Upstream Android JNI code, allowing us to use more ScopedJava references.

base/android/jni_android.h

 // 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 BASE_ANDROID_JNI_ANDROID_H_
 #define BASE_ANDROID_JNI_ANDROID_H_
 
 #include <jni.h>
 #include <sys/types.h>
 
 #include "base/android/scoped_java_ref.h"
 
 namespace base {
 namespace android {
 
 // Attach the current thread to the VM (if necessary) and return the JNIEnv*.
 JNIEnv* AttachCurrentThread();
 
 // Detach the current thread from VM if it is attached.
 void DetachFromVM();
 
 // Initializes the global JVM. It is not necessarily called before
 // InitApplicationContext().
 void InitVM(JavaVM* vm);
 
 // Initializes the global application context object. The |context| can be any
 // valid reference to the application context. Internally holds a global ref to
 // the context. InitVM and InitApplicationContext maybe called in either order.
-// TODO: We might combine InitVM() and InitApplicationContext() into one method.
 void InitApplicationContext(const JavaRef<jobject>& context);
 
 // Gets a global ref to the application context set with
 // InitApplicationContext(). Ownership is retained by the function - the caller
 // must NOT release it.
-jobject GetApplicationContext();
+const jobject GetApplicationContext();
+
+// Finds the class named |class_name| and returns it.
+// Use this method instead of invoking directly the JNI FindClass method (to
+// prevent leaking local references).
+// This method triggers a fatal assertion if the class could not be found.
+// Use HasClass if you need to check whether the class exists.
+ScopedJavaLocalRef<jclass> GetClass(JNIEnv* env, const char* class_name);
+
+// Returns true iff the class |class_name| could be found.
+bool HasClass(JNIEnv* env, const char* class_name);
+
+// Returns the method ID for the method with the specified name and signature.
+// This method triggers a fatal assertion if the method could not be found.
+// Use HasMethod if you need to check whether a method exists.
+jmethodID GetMethodID(JNIEnv* env,
+                      const JavaRef<jclass>& clazz,
+                      const char* method_name,
+                      const char* jni_signature);
+
+// Returns the method ID for the static method with the specified name and
+// signature.
+// This method triggers a fatal assertion if the method could not be found.
+// Use HasMethod if you need to check whether a method exists.
+jmethodID GetStaticMethodID(JNIEnv* env,
+                            const JavaRef<jclass>& clazz,
+                            const char* method_name,
+                            const char* jni_signature);
+
+// Returns true iff |clazz| has a method with the specified name and signature.
+bool HasMethod(JNIEnv* env,
+               const JavaRef<jclass>& clazz,
+               const char* method_name,
+               const char* jni_signature);
 
 // Gets the method ID from the class name. Clears the pending Java exception
 // and returns NULL if the method is not found. Caches results. Note that
 // GetMethodID() below avoids a class lookup, but does not cache results.
 // Strings passed to this function are held in the cache and MUST remain valid
 // beyond the duration of all future calls to this function, across all
 // threads. In practice, this means that the function should only be used with
 // string constants.
 jmethodID GetMethodIDFromClassName(JNIEnv* env,
                                    const char* class_name,
                                    const char* method,
                                    const char* jni_signature);
 
-// Get the method ID for a method. Will clear the pending Java
-// exception and return 0 if the method is not found.
-jmethodID GetMethodID(JNIEnv* env,
-                      jclass clazz,
-                      const char* const method,
-                      const char* const jni_signature);
-
-// Get the method ID for a class static method. Will clear the pending Java
-// exception and return 0 if the method is not found.
-jmethodID GetStaticMethodID(JNIEnv* env,
-                            jclass clazz,
-                            const char* const method,
-                            const char* const jni_signature);
-
-// Gets the field ID for a class field. Clears the pending Java exception and
-// returns NULL if the field is not found.
+// Gets the field ID for a class field.
+// This method triggers a fatal assertion if the field could not be found.
 jfieldID GetFieldID(JNIEnv* env,
-                    jclass clazz,
-                    const char* field,
+                    const JavaRef<jclass>& clazz,
+                    const char* field_name,
                     const char* jni_signature);
 
-// Returns true if an exception is pending in the provided JNIEnv*. If an
-// exception is pending, this function prints and then clears it.
-bool CheckException(JNIEnv* env);
+// Returns true if |clazz| as a field with the given name and signature.
+// TODO(jcivelli): Determine whether we explicitly have to pass the environment.
+bool HasField(JNIEnv* env,
+              const JavaRef<jclass>& clazz,
+              const char* field_name,
+              const char* jni_signature);
+
+// Gets the field ID for a static class field.
+// This method triggers a fatal assertion if the field could not be found.
+jfieldID GetStaticFieldID(JNIEnv* env,
+                          const JavaRef<jclass>& clazz,
+                          const char* field_name,
+                          const char* jni_signature);
+
+// Returns true if an exception is pending in the provided JNIEnv*.
+bool HasException(JNIEnv* env);
+
+// If an exception is pending in the provided JNIEnv*, this function clears it
+// and returns true.
+bool ClearException(JNIEnv* env);
+
+// This function will call CHECK() macro if there's any pending exception.
+void CheckException(JNIEnv* env);
 
 }  // namespace android
 }  // namespace base
 
 #endif  // BASE_ANDROID_JNI_ANDROID_H_