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A library jar that provides APIs for Applications written for the Google Android Platform.
/*
* Copyright (C) 2014 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package android.hardware.camera2.legacy;
import android.hardware.camera2.impl.CameraDeviceImpl;
import android.hardware.camera2.impl.CameraMetadataNative;
import android.os.Handler;
import android.util.Log;
/**
* Emulates a the state of a single Camera2 device.
*
*
* This class acts as the state machine for a camera device. Valid state transitions are given
* in the table below:
*
*
*
* - {@code UNCONFIGURED -> CONFIGURING}
* - {@code CONFIGURING -> IDLE}
* - {@code IDLE -> CONFIGURING}
* - {@code IDLE -> CAPTURING}
* - {@code IDLE -> IDLE}
* - {@code CAPTURING -> IDLE}
* - {@code ANY -> ERROR}
*
*/
public class CameraDeviceState {
private static final String TAG = "CameraDeviceState";
private static final boolean DEBUG = false;
private static final int STATE_ERROR = 0;
private static final int STATE_UNCONFIGURED = 1;
private static final int STATE_CONFIGURING = 2;
private static final int STATE_IDLE = 3;
private static final int STATE_CAPTURING = 4;
private static final String[] sStateNames = { "ERROR", "UNCONFIGURED", "CONFIGURING", "IDLE",
"CAPTURING"};
private int mCurrentState = STATE_UNCONFIGURED;
private int mCurrentError = NO_CAPTURE_ERROR;
private RequestHolder mCurrentRequest = null;
private Handler mCurrentHandler = null;
private CameraDeviceStateListener mCurrentListener = null;
/**
* Error code used by {@link #setCaptureStart} and {@link #setCaptureResult} to indicate that no
* error has occurred.
*/
public static final int NO_CAPTURE_ERROR = -1;
/**
* CameraDeviceStateListener callbacks to be called after state transitions.
*/
public interface CameraDeviceStateListener {
void onError(int errorCode, Object errorArg, RequestHolder holder);
void onConfiguring();
void onIdle();
void onBusy();
void onCaptureStarted(RequestHolder holder, long timestamp);
void onCaptureResult(CameraMetadataNative result, RequestHolder holder);
void onRepeatingRequestError(long lastFrameNumber);
}
/**
* Transition to the {@code ERROR} state.
*
*
* The device cannot exit the {@code ERROR} state. If the device was not already in the
* {@code ERROR} state, {@link CameraDeviceStateListener#onError(int, RequestHolder)} will be
* called.
*
*
* @param error the error to set. Should be one of the error codes defined in
* {@link CameraDeviceImpl.CameraDeviceCallbacks}.
*/
public synchronized void setError(int error) {
mCurrentError = error;
doStateTransition(STATE_ERROR);
}
/**
* Transition to the {@code CONFIGURING} state, or {@code ERROR} if in an invalid state.
*
*
* If the device was not already in the {@code CONFIGURING} state,
* {@link CameraDeviceStateListener#onConfiguring()} will be called.
*
*
* @return {@code false} if an error has occurred.
*/
public synchronized boolean setConfiguring() {
doStateTransition(STATE_CONFIGURING);
return mCurrentError == NO_CAPTURE_ERROR;
}
/**
* Transition to the {@code IDLE} state, or {@code ERROR} if in an invalid state.
*
*
* If the device was not already in the {@code IDLE} state,
* {@link CameraDeviceStateListener#onIdle()} will be called.
*
*
* @return {@code false} if an error has occurred.
*/
public synchronized boolean setIdle() {
doStateTransition(STATE_IDLE);
return mCurrentError == NO_CAPTURE_ERROR;
}
/**
* Transition to the {@code CAPTURING} state, or {@code ERROR} if in an invalid state.
*
*
* If the device was not already in the {@code CAPTURING} state,
* {@link CameraDeviceStateListener#onCaptureStarted(RequestHolder)} will be called.
*
*
* @param request A {@link RequestHolder} containing the request for the current capture.
* @param timestamp The timestamp of the capture start in nanoseconds.
* @param captureError Report a recoverable error for a single request using a valid
* error code for {@code ICameraDeviceCallbacks}, or
* {@link #NO_CAPTURE_ERROR}
* @return {@code false} if an error has occurred.
*/
public synchronized boolean setCaptureStart(final RequestHolder request, long timestamp,
int captureError) {
mCurrentRequest = request;
doStateTransition(STATE_CAPTURING, timestamp, captureError);
return mCurrentError == NO_CAPTURE_ERROR;
}
/**
* Set the result for a capture.
*
*
* If the device was in the {@code CAPTURING} state,
* {@link CameraDeviceStateListener#onCaptureResult(CameraMetadataNative, RequestHolder)} will
* be called with the given result, otherwise this will result in the device transitioning to
* the {@code ERROR} state,
*
*
* @param request The {@link RequestHolder} request that created this result.
* @param result The {@link CameraMetadataNative} result to set.
* @param captureError Report a recoverable error for a single buffer or result using a valid
* error code for {@code ICameraDeviceCallbacks}, or
* {@link #NO_CAPTURE_ERROR}.
* @param captureErrorArg An argument for some error captureError codes.
* @return {@code false} if an error has occurred.
*/
public synchronized boolean setCaptureResult(final RequestHolder request,
final CameraMetadataNative result,
final int captureError, final Object captureErrorArg) {
if (mCurrentState != STATE_CAPTURING) {
Log.e(TAG, "Cannot receive result while in state: " + mCurrentState);
mCurrentError = CameraDeviceImpl.CameraDeviceCallbacks.ERROR_CAMERA_DEVICE;
doStateTransition(STATE_ERROR);
return mCurrentError == NO_CAPTURE_ERROR;
}
if (mCurrentHandler != null && mCurrentListener != null) {
if (captureError != NO_CAPTURE_ERROR) {
mCurrentHandler.post(new Runnable() {
@Override
public void run() {
mCurrentListener.onError(captureError, captureErrorArg, request);
}
});
} else {
mCurrentHandler.post(new Runnable() {
@Override
public void run() {
mCurrentListener.onCaptureResult(result, request);
}
});
}
}
return mCurrentError == NO_CAPTURE_ERROR;
}
public synchronized boolean setCaptureResult(final RequestHolder request,
final CameraMetadataNative result) {
return setCaptureResult(request, result, NO_CAPTURE_ERROR, /*errorArg*/null);
}
/**
* Set repeating request error.
*
* Repeating request has been stopped due to an error such as abandoned output surfaces.
*
* @param lastFrameNumber Frame number of the last repeating request before it is stopped.
*/
public synchronized void setRepeatingRequestError(final long lastFrameNumber) {
mCurrentHandler.post(new Runnable() {
@Override
public void run() {
mCurrentListener.onRepeatingRequestError(lastFrameNumber);
}
});
}
/**
* Set the listener for state transition callbacks.
*
* @param handler handler on which to call the callbacks.
* @param listener the {@link CameraDeviceStateListener} callbacks to call.
*/
public synchronized void setCameraDeviceCallbacks(Handler handler,
CameraDeviceStateListener listener) {
mCurrentHandler = handler;
mCurrentListener = listener;
}
private void doStateTransition(int newState) {
doStateTransition(newState, /*timestamp*/0, NO_CAPTURE_ERROR);
}
private void doStateTransition(int newState, final long timestamp, final int error) {
if (newState != mCurrentState) {
String stateName = "UNKNOWN";
if (newState >= 0 && newState < sStateNames.length) {
stateName = sStateNames[newState];
}
Log.i(TAG, "Legacy camera service transitioning to state " + stateName);
}
// If we transitioned into a non-IDLE/non-ERROR state then mark the device as busy
if(newState != STATE_ERROR && newState != STATE_IDLE) {
if (mCurrentState != newState && mCurrentHandler != null &&
mCurrentListener != null) {
mCurrentHandler.post(new Runnable() {
@Override
public void run() {
mCurrentListener.onBusy();
}
});
}
}
switch(newState) {
case STATE_ERROR:
if (mCurrentState != STATE_ERROR && mCurrentHandler != null &&
mCurrentListener != null) {
mCurrentHandler.post(new Runnable() {
@Override
public void run() {
mCurrentListener.onError(mCurrentError, /*errorArg*/null, mCurrentRequest);
}
});
}
mCurrentState = STATE_ERROR;
break;
case STATE_CONFIGURING:
if (mCurrentState != STATE_UNCONFIGURED && mCurrentState != STATE_IDLE) {
Log.e(TAG, "Cannot call configure while in state: " + mCurrentState);
mCurrentError = CameraDeviceImpl.CameraDeviceCallbacks.ERROR_CAMERA_DEVICE;
doStateTransition(STATE_ERROR);
break;
}
if (mCurrentState != STATE_CONFIGURING && mCurrentHandler != null &&
mCurrentListener != null) {
mCurrentHandler.post(new Runnable() {
@Override
public void run() {
mCurrentListener.onConfiguring();
}
});
}
mCurrentState = STATE_CONFIGURING;
break;
case STATE_IDLE:
if (mCurrentState == STATE_IDLE) {
break;
}
if (mCurrentState != STATE_CONFIGURING && mCurrentState != STATE_CAPTURING) {
Log.e(TAG, "Cannot call idle while in state: " + mCurrentState);
mCurrentError = CameraDeviceImpl.CameraDeviceCallbacks.ERROR_CAMERA_DEVICE;
doStateTransition(STATE_ERROR);
break;
}
if (mCurrentState != STATE_IDLE && mCurrentHandler != null &&
mCurrentListener != null) {
mCurrentHandler.post(new Runnable() {
@Override
public void run() {
mCurrentListener.onIdle();
}
});
}
mCurrentState = STATE_IDLE;
break;
case STATE_CAPTURING:
if (mCurrentState != STATE_IDLE && mCurrentState != STATE_CAPTURING) {
Log.e(TAG, "Cannot call capture while in state: " + mCurrentState);
mCurrentError = CameraDeviceImpl.CameraDeviceCallbacks.ERROR_CAMERA_DEVICE;
doStateTransition(STATE_ERROR);
break;
}
if (mCurrentHandler != null && mCurrentListener != null) {
if (error != NO_CAPTURE_ERROR) {
mCurrentHandler.post(new Runnable() {
@Override
public void run() {
mCurrentListener.onError(error, /*errorArg*/null, mCurrentRequest);
}
});
} else {
mCurrentHandler.post(new Runnable() {
@Override
public void run() {
mCurrentListener.onCaptureStarted(mCurrentRequest, timestamp);
}
});
}
}
mCurrentState = STATE_CAPTURING;
break;
default:
throw new IllegalStateException("Transition to unknown state: " + newState);
}
}
}