Home | History | Annotate | Download | only in jni 
      1 /* //device/libs/android_runtime/android_util_FileObserver.cpp
      2 **
      3 ** Copyright 2006, The Android Open Source Project
      4 **
      5 ** Licensed under the Apache License, Version 2.0 (the "License");
      6 ** you may not use this file except in compliance with the License.
      7 ** You may obtain a copy of the License at
      8 **
      9 **     http://www.apache.org/licenses/LICENSE-2.0
     10 **
     11 ** Unless required by applicable law or agreed to in writing, software
     12 ** distributed under the License is distributed on an "AS IS" BASIS,
     13 ** WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
     14 ** See the License for the specific language governing permissions and
     15 ** limitations under the License.
     16 */
     17 
     18 #include <nativehelper/JNIHelp.h>
     19 #include "jni.h"
     20 #include "utils/Log.h"
     21 #include "utils/misc.h"
     22 #include "core_jni_helpers.h"
     23 
     24 #include <stdio.h>
     25 #include <stdlib.h>
     26 #include <string.h>
     27 #include <stdint.h>
     28 #include <fcntl.h>
     29 #include <sys/ioctl.h>
     30 #include <errno.h>
     31 
     32 #if defined(__linux__)
     33 #include <sys/inotify.h>
     34 #endif
     35 
     36 namespace android {
     37 
     38 static jmethodID method_onEvent;
     39 
     40 static jint android_os_fileobserver_init(JNIEnv* env, jobject object)
     41 {
     42 #if defined(__linux__)
     43     return (jint)inotify_init();
     44 #else
     45     return -1;
     46 #endif
     47 }
     48 
     49 static void android_os_fileobserver_observe(JNIEnv* env, jobject object, jint fd)
     50 {
     51 #if defined(__linux__)
     52 
     53     char event_buf[512];
     54     struct inotify_event* event;
     55 
     56     while (1)
     57     {
     58         int event_pos = 0;
     59         int num_bytes = read(fd, event_buf, sizeof(event_buf));
     60 
     61         if (num_bytes < (int)sizeof(*event))
     62         {
     63             if (errno == EINTR)
     64                 continue;
     65 
     66             ALOGE("***** ERROR! android_os_fileobserver_observe() got a short event!");
     67             return;
     68         }
     69 
     70         while (num_bytes >= (int)sizeof(*event))
     71         {
     72             int event_size;
     73             event = (struct inotify_event *)(event_buf + event_pos);
     74 
     75             jstring path = NULL;
     76 
     77             if (event->len > 0)
     78             {
     79                 path = env->NewStringUTF(event->name);
     80             }
     81 
     82             env->CallVoidMethod(object, method_onEvent, event->wd, event->mask, path);
     83             if (env->ExceptionCheck()) {
     84                 env->ExceptionDescribe();
     85                 env->ExceptionClear();
     86             }
     87             if (path != NULL)
     88             {
     89                 env->DeleteLocalRef(path);
     90             }
     91 
     92             event_size = sizeof(*event) + event->len;
     93             num_bytes -= event_size;
     94             event_pos += event_size;
     95         }
     96     }
     97 
     98 #endif
     99 }
    100 
    101 static jint android_os_fileobserver_startWatching(JNIEnv* env, jobject object, jint fd, jstring pathString, jint mask)
    102 {
    103     int res = -1;
    104 
    105 #if defined(__linux__)
    106 
    107     if (fd >= 0)
    108     {
    109         const char* path = env->GetStringUTFChars(pathString, NULL);
    110 
    111         res = inotify_add_watch(fd, path, mask);
    112 
    113         env->ReleaseStringUTFChars(pathString, path);
    114     }
    115 
    116 #endif
    117 
    118     return res;
    119 }
    120 
    121 static void android_os_fileobserver_stopWatching(JNIEnv* env, jobject object, jint fd, jint wfd)
    122 {
    123 #if defined(__linux__)
    124 
    125     inotify_rm_watch((int)fd, (uint32_t)wfd);
    126 
    127 #endif
    128 }
    129 
    130 static const JNINativeMethod sMethods[] = {
    131      /* name, signature, funcPtr */
    132     { "init", "()I", (void*)android_os_fileobserver_init },
    133     { "observe", "(I)V", (void*)android_os_fileobserver_observe },
    134     { "startWatching", "(ILjava/lang/String;I)I", (void*)android_os_fileobserver_startWatching },
    135     { "stopWatching", "(II)V", (void*)android_os_fileobserver_stopWatching }
    136 
    137 };
    138 
    139 int register_android_os_FileObserver(JNIEnv* env)
    140 {
    141     jclass clazz = FindClassOrDie(env, "android/os/FileObserver$ObserverThread");
    142 
    143     method_onEvent = GetMethodIDOrDie(env, clazz, "onEvent", "(IILjava/lang/String;)V");
    144 
    145     return RegisterMethodsOrDie(env, "android/os/FileObserver$ObserverThread", sMethods,
    146                                 NELEM(sMethods));
    147 }
    148 
    149 } /* namespace android */
    150