Add metadata support to MTP docs provider.

Remove convenience method from DocumentsProvider, clients to use MetadataReader directly.
Concentrate mimetype checking in MetadataReader.isSupportedType.
Update FileSystemProvider to use MetadataReader directly.

Test: Updated mtp tests. Other functioanlity manually verified.
Change-Id: Ie1e3d3092b53107f6c980c18b1451290dd2a9653

7 files changed, 82 insertions, 58 deletions

diff --git a/core/java/android/provider/DocumentsProvider.java b/core/java/android/provider/DocumentsProvider.java
index 2298134d469b..81b1921dd809 100644
--- a/core/java/android/provider/DocumentsProvider.java
+++ b/core/java/android/provider/DocumentsProvider.java
@@ -66,8 +66,6 @@ import android.util.Log;
 import libcore.io.IoUtils;
 
 import java.io.FileNotFoundException;
-import java.io.IOException;
-import java.io.InputStream;
 import java.util.LinkedList;
 import java.util.Objects;
 
@@ -635,30 +633,6 @@ public abstract class DocumentsProvider extends ContentProvider {
     }
 
     /**
-     * Returns metadata for arbitrary file given its stream and mimetype.
-     *
-     * <p><b>Note: Providers should only call this with streams for locally cached resources.
-     * Use of network backed streams is inadvisable for performance reasons.
-     *
-     * @param stream The input stream. Should be backed by locally cached content.
-     *       Client retains ownership of the stream.
-     * @param mimeType The mime type of the file.
-     * @param tags The list of tags to load, if known. Pass null to get a default set.
-     * @return Bundle containing any metadata found.
-     * @throws IOException in the event of an error reading metadata.
-     *
-     * @hide
-     */
-    protected Bundle getDocumentMetadataFromStream(InputStream stream, String mimeType)
-            throws IOException {
-        Bundle metadata = new Bundle();
-        // TODO: Remove the last null arg from MetadataReader. It was the "tags" value,
-        // the has been removed from the getDocumentMetadata method.
-        MetadataReader.getMetadata(metadata, stream, mimeType, null);
-        return metadata;
-    }
-
-    /**
      * Return concrete MIME type of the requested document. Must match the value
      * of {@link Document#COLUMN_MIME_TYPE} for this document. The default
      * implementation queries {@link #queryDocument(String, String[])}, so
diff --git a/core/java/android/provider/MetadataReader.java b/core/java/android/provider/MetadataReader.java
index 5aa5f72ab788..2d23c4eee130 100644
--- a/core/java/android/provider/MetadataReader.java
+++ b/core/java/android/provider/MetadataReader.java
@@ -36,29 +36,31 @@ import java.util.Map;
  */
 public final class MetadataReader {
 
-    private MetadataReader() {
-    }
+    private MetadataReader() {}
 
     private static final String[] DEFAULT_EXIF_TAGS = {
-            ExifInterface.TAG_IMAGE_WIDTH,
-            ExifInterface.TAG_IMAGE_LENGTH,
+            ExifInterface.TAG_APERTURE,
+            ExifInterface.TAG_COPYRIGHT,
             ExifInterface.TAG_DATETIME,
+            ExifInterface.TAG_EXPOSURE_TIME,
+            ExifInterface.TAG_F_NUMBER,
             ExifInterface.TAG_GPS_LATITUDE,
             ExifInterface.TAG_GPS_LATITUDE_REF,
             ExifInterface.TAG_GPS_LONGITUDE,
             ExifInterface.TAG_GPS_LONGITUDE_REF,
+            ExifInterface.TAG_IMAGE_WIDTH,
+            ExifInterface.TAG_IMAGE_LENGTH,
             ExifInterface.TAG_MAKE,
             ExifInterface.TAG_MODEL,
-            ExifInterface.TAG_APERTURE,
-            ExifInterface.TAG_SHUTTER_SPEED_VALUE
+            ExifInterface.TAG_ORIENTATION,
+            ExifInterface.TAG_SHUTTER_SPEED_VALUE,
     };
 
-    private static final Map<String, Integer> TYPE_MAPPING = new HashMap<>();
-    private static final String[] ALL_KNOWN_EXIF_KEYS;
     private static final int TYPE_INT = 0;
     private static final int TYPE_DOUBLE = 1;
     private static final int TYPE_STRING = 2;
 
+    private static final Map<String, Integer> TYPE_MAPPING = new HashMap<>();
     static {
         // TODO: Move this over to ExifInterface.java
         // Since each ExifInterface item has a type, and there's currently no way to get the type
@@ -198,11 +200,19 @@ public final class MetadataReader {
         TYPE_MAPPING.put(ExifInterface.TAG_RW2_SENSOR_RIGHT_BORDER, TYPE_INT);
         TYPE_MAPPING.put(ExifInterface.TAG_RW2_SENSOR_TOP_BORDER, TYPE_INT);
         TYPE_MAPPING.put(ExifInterface.TAG_RW2_ISO, TYPE_INT);
-        ALL_KNOWN_EXIF_KEYS = TYPE_MAPPING.keySet().toArray(new String[TYPE_MAPPING.size()]);
     }
     private static final String JPG_MIME_TYPE = "image/jpg";
     private static final String JPEG_MIME_TYPE = "image/jpeg";
 
+
+    /**
+     * Returns true if caller can generally expect to get metadata results
+     * for the supplied mimetype.
+     */
+    public static boolean isSupportedMimeType(String mimeType) {
+        return JPG_MIME_TYPE.equals(mimeType) || JPEG_MIME_TYPE.equals(mimeType);
+    }
+
     /**
      * Generic metadata retrieval method that can retrieve any available metadata from a given doc
      * Currently only functions for exifdata
@@ -228,10 +238,9 @@ public final class MetadataReader {
      */
     public static void getMetadata(Bundle metadata, InputStream stream, String mimeType,
             @Nullable String[] tags) throws IOException {
-        List<String> metadataTypes = new ArrayList();
-        if (mimeType.equals(JPG_MIME_TYPE) || mimeType.equals(JPEG_MIME_TYPE)) {
-            ExifInterface exifInterface = new ExifInterface(stream);
-            Bundle exifData = getExifData(exifInterface, tags);
+        List<String> metadataTypes = new ArrayList<>();
+        if (isSupportedMimeType(mimeType)) {
+            Bundle exifData = getExifData(stream, tags);
             if (exifData.size() > 0) {
                 metadata.putBundle(DocumentsContract.METADATA_EXIF, exifData);
                 metadataTypes.add(DocumentsContract.METADATA_EXIF);
@@ -246,8 +255,7 @@ public final class MetadataReader {
     /**
      * Helper method that is called if getMetadata is called for an image mimeType.
      *
-     * @param exif the bundle to which we add exif data.
-     * @param exifInterface an ExifInterface for an image
+     * @param stream the input stream from which to extra data.
      * @param tags a list of ExifInterface tags that are used to retrieve data.
      *             if null, returns a default set of data from the following keys:
      *             ExifInterface.TAG_IMAGE_WIDTH,
@@ -262,11 +270,13 @@ public final class MetadataReader {
      *             ExifInterface.TAG_APERTURE,
      *             ExifInterface.TAG_SHUTTER_SPEED_VALUE
      */
-    private static Bundle getExifData(ExifInterface exifInterface, @Nullable String[] tags)
+    private static Bundle getExifData(InputStream stream, @Nullable String[] tags)
             throws IOException {
         if (tags == null) {
             tags = DEFAULT_EXIF_TAGS;
         }
+
+        ExifInterface exifInterface = new ExifInterface(stream);
         Bundle exif = new Bundle();
         for (String tag : tags) {
             if (TYPE_MAPPING.get(tag).equals(TYPE_INT)) {
diff --git a/core/java/com/android/internal/content/FileSystemProvider.java b/core/java/com/android/internal/content/FileSystemProvider.java
index 8c805accfbc5..e3a9b7e41d5b 100644
--- a/core/java/com/android/internal/content/FileSystemProvider.java
+++ b/core/java/com/android/internal/content/FileSystemProvider.java
@@ -28,7 +28,6 @@ import android.database.MatrixCursor.RowBuilder;
 import android.graphics.Point;
 import android.net.Uri;
 import android.os.Binder;
-import android.os.Build;
 import android.os.Bundle;
 import android.os.CancellationSignal;
 import android.os.FileObserver;
@@ -39,6 +38,7 @@ import android.provider.DocumentsContract;
 import android.provider.DocumentsContract.Document;
 import android.provider.DocumentsProvider;
 import android.provider.MediaStore;
+import android.provider.MetadataReader;
 import android.text.TextUtils;
 import android.util.ArrayMap;
 import android.util.Log;
@@ -52,6 +52,7 @@ import java.io.File;
 import java.io.FileInputStream;
 import java.io.FileNotFoundException;
 import java.io.IOException;
+import java.io.InputStream;
 import java.util.LinkedList;
 import java.util.List;
 import java.util.Set;
@@ -120,26 +121,31 @@ public abstract class FileSystemProvider extends DocumentsProvider {
 
         if (!file.isFile()) {
             Log.w(TAG, "Can't stream non-regular file. Returning empty metadata.");
-            return Bundle.EMPTY;
+            return null;
         }
 
         if (!file.canRead()) {
             Log.w(TAG, "Can't stream non-readable file. Returning empty metadata.");
-            return Bundle.EMPTY;
+            return null;
         }
 
-        String filePath = file.getAbsolutePath();
-        FileInputStream stream = new FileInputStream(filePath);
+        String mimeType = getTypeForFile(file);
+        if (!MetadataReader.isSupportedMimeType(mimeType)) {
+            return null;
+        }
 
+        InputStream stream = null;
         try {
-            return getDocumentMetadataFromStream(stream, getTypeForFile(file));
+            Bundle metadata = new Bundle();
+            stream = new FileInputStream(file.getAbsolutePath());
+            MetadataReader.getMetadata(metadata, stream, mimeType, null);
+            return metadata;
         } catch (IOException e) {
             Log.e(TAG, "An error occurred retrieving the metadata", e);
+            return null;
         } finally {
             IoUtils.closeQuietly(stream);
         }
-
-        return null;
     }
 
     protected final List<String> findDocumentPath(File parent, File doc)
@@ -502,7 +508,7 @@ public abstract class FileSystemProvider extends DocumentsProvider {
     }
 
     protected boolean typeSupportsMetadata(String mimeType) {
-        return MIMETYPE_JPG.equals(mimeType) || MIMETYPE_JPEG.equals(mimeType);
+        return MetadataReader.isSupportedMimeType(mimeType);
     }
 
     private static String getTypeForName(String name) {
diff --git a/packages/MtpDocumentsProvider/src/com/android/mtp/MtpDatabase.java b/packages/MtpDocumentsProvider/src/com/android/mtp/MtpDatabase.java
index 9b5982b96e31..f243b51d6769 100644
--- a/packages/MtpDocumentsProvider/src/com/android/mtp/MtpDatabase.java
+++ b/packages/MtpDocumentsProvider/src/com/android/mtp/MtpDatabase.java
@@ -34,6 +34,7 @@ import android.mtp.MtpConstants;
 import android.mtp.MtpObjectInfo;
 import android.net.Uri;
 import android.provider.DocumentsContract;
+import android.provider.MetadataReader;
 import android.provider.DocumentsContract.Document;
 import android.provider.DocumentsContract.Root;
 
@@ -900,6 +901,9 @@ class MtpDatabase {
                 protectionState == MtpConstants.PROTECTION_STATUS_NONE) {
             flag |= Document.FLAG_DIR_SUPPORTS_CREATE;
         }
+        if (MetadataReader.isSupportedMimeType(mimeType)) {
+            flag |= Document.FLAG_SUPPORTS_METADATA;
+        }
         if (thumbnailSize > 0) {
             flag |= Document.FLAG_SUPPORTS_THUMBNAIL;
         }
diff --git a/packages/MtpDocumentsProvider/src/com/android/mtp/MtpDocumentsProvider.java b/packages/MtpDocumentsProvider/src/com/android/mtp/MtpDocumentsProvider.java
index eb2d8aa71955..8c8116bd342a 100644
--- a/packages/MtpDocumentsProvider/src/com/android/mtp/MtpDocumentsProvider.java
+++ b/packages/MtpDocumentsProvider/src/com/android/mtp/MtpDocumentsProvider.java
@@ -16,6 +16,7 @@
 
 package com.android.mtp;
 
+import android.annotation.Nullable;
 import android.content.ContentResolver;
 import android.content.ContentValues;
 import android.content.Context;
@@ -37,11 +38,12 @@ import android.os.FileUtils;
 import android.os.ParcelFileDescriptor;
 import android.os.ProxyFileDescriptorCallback;
 import android.os.storage.StorageManager;
+import android.provider.DocumentsContract;
 import android.provider.DocumentsContract.Document;
 import android.provider.DocumentsContract.Path;
 import android.provider.DocumentsContract.Root;
-import android.provider.DocumentsContract;
 import android.provider.DocumentsProvider;
+import android.provider.MetadataReader;
 import android.provider.Settings;
 import android.system.ErrnoException;
 import android.system.OsConstants;
@@ -50,14 +52,16 @@ import android.util.Log;
 import com.android.internal.annotations.GuardedBy;
 import com.android.internal.annotations.VisibleForTesting;
 
+import libcore.io.IoUtils;
+
 import java.io.FileNotFoundException;
 import java.io.IOException;
+import java.io.InputStream;
 import java.util.HashMap;
 import java.util.LinkedList;
 import java.util.List;
 import java.util.Map;
 import java.util.concurrent.TimeoutException;
-import libcore.io.IoUtils;
 
 /**
  * DocumentsProvider for MTP devices.
@@ -107,7 +111,7 @@ public class MtpDocumentsProvider extends DocumentsProvider {
         mResources = getContext().getResources();
         mMtpManager = new MtpManager(getContext());
         mResolver = getContext().getContentResolver();
-        mDeviceToolkits = new HashMap<Integer, DeviceToolkit>();
+        mDeviceToolkits = new HashMap<>();
         mDatabase = new MtpDatabase(getContext(), MtpDatabaseConstants.FLAG_DATABASE_IN_FILE);
         mRootScanner = new RootScanner(mResolver, mMtpManager, mDatabase);
         mIntentSender = new ServiceIntentSender(getContext());
@@ -151,7 +155,7 @@ public class MtpDocumentsProvider extends DocumentsProvider {
         mResources = resources;
         mMtpManager = mtpManager;
         mResolver = resolver;
-        mDeviceToolkits = new HashMap<Integer, DeviceToolkit>();
+        mDeviceToolkits = new HashMap<>();
         mDatabase = database;
         mRootScanner = new RootScanner(mResolver, mMtpManager, mDatabase);
         mIntentSender = intentSender;
@@ -548,6 +552,29 @@ public class MtpDocumentsProvider extends DocumentsProvider {
         }
     }
 
+    @Override
+    public @Nullable Bundle getDocumentMetadata(String docId) throws FileNotFoundException {
+        String mimeType = getDocumentType(docId);
+
+        if (!MetadataReader.isSupportedMimeType(mimeType)) {
+            return null;
+        }
+
+        InputStream stream = null;
+        try {
+            stream = new ParcelFileDescriptor.AutoCloseInputStream(
+                    openDocument(docId, "r", null));
+            Bundle metadata = new Bundle();
+            MetadataReader.getMetadata(metadata, stream, mimeType, null);
+            return metadata;
+        } catch (IOException e) {
+            Log.e(TAG, "An error occurred retrieving the metadata", e);
+            return null;
+        } finally {
+            IoUtils.closeQuietly(stream);
+        }
+    }
+
     void openDevice(int deviceId) throws IOException {
         synchronized (mDeviceListLock) {
             if (mDeviceToolkits.containsKey(deviceId)) {
diff --git a/packages/MtpDocumentsProvider/tests/src/com/android/mtp/MtpDatabaseTest.java b/packages/MtpDocumentsProvider/tests/src/com/android/mtp/MtpDatabaseTest.java
index 7fe6cb963522..32b169e6fa9f 100644
--- a/packages/MtpDocumentsProvider/tests/src/com/android/mtp/MtpDatabaseTest.java
+++ b/packages/MtpDocumentsProvider/tests/src/com/android/mtp/MtpDatabaseTest.java
@@ -237,7 +237,8 @@ public class MtpDatabaseTest extends AndroidTestCase {
         assertEquals(
                 COLUMN_FLAGS,
                 DocumentsContract.Document.FLAG_SUPPORTS_DELETE |
-                DocumentsContract.Document.FLAG_SUPPORTS_WRITE,
+                DocumentsContract.Document.FLAG_SUPPORTS_WRITE |
+                DocumentsContract.Document.FLAG_SUPPORTS_METADATA,
                 cursor.getInt(9));
         assertEquals(2 * 1024 * 1024, getInt(cursor, COLUMN_SIZE));
         assertEquals(
diff --git a/packages/MtpDocumentsProvider/tests/src/com/android/mtp/MtpDocumentsProviderTest.java b/packages/MtpDocumentsProvider/tests/src/com/android/mtp/MtpDocumentsProviderTest.java
index 3fa5eb581ef7..65c86dfb6d4c 100644
--- a/packages/MtpDocumentsProvider/tests/src/com/android/mtp/MtpDocumentsProviderTest.java
+++ b/packages/MtpDocumentsProvider/tests/src/com/android/mtp/MtpDocumentsProviderTest.java
@@ -329,7 +329,8 @@ public class MtpDocumentsProviderTest extends AndroidTestCase {
         assertEquals(
                 DocumentsContract.Document.FLAG_SUPPORTS_DELETE |
                 DocumentsContract.Document.FLAG_SUPPORTS_WRITE |
-                DocumentsContract.Document.FLAG_SUPPORTS_THUMBNAIL,
+                DocumentsContract.Document.FLAG_SUPPORTS_THUMBNAIL |
+                DocumentsContract.Document.FLAG_SUPPORTS_METADATA,
                 cursor.getInt(4));
         assertEquals(1024 * 1024 * 5, cursor.getInt(5));
     }
@@ -474,7 +475,8 @@ public class MtpDocumentsProviderTest extends AndroidTestCase {
         assertEquals("image/jpeg", cursor.getString(1));
         assertEquals("image.jpg", cursor.getString(2));
         assertEquals(0, cursor.getLong(3));
-        assertEquals(Document.FLAG_SUPPORTS_THUMBNAIL, cursor.getInt(4));
+        assertEquals(Document.FLAG_SUPPORTS_THUMBNAIL
+                | Document.FLAG_SUPPORTS_METADATA, cursor.getInt(4));
         assertEquals(1024 * 1024 * 5, cursor.getInt(5));
 
         cursor.close();