Camera2: Add support for partial result metadata quirk

- Add new CaptureListener.onCapturePartial() callback for receiving
  partial result metadata sooner than the full result metadata will be sent
  in onCaptureComplete().
- Add hidden keys for the partial result quirk
- Dispatch results to onCapturePartial based on the partial result quirk

All additions are hidden for now.

Bug: 11115603
Change-Id: Ie9a3be640f147257ae22e5b5edf0974bddc1cb85

4 files changed, 105 insertions, 5 deletions

diff --git a/core/java/android/hardware/camera2/CameraCharacteristics.java b/core/java/android/hardware/camera2/CameraCharacteristics.java
index 4fe2c4d..a38beec 100644
--- a/core/java/android/hardware/camera2/CameraCharacteristics.java
+++ b/core/java/android/hardware/camera2/CameraCharacteristics.java
@@ -334,6 +334,27 @@ public final class CameraCharacteristics extends CameraMetadata {
 
     /**
      * <p>
+     * If set to 1, the HAL will always split result
+     * metadata for a single capture into multiple buffers,
+     * returned using multiple process_capture_result calls.
+     * </p>
+     * <p>
+     * Does not need to be listed in static
+     * metadata. Support for partial results will be reworked in
+     * future versions of camera service. This quirk will stop
+     * working at that point; DO NOT USE without careful
+     * consideration of future support.
+     * </p>
+     *
+     * <b>Optional</b> - This value may be null on some devices.
+     *
+     * @hide
+     */
+    public static final Key<Byte> QUIRKS_USE_PARTIAL_RESULT =
+            new Key<Byte>("android.quirks.usePartialResult", byte.class);
+
+    /**
+     * <p>
      * How many output streams can be allocated at
      * the same time for each type of stream
      * </p>
diff --git a/core/java/android/hardware/camera2/CameraDevice.java b/core/java/android/hardware/camera2/CameraDevice.java
index 7095e4d..9e8d7d1 100644
--- a/core/java/android/hardware/camera2/CameraDevice.java
+++ b/core/java/android/hardware/camera2/CameraDevice.java
@@ -631,6 +631,36 @@ public interface CameraDevice extends AutoCloseable {
         }
 
         /**
+         * This method is called when some results from an image capture are
+         * available.
+         *
+         * <p>The result provided here will contain some subset of the fields of
+         * a full result. Multiple onCapturePartial calls may happen per
+         * capture; a given result field will only be present in one partial
+         * capture at most. The final onCaptureCompleted call will always
+         * contain all the fields, whether onCapturePartial was called or
+         * not.</p>
+         *
+         * <p>The default implementation of this method does nothing.</p>
+         *
+         * @param camera The CameraDevice sending the callback.
+         * @param request The request that was given to the CameraDevice
+         * @param result The partial output metadata from the capture, which
+         * includes a subset of the CaptureResult fields.
+         *
+         * @see #capture
+         * @see #captureBurst
+         * @see #setRepeatingRequest
+         * @see #setRepeatingBurst
+         *
+         * @hide
+         */
+        public void onCapturePartial(CameraDevice camera,
+                CaptureRequest request, CaptureResult result) {
+            // default empty implementation
+        }
+
+        /**
          * This method is called when an image capture has completed and the
          * result metadata is available.
          *
diff --git a/core/java/android/hardware/camera2/CaptureResult.java b/core/java/android/hardware/camera2/CaptureResult.java
index dbd0457..535b963 100644
--- a/core/java/android/hardware/camera2/CaptureResult.java
+++ b/core/java/android/hardware/camera2/CaptureResult.java
@@ -591,6 +591,32 @@ public final class CaptureResult extends CameraMetadata {
 
     /**
      * <p>
+     * Whether a result given to the framework is the
+     * final one for the capture, or only a partial that contains a
+     * subset of the full set of dynamic metadata
+     * values.
+     * </p>
+     * <p>
+     * The entries in the result metadata buffers for a
+     * single capture may not overlap, except for this entry. The
+     * FINAL buffers must retain FIFO ordering relative to the
+     * requests that generate them, so the FINAL buffer for frame 3 must
+     * always be sent to the framework after the FINAL buffer for frame 2, and
+     * before the FINAL buffer for frame 4. PARTIAL buffers may be returned
+     * in any order relative to other frames, but all PARTIAL buffers for a given
+     * capture must arrive before the FINAL buffer for that capture. This entry may
+     * only be used by the HAL if quirks.usePartialResult is set to 1.
+     * </p>
+     *
+     * <b>Optional</b> - This value may be null on some devices.
+     *
+     * @hide
+     */
+    public static final Key<Boolean> QUIRKS_PARTIAL_RESULT =
+            new Key<Boolean>("android.quirks.partialResult", boolean.class);
+
+    /**
+     * <p>
      * A frame counter set by the framework. This value monotonically
      * increases with every new result (that is, each new result has a unique
      * frameCount value).
diff --git a/core/java/android/hardware/camera2/impl/CameraDevice.java b/core/java/android/hardware/camera2/impl/CameraDevice.java
index 814aa96..40586f0 100644
--- a/core/java/android/hardware/camera2/impl/CameraDevice.java
+++ b/core/java/android/hardware/camera2/impl/CameraDevice.java
@@ -577,6 +577,9 @@ public class CameraDevice implements android.hardware.camera2.CameraDevice {
             }
             final CaptureListenerHolder holder;
 
+            Boolean quirkPartial = result.get(CaptureResult.QUIRKS_PARTIAL_RESULT);
+            boolean quirkIsPartialResult = (quirkPartial != null && quirkPartial);
+
             synchronized (mLock) {
                 // TODO: move this whole map into this class to make it more testable,
                 //        exposing the methods necessary like subscribeToRequest, unsubscribe..
@@ -585,7 +588,7 @@ public class CameraDevice implements android.hardware.camera2.CameraDevice {
                 holder = CameraDevice.this.mCaptureListenerMap.get(requestId);
 
                 // Clean up listener once we no longer expect to see it.
-                if (holder != null && !holder.isRepeating()) {
+                if (holder != null && !holder.isRepeating() && !quirkIsPartialResult) {
                     CameraDevice.this.mCaptureListenerMap.remove(requestId);
                 }
 
@@ -595,7 +598,7 @@ public class CameraDevice implements android.hardware.camera2.CameraDevice {
                 // If we received a result for a repeating request and have
                 // prior repeating requests queued for deletion, remove those
                 // requests from mCaptureListenerMap.
-                if (holder != null && holder.isRepeating()
+                if (holder != null && holder.isRepeating() && !quirkIsPartialResult
                         && mRepeatingRequestIdDeletedList.size() > 0) {
                     Iterator<Integer> iter = mRepeatingRequestIdDeletedList.iterator();
                     while (iter.hasNext()) {
@@ -619,8 +622,25 @@ public class CameraDevice implements android.hardware.camera2.CameraDevice {
             final CaptureRequest request = holder.getRequest();
             final CaptureResult resultAsCapture = new CaptureResult(result, request, requestId);
 
-            holder.getHandler().post(
-                new Runnable() {
+            Runnable resultDispatch = null;
+
+            // Either send a partial result or the final capture completed result
+            if (quirkIsPartialResult) {
+                // Partial result
+                resultDispatch = new Runnable() {
+                    @Override
+                    public void run() {
+                        if (!CameraDevice.this.isClosed()){
+                            holder.getListener().onCapturePartial(
+                                CameraDevice.this,
+                                request,
+                                resultAsCapture);
+                        }
+                    }
+                };
+            } else {
+                // Final capture result
+                resultDispatch = new Runnable() {
                     @Override
                     public void run() {
                         if (!CameraDevice.this.isClosed()){
@@ -630,7 +650,10 @@ public class CameraDevice implements android.hardware.camera2.CameraDevice {
                                 resultAsCapture);
                         }
                     }
-                });
+                };
+            }
+
+            holder.getHandler().post(resultDispatch);
         }
 
     }