Android: adds Get(Static)MethodIDOrNULL.

base/android/jni_android.cc

 // Copyright (c) 2012 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 "base/android/jni_android.h"
 
 #include <map>
 
 #include "base/android/build_info.h"
 #include "base/android/jni_string.h"
@@ skipping 78 matching lines @@
       printstream.obj());
 
   // Call ByteArrayOutputStream.toString()
   ScopedJavaLocalRef<jstring> exception_string(
       env, static_cast<jstring>(
           env->CallObjectMethod(bytearray_output_stream.obj(),
                                 bytearray_output_stream_tostring)));
 
   return ConvertJavaStringToUTF8(exception_string);
 }
+
+enum MethodType {
+  METHODTYPE_STATIC,
+  METHODTYPE_NORMAL,
+};
+
+enum ExceptionCheck {
+  EXCEPTIIONCHECK_YES,
+  EXCEPTIIONCHECK_NO,
+};
+
+jmethodID GetMethodIDInternal(JNIEnv* env,
+                              jclass clazz,
+                              const char* method_name,
+                              const char* jni_signature,
+                              MethodType method_type,
+                              ExceptionCheck exception_check) {

[joth, 2012/10/01 16:15:27]

for bonus points these enums could be template args.

[bulach, 2012/10/01 17:25:00]

would that make any of this, or the caller code, clearer? :)

[joth, 2012/10/01 17:57:19]

Possibly. It clearly communicates which params we expect (require) to be
compile-time constant; at the moment it's vague and I need to read-around the
code more to work out why we have this. (reading this My brain thought at first
"why do we need 'is static' to be run-time definable? surely we always know for
a given method if it's static or not, this can't change at runtime")

+  jmethodID method_id = method_type == METHODTYPE_STATIC ?
+      env->GetMethodID(clazz, method_name, jni_signature) :
+      env->GetStaticMethodID(clazz, method_name, jni_signature);
+  if (exception_check == EXCEPTIIONCHECK_YES) {
+    CHECK(method_id && base::android::ClearException(env)) <<
+      "Failed to find " <<
+      (method_type == METHODTYPE_STATIC ? " static " : " ") <<

[joth, 2012/10/01 16:15:27]

uber-nit: you don't need the space before 'static' or in the else clause.

[bulach, 2012/10/01 17:25:00]

Done.

+      "method " << method_name << " " << jni_signature;
+  } else if (base::android::HasException(env)) {
+    env->ExceptionClear();
+  }
+  return method_id;
+}
+
 }  // namespace
 
 namespace base {
 namespace android {
 
 JNIEnv* AttachCurrentThread() {
   if (!g_jvm)
     return NULL;
   JNIEnv* env = NULL;
   jint ret = g_jvm->AttachCurrentThread(&env, NULL);
@@ skipping 49 matching lines @@
                       const char* method_name,
                       const char* jni_signature) {
   // clazz.env() can not be used as that may be from a different thread.
   return GetMethodID(env, clazz.obj(), method_name, jni_signature);
 }
 
 jmethodID GetMethodID(JNIEnv* env,
                       jclass clazz,
                       const char* method_name,
                       const char* jni_signature) {
-  jmethodID method_id =
-      env->GetMethodID(clazz, method_name, jni_signature);
-  CHECK(method_id && !ClearException(env)) << "Failed to find method " <<
-      method_name << " " << jni_signature;
-  return method_id;
+  return GetMethodIDInternal(
+      env, clazz, method_name, jni_signature,
+      METHODTYPE_NORMAL, EXCEPTIIONCHECK_YES);
+}
+
+jmethodID GetMethodIDOrNull(JNIEnv* env,
+                            jclass clazz,
+                            const char* method_name,
+                            const char* jni_signature) {
+  return GetMethodIDInternal(
+      env, clazz, method_name, jni_signature,
+      METHODTYPE_NORMAL, EXCEPTIIONCHECK_NO);
 }
 
 jmethodID GetStaticMethodID(JNIEnv* env,
                             const JavaRef<jclass>& clazz,
                             const char* method_name,
                             const char* jni_signature) {
   return GetStaticMethodID(env, clazz.obj(), method_name,
       jni_signature);
 }
 
 jmethodID GetStaticMethodID(JNIEnv* env,
                             jclass clazz,
                             const char* method_name,
                             const char* jni_signature) {
-  jmethodID method_id =
-      env->GetStaticMethodID(clazz, method_name, jni_signature);
-  CHECK(method_id && !ClearException(env)) << "Failed to find static method " <<
-      method_name << " " << jni_signature;
-  return method_id;
+  return GetMethodIDInternal(
+      env, clazz, method_name, jni_signature,
+      METHODTYPE_STATIC, EXCEPTIIONCHECK_YES);
+}
+
+jmethodID GetStaticMethodIDOrNull(JNIEnv* env,
+                                  jclass clazz,
+                                  const char* method_name,
+                                  const char* jni_signature) {
+  return GetMethodIDInternal(
+      env, clazz, method_name, jni_signature,
+      METHODTYPE_STATIC, EXCEPTIIONCHECK_NO);
 }
 
 bool HasMethod(JNIEnv* env,
                const JavaRef<jclass>& clazz,
                const char* method_name,
                const char* jni_signature) {
   jmethodID method_id =
       env->GetMethodID(clazz.obj(), method_name, jni_signature);
   if (!method_id) {
     ClearException(env);
@@ skipping 117 matching lines @@
   // RVO should avoid any extra copies of the exception string.
   base::android::BuildInfo::GetInstance()->set_java_exception_info(
       GetJavaExceptionInfo(env, java_throwable));
 
   // Now, feel good about it and die.
   CHECK(false);
 }
 
 }  // namespace android
 }  // namespace base