ref.h"
  14 #include "base/memory/linked_ptr.h"
  15 #include "base/memory/weak_ptr.h"
  16 #include "content/browser/renderer_host/java/java_method.h"
  17 #include "third_party/npapi/bindings/npruntime.h"
  18
  19 namespace content {
  20
  21 class JavaBridgeDispatcherHostManager;
  22
  23 // Wrapper around a Java object.
  24 //
  25 // Represents a Java object for use in the Java bridge. Holds a global ref to
  26 // the Java object and provides the ability to invoke methods on it.
  27 // Interrogation of the Java object for its methods is done lazily. This class
  28 // is not generally threadsafe. However, it does allow for instances to be
  29 // created and destroyed on different threads.
  30 class JavaBoundObject {
  31  public:
  32   // Takes a Java object and creates a JavaBoundObject around it. If
  33   // |safe_annotation_clazz| annotation is non-null, the method is exposed
  34   // to JavaScript. Returns an NPObject with a ref count of one which owns the
  35   // JavaBoundObject.
  36   // See also comment below for |manager_|.
  37   static NPObject* Create(
  38       const base::android::JavaRef<jobject>& object,
  39       const base::android::JavaRef<jclass>& safe_annotation_clazz,
  40       const base::WeakPtr<JavaBridgeDispatcherHostManager>& manager);
  41
  42   virtual ~JavaBoundObject();
  43
  44   // Gets a local ref to the underlying JavaObject from a JavaBoundObject
  45   // wrapped as an NPObject. May return null if the underlying object has
  46   // been garbage collected.
  47   static base::android::ScopedJavaLocalRef<jobject> GetJavaObject(
  48       NPObject* object);
  49
  50   // Methods to implement the NPObject callbacks.
  51   bool HasMethod(const std::string& name) const;
  52   bool Invoke(const std::string& name, const NPVariant* args, size_t arg_count,
  53               NPVariant* result);
  54
  55  private:
  56   explicit JavaBoundObject(
  57       const base::android::JavaRef<jobject>& object,
  58       const base::android::JavaRef<jclass>& safe_annotation_clazz,
  59       const base::WeakPtr<JavaBridgeDispatcherHostManager>& manager_);
  60
  61   void EnsureMethodsAreSetUp() const;
  62
  63   // The weak ref to the underlying Java object that this JavaBoundObject
  64   // instance represents.
  65   JavaObjectWeakGlobalRef java_object_;
  66
  67   // Keep a pointer back to the JavaBridgeDispatcherHostManager so that we
  68   // can notify it when this JavaBoundObject is destroyed. JavaBoundObjects
  69   // may outlive the manager so keep a WeakPtr. Note the WeakPtr may only be
  70   // dereferenced on the UI thread.
  71   base::WeakPtr<JavaBridgeDispatcherHostManager> manager_;
  72
  73   // Map of public methods, from method name to Method instance. Multiple
  74   // entries will be present for overloaded methods. Note that we can't use
  75   // scoped_ptr in STL containers as we can't copy it.
  76   typedef std::multimap<std::string, linked_ptr<JavaMethod> > JavaMethodMap;
  77   mutable JavaMethodMap methods_;
  78   mutable bool are_methods_set_up_;
  79
  80   base::android::ScopedJavaGlobalRef<jclass> safe_annotation_clazz_;
  81
  82   DISALLOW_IMPLICIT_CONSTRUCTORS(JavaBoundObject);
  83 };
  84
  85 }  // namespace content
  86
  87 #endif  // CONTENT_BROWSER_RENDERER_HOST_JAVA_JAVA_BOUND_OBJECT_H_