1 /*
2  * Copyright (C) 2013, The Android Open Source Project
3  *
4  * Licensed under the Apache License, Version 2.0 (the "License");
5  * you may not use this file except in compliance with the License.
6  * You may obtain a copy of the License at
7  *
8  *     http://www.apache.org/licenses/LICENSE-2.0
9  *
10  * Unless required by applicable law or agreed to in writing, software
11  * distributed under the License is distributed on an "AS IS" BASIS,
12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13  * See the License for the specific language governing permissions and
14  * limitations under the License.
15  */
16 
17 #include "log_utils.h"
18 
19 #include <cstdio>
20 #include <stdarg.h>
21 
22 #include "defines.h"
23 
24 namespace latinime {
logToJava(JNIEnv * const env,const char * const format,...)25     /* static */ void LogUtils::logToJava(JNIEnv *const env, const char *const format, ...) {
26         static const char *TAG = "LatinIME:LogUtils";
27         const jclass androidUtilLogClass = env->FindClass("android/util/Log");
28         if (!androidUtilLogClass) {
29             // If we can't find the class, we are probably in off-device testing, and
30             // it's expected. Regardless, logging is not essential to functionality, so
31             // we should just return. However, FindClass has thrown an exception behind
32             // our back and there is no way to prevent it from doing that, so we clear
33             // the exception before we return.
34             env->ExceptionClear();
35             return;
36         }
37         const jmethodID logDotIMethodId = env->GetStaticMethodID(androidUtilLogClass, "i",
38                 "(Ljava/lang/String;Ljava/lang/String;)I");
39         if (!logDotIMethodId) {
40             env->ExceptionClear();
41             if (androidUtilLogClass) env->DeleteLocalRef(androidUtilLogClass);
42             return;
43         }
44         const jstring javaTag = env->NewStringUTF(TAG);
45 
46         static const int DEFAULT_LINE_SIZE = 128;
47         char fixedSizeCString[DEFAULT_LINE_SIZE];
48         va_list argList;
49         va_start(argList, format);
50         // Get the necessary size. Add 1 for the 0 terminator.
51         const int size = vsnprintf(fixedSizeCString, DEFAULT_LINE_SIZE, format, argList) + 1;
52         va_end(argList);
53 
54         jstring javaString;
55         if (size <= DEFAULT_LINE_SIZE) {
56             // The buffer was large enough.
57             javaString = env->NewStringUTF(fixedSizeCString);
58         } else {
59             // The buffer was not large enough.
60             va_start(argList, format);
61             char variableSizeCString[size];
62             vsnprintf(variableSizeCString, size, format, argList);
63             va_end(argList);
64             javaString = env->NewStringUTF(variableSizeCString);
65         }
66 
67         env->CallStaticIntMethod(androidUtilLogClass, logDotIMethodId, javaTag, javaString);
68         if (javaString) env->DeleteLocalRef(javaString);
69         if (javaTag) env->DeleteLocalRef(javaTag);
70         if (androidUtilLogClass) env->DeleteLocalRef(androidUtilLogClass);
71     }
72 }
73