Camera: Add support for hidden physical camera ID

Add the support where characteristics of a hidden physical camera ID can be
queried by getCameraCharacteristics, but openCamera() cannot open that
camera.

Test: make offline-sdk-docs
Test: Camera CTS
Bug: 79523700
Change-Id: I0876f924da13e0e70ed0bf09ad937f08b076d492

3 files changed, 52 insertions, 7 deletions

diff --git a/core/java/android/hardware/camera2/CameraCharacteristics.java b/core/java/android/hardware/camera2/CameraCharacteristics.java
index 35584ae21869..07fe73066fd0 100644
--- a/core/java/android/hardware/camera2/CameraCharacteristics.java
+++ b/core/java/android/hardware/camera2/CameraCharacteristics.java
@@ -474,6 +474,13 @@ public final class CameraCharacteristics extends CameraMetadata<CameraCharacteri
      * REQUEST_AVAILABLE_CAPABILITIES_LOGICAL_MULTI_CAMERA capability. If the camera device
      * doesn't have the capability, the return value will be an empty set. </p>
      *
+     * <p>Prior to API level 29, all returned IDs are guaranteed to be returned by {@link
+     * CameraManager#getCameraIdList}, and can be opened directly by
+     * {@link CameraManager#openCamera}. Starting from API level 29, for each of the returned ID,
+     * if it's also returned by {@link CameraManager#getCameraIdList}, it can be used as a
+     * standalone camera by {@link CameraManager#openCamera}. Otherwise, the camera ID can only be
+     * used as part of the current logical camera.</p>
+     *
      * <p>The set returned is not modifiable, so any attempts to modify it will throw
      * a {@code UnsupportedOperationException}.</p>
      *
diff --git a/core/java/android/hardware/camera2/CameraManager.java b/core/java/android/hardware/camera2/CameraManager.java
index 7ebe0f9a8d8d..44d7364ce43c 100644
--- a/core/java/android/hardware/camera2/CameraManager.java
+++ b/core/java/android/hardware/camera2/CameraManager.java
@@ -34,7 +34,6 @@ import android.os.Binder;
 import android.os.DeadObjectException;
 import android.os.Handler;
 import android.os.IBinder;
-import android.os.Looper;
 import android.os.RemoteException;
 import android.os.ServiceManager;
 import android.os.ServiceSpecificException;
@@ -45,7 +44,6 @@ import android.util.Log;
 import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.Comparator;
-
 import java.util.concurrent.Executor;
 import java.util.concurrent.Executors;
 import java.util.concurrent.RejectedExecutionException;
@@ -97,6 +95,9 @@ public final class CameraManager {
      * identifiers, while removable cameras have a unique identifier for each
      * individual device, even if they are the same model.</p>
      *
+     * <p>This list doesn't contain physical cameras that can only used as part of a logical
+     * multi-camera device.</p>
+     *
      * @return The list of currently connected camera devices.
      */
     @NonNull
@@ -234,7 +235,13 @@ public final class CameraManager {
      * <p>Query the capabilities of a camera device. These capabilities are
      * immutable for a given camera.</p>
      *
-     * @param cameraId The id of the camera device to query
+     * <p>From API level 29, this function can also be used to query the capabilities of physical
+     * cameras that can only be used as part of logical multi-camera. These cameras cannot not be
+     * opened directly via {@link #openCamera}</p>
+     *
+     * @param cameraId The id of the camera device to query. This could be either a standalone
+     * camera ID which can be directly opened by {@link #openCamera}, or a physical camera ID that
+     * can only used as part of a logical multi-camera.
      * @return The properties of the given camera
      *
      * @throws IllegalArgumentException if the cameraId does not match any
@@ -262,7 +269,9 @@ public final class CameraManager {
                         "Camera service is currently unavailable");
             }
             try {
-                if (!supportsCamera2ApiLocked(cameraId)) {
+                // First check isHiddenPhysicalCamera to avoid supportsCamera2ApiLocked throwing
+                // exception in case cameraId is a hidden physical camera.
+                if (!isHiddenPhysicalCamera(cameraId) && !supportsCamera2ApiLocked(cameraId)) {
                     // Legacy backwards compatibility path; build static info from the camera
                     // parameters
                     int id = Integer.parseInt(cameraId);
@@ -454,7 +463,7 @@ public final class CameraManager {
      *
      * @throws IllegalArgumentException if cameraId or the callback was null,
      * or the cameraId does not match any currently or previously available
-     * camera device.
+     * camera device returned by {@link #getCameraIdList}.
      *
      * @throws SecurityException if the application does not have permission to
      * access the camera
@@ -778,6 +787,29 @@ public final class CameraManager {
     }
 
     /**
+     * Queries the camera service if a cameraId is a hidden physical camera that belongs to a
+     * logical camera device.
+     *
+     * A hidden physical camera is a camera that cannot be opened by the application. But it
+     * can be used as part of a logical camera.
+     *
+     * @param cameraId a non-{@code null} camera identifier
+     * @return {@code true} if cameraId is a hidden physical camera device
+     */
+    private boolean isHiddenPhysicalCamera(String cameraId) {
+        try {
+            ICameraService cameraService = CameraManagerGlobal.get().getCameraService();
+            // If no camera service, no support
+            if (cameraService == null) return false;
+
+            return cameraService.isHiddenPhysicalCamera(cameraId);
+        } catch (RemoteException e) {
+            // Camera service is now down, no support for any API level
+        }
+        return false;
+    }
+
+    /**
      * A per-process global camera manager instance, to retain a connection to the camera service,
      * and to distribute camera availability notices to API-registered callbacks
      */
diff --git a/core/java/android/hardware/camera2/CameraMetadata.java b/core/java/android/hardware/camera2/CameraMetadata.java
index caa99d5cb2a8..b6db6f22a498 100644
--- a/core/java/android/hardware/camera2/CameraMetadata.java
+++ b/core/java/android/hardware/camera2/CameraMetadata.java
@@ -811,8 +811,14 @@ public abstract class CameraMetadata<TKey> {
     public static final int REQUEST_AVAILABLE_CAPABILITIES_MOTION_TRACKING = 10;
 
     /**
-     * <p>The camera device is a logical camera backed by two or more physical cameras that are
-     * also exposed to the application.</p>
+     * <p>The camera device is a logical camera backed by two or more physical cameras. In
+     * API level 28, the physical cameras must also be exposed to the application via
+     * {@link android.hardware.camera2.CameraManager#getCameraIdList }. Starting from API
+     * level 29, some or all physical cameras may not be independently exposed to the
+     * application, in which case the physical camera IDs will not be available in
+     * {@link android.hardware.camera2.CameraManager#getCameraIdList }. But the application
+     * can still query the physical cameras' characteristics by calling
+     * {@link android.hardware.camera2.CameraManager#getCameraCharacteristics }.</p>
      * <p>Camera application shouldn't assume that there are at most 1 rear camera and 1 front
      * camera in the system. For an application that switches between front and back cameras,
      * the recommendation is to switch between the first rear camera and the first front