static jint nativeWaitWakeup(JNIEnv *env, jobject clazz, jintArray outIrqs,
        jobjectArray outReasons)
{
    bool first_time = false;

    if (outIrqs == NULL || outReasons == NULL) {
        jniThrowException(env, "java/lang/NullPointerException", "null argument");
        return -1;
    }

    // Register our wakeup callback if not yet done.
    if (!wakeup_init) {
        wakeup_init = true;
        ALOGV("Creating semaphore...");
        int ret = sem_init(&wakeup_sem, 0, 0);
        if (ret < 0) {
            char buf[80];
            strerror_r(errno, buf, sizeof(buf));
            ALOGE("Error creating semaphore: %s\n", buf);
            jniThrowException(env, "java/lang/IllegalStateException", buf);
            return -1;
        }
        ALOGV("Registering callback...");
        set_wakeup_callback(&wakeup_callback);
        // First time through, we will just drain the current wakeup reasons.
        first_time = true;
    } else {
        // On following calls, we need to wait for wakeup.
        ALOGV("Waiting for wakeup...");
        int ret = sem_wait(&wakeup_sem);
        if (ret < 0) {
            char buf[80];
            strerror_r(errno, buf, sizeof(buf));
            ALOGE("Error waiting on semaphore: %s\n", buf);
            // Return 0 here to let it continue looping but not return results.
            return 0;
        }
    }

    FILE *fp = fopen(LAST_RESUME_REASON, "r");
    if (fp == NULL) {
        ALOGE("Failed to open %s", LAST_RESUME_REASON);
        return -1;
    }

    int numOut = env->GetArrayLength(outIrqs);
    ScopedIntArrayRW irqs(env, outIrqs);

    ALOGV("Reading up to %d wakeup reasons", numOut);

    char mergedreason[MAX_REASON_SIZE];
    char* mergedreasonpos = mergedreason;
    int remainreasonlen = MAX_REASON_SIZE;
    int firstirq = 0;
    char reasonline[128];
    int i = 0;
    while (fgets(reasonline, sizeof(reasonline), fp) != NULL && i < numOut) {
        char* pos = reasonline;
        char* endPos;
        // First field is the index.
        int irq = (int)strtol(pos, &endPos, 10);
        if (pos == endPos) {
            // Ooops.
            ALOGE("Bad reason line: %s", reasonline);
            continue;
        }
        pos = endPos;
        // Skip whitespace; rest of the buffer is the reason string.
        while (*pos == ' ') {
            pos++;
        }
        // Chop newline at end.
        char* endpos = pos;
        while (*endpos != 0) {
            if (*endpos == '\n') {
                *endpos = 0;
                break;
            }
            endpos++;
        }
        // For now we are not separating out the first irq.
        // This is because in practice there are always multiple
        // lines of wakeup reasons, so it is better to just treat
        // them all together as a single string.
        if (false && i == 0) {
            firstirq = irq;
        } else {
            int len = snprintf(mergedreasonpos, remainreasonlen,
                    i == 0 ? "%d" : ":%d", irq);
            if (len >= 0 && len < remainreasonlen) {
                mergedreasonpos += len;
                remainreasonlen -= len;
            }
        }
        int len = snprintf(mergedreasonpos, remainreasonlen, ":%s", pos);
        if (len >= 0 && len < remainreasonlen) {
            mergedreasonpos += len;
            remainreasonlen -= len;
        }
        // For now it is better to combine all of these in to one entry in the
        // battery history.  In the future, it might be nice to figure out a way
        // to efficiently store multiple lines as a single entry in the history.
        //irqs[i] = irq;
        //ScopedLocalRef<jstring> reasonString(env, env->NewStringUTF(pos));
        //env->SetObjectArrayElement(outReasons, i, reasonString.get());
        //ALOGV("Wakeup reason #%d: irw %d reason %s", i, irq, pos);
        i++;
    }

    ALOGV("Got %d reasons", i);
    if (first_time) {
        i = 0;
    }
    if (i > 0) {
        irqs[0] = firstirq;
        *mergedreasonpos = 0;
        ScopedLocalRef<jstring> reasonString(env, env->NewStringUTF(mergedreason));
        env->SetObjectArrayElement(outReasons, 0, reasonString.get());
        i = 1;
    }

    if (fclose(fp) != 0) {
        ALOGE("Failed to close %s", LAST_RESUME_REASON);
        return -1;
    }

    return first_time ? 0 : i;
}
static jint nativeWaitWakeup(JNIEnv *env, jobject clazz, jobject outBuf)
{
    if (outBuf == NULL) {
        jniThrowException(env, "java/lang/NullPointerException", "null argument");
        return -1;
    }

    // Register our wakeup callback if not yet done.
    if (!wakeup_init) {
        wakeup_init = true;
        ALOGV("Creating semaphore...");
        int ret = sem_init(&wakeup_sem, 0, 0);
        if (ret < 0) {
            char buf[80];
            strerror_r(errno, buf, sizeof(buf));
            ALOGE("Error creating semaphore: %s\n", buf);
            jniThrowException(env, "java/lang/IllegalStateException", buf);
            return -1;
        }
        ALOGV("Registering callback...");
        set_wakeup_callback(&wakeup_callback);
    }

    // Wait for wakeup.
    ALOGV("Waiting for wakeup...");
    int ret = sem_wait(&wakeup_sem);
    if (ret < 0) {
        char buf[80];
        strerror_r(errno, buf, sizeof(buf));
        ALOGE("Error waiting on semaphore: %s\n", buf);
        // Return 0 here to let it continue looping but not return results.
        return 0;
    }

    FILE *fp = fopen(LAST_RESUME_REASON, "r");
    if (fp == NULL) {
        ALOGE("Failed to open %s", LAST_RESUME_REASON);
        return -1;
    }

    char* mergedreason = (char*)env->GetDirectBufferAddress(outBuf);
    int remainreasonlen = (int)env->GetDirectBufferCapacity(outBuf);

    ALOGV("Reading wakeup reasons");
    char* mergedreasonpos = mergedreason;
    char reasonline[128];
    int i = 0;
    while (fgets(reasonline, sizeof(reasonline), fp) != NULL) {
        char* pos = reasonline;
        char* endPos;
        int len;
        // First field is the index or 'Abort'.
        int irq = (int)strtol(pos, &endPos, 10);
        if (pos != endPos) {
            // Write the irq number to the merged reason string.
            len = snprintf(mergedreasonpos, remainreasonlen, i == 0 ? "%d" : ":%d", irq);
        } else {
            // The first field is not an irq, it may be the word Abort.
            const size_t abortPrefixLen = strlen("Abort:");
            if (strncmp(pos, "Abort:", abortPrefixLen) != 0) {
                // Ooops.
                ALOGE("Bad reason line: %s", reasonline);
                continue;
            }

            // Write 'Abort' to the merged reason string.
            len = snprintf(mergedreasonpos, remainreasonlen, i == 0 ? "Abort" : ":Abort");
            endPos = pos + abortPrefixLen;
        }
        pos = endPos;

        if (len >= 0 && len < remainreasonlen) {
            mergedreasonpos += len;
            remainreasonlen -= len;
        }

        // Skip whitespace; rest of the buffer is the reason string.
        while (*pos == ' ') {
            pos++;
        }

        // Chop newline at end.
        char* endpos = pos;
        while (*endpos != 0) {
            if (*endpos == '\n') {
                *endpos = 0;
                break;
            }
            endpos++;
        }

        len = snprintf(mergedreasonpos, remainreasonlen, ":%s", pos);
        if (len >= 0 && len < remainreasonlen) {
            mergedreasonpos += len;
            remainreasonlen -= len;
        }
        i++;
    }

    ALOGV("Got %d reasons", i);
    if (i > 0) {
        *mergedreasonpos = 0;
    }

    if (fclose(fp) != 0) {
        ALOGE("Failed to close %s", LAST_RESUME_REASON);
        return -1;
    }
    return mergedreasonpos - mergedreason;
}