External storage provider, document picker UI.

Continuing to flesh out storage backends by adding an external
storage document backend.  Still rough, but it can traverse files
and directories.

Early pass at OPEN/CREATE_DOC picker UI, which offers to traverse
any known storage backends.  Supports opening subdirectories and
returning a picked file.

Change-Id: Idc3554036b3816a93d9b465ee8a620746859d2ae

1 files changed, 204 insertions, 0 deletions

diff --git a/packages/ExternalStorageProvider/src/com/android/externalstorage/ExternalStorageProvider.java b/packages/ExternalStorageProvider/src/com/android/externalstorage/ExternalStorageProvider.java
new file mode 100644
index 0000000..f75e3bd
--- /dev/null
+++ b/packages/ExternalStorageProvider/src/com/android/externalstorage/ExternalStorageProvider.java
@@ -0,0 +1,204 @@
+/*
+ * Copyright (C) 2013 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 com.android.externalstorage;
+
+import android.content.ContentProvider;
+import android.content.ContentResolver;
+import android.content.ContentValues;
+import android.content.UriMatcher;
+import android.database.Cursor;
+import android.database.MatrixCursor;
+import android.net.Uri;
+import android.os.Environment;
+import android.os.ParcelFileDescriptor;
+import android.provider.BaseColumns;
+import android.provider.DocumentsContract;
+import android.provider.DocumentsContract.DocumentColumns;
+import android.webkit.MimeTypeMap;
+
+import com.android.internal.annotations.GuardedBy;
+import com.google.android.collect.Lists;
+
+import java.io.File;
+import java.io.FileNotFoundException;
+import java.util.ArrayList;
+
+public class ExternalStorageProvider extends ContentProvider {
+    private static final String TAG = "ExternalStorage";
+
+    private static final String AUTHORITY = "com.android.externalstorage";
+
+    // TODO: support searching
+    // TODO: support multiple storage devices
+    // TODO: persist GUIDs across launches
+
+    private static final UriMatcher sMatcher = new UriMatcher(UriMatcher.NO_MATCH);
+
+    private static final int URI_DOCS_ID = 1;
+    private static final int URI_DOCS_ID_CONTENTS = 2;
+    private static final int URI_SEARCH = 3;
+
+    static {
+        sMatcher.addURI(AUTHORITY, "docs/#", URI_DOCS_ID);
+        sMatcher.addURI(AUTHORITY, "docs/#/contents", URI_DOCS_ID_CONTENTS);
+        sMatcher.addURI(AUTHORITY, "search", URI_SEARCH);
+    }
+
+    @GuardedBy("mFiles")
+    private ArrayList<File> mFiles = Lists.newArrayList();
+
+    @Override
+    public boolean onCreate() {
+        mFiles.clear();
+        mFiles.add(Environment.getExternalStorageDirectory());
+        return true;
+    }
+
+    @Override
+    public Cursor query(Uri uri, String[] projection, String selection, String[] selectionArgs,
+            String sortOrder) {
+
+        // TODO: support custom projections
+        projection = new String[] {
+                BaseColumns._ID,
+                DocumentColumns.DISPLAY_NAME, DocumentColumns.SIZE, DocumentColumns.GUID,
+                DocumentColumns.MIME_TYPE, DocumentColumns.LAST_MODIFIED, DocumentColumns.FLAGS };
+
+        final MatrixCursor cursor = new MatrixCursor(projection);
+        switch (sMatcher.match(uri)) {
+            case URI_DOCS_ID: {
+                final int id = Integer.parseInt(uri.getPathSegments().get(1));
+                synchronized (mFiles) {
+                    includeFileLocked(cursor, id);
+                }
+                break;
+            }
+            case URI_DOCS_ID_CONTENTS: {
+                final int parentId = Integer.parseInt(uri.getPathSegments().get(1));
+                synchronized (mFiles) {
+                    final File parent = mFiles.get(parentId);
+                    for (File file : parent.listFiles()) {
+                        final int id = findOrCreateFileLocked(file);
+                        includeFileLocked(cursor, id);
+                    }
+                }
+                break;
+            }
+            default: {
+                cursor.close();
+                throw new UnsupportedOperationException("Unsupported Uri " + uri);
+            }
+        }
+
+        return cursor;
+    }
+
+    private int findOrCreateFileLocked(File file) {
+        int id = mFiles.indexOf(file);
+        if (id == -1) {
+            id = mFiles.size();
+            mFiles.add(file);
+        }
+        return id;
+    }
+
+    private void includeFileLocked(MatrixCursor cursor, int id) {
+        final File file = mFiles.get(id);
+        int flags = 0;
+
+        if (file.isDirectory() && file.canWrite()) {
+            flags |= DocumentsContract.FLAG_SUPPORTS_CREATE;
+        }
+        if (file.canWrite()) {
+            flags |= DocumentsContract.FLAG_SUPPORTS_RENAME;
+        }
+
+        final String mimeType = getTypeLocked(id);
+        if (mimeType.startsWith("image/")) {
+            flags |= DocumentsContract.FLAG_SUPPORTS_THUMBNAIL;
+        }
+
+        cursor.addRow(new Object[] {
+                id, file.getName(), file.length(), id, mimeType, file.lastModified(), flags });
+    }
+
+    @Override
+    public String getType(Uri uri) {
+        switch (sMatcher.match(uri)) {
+            case URI_DOCS_ID: {
+                final int id = Integer.parseInt(uri.getPathSegments().get(1));
+                synchronized (mFiles) {
+                    return getTypeLocked(id);
+                }
+            }
+            default: {
+                throw new UnsupportedOperationException("Unsupported Uri " + uri);
+            }
+        }
+    }
+
+    private String getTypeLocked(int id) {
+        final File file = mFiles.get(id);
+
+        if (file.isDirectory()) {
+            return DocumentsContract.MIME_TYPE_DIRECTORY;
+        }
+
+        final int lastDot = file.getName().lastIndexOf('.');
+        if (lastDot >= 0) {
+            final String extension = file.getName().substring(lastDot + 1);
+            final String mime = MimeTypeMap.getSingleton().getMimeTypeFromExtension(extension);
+            if (mime != null) {
+                return mime;
+            }
+        }
+
+        return "application/octet-stream";
+    }
+
+    @Override
+    public ParcelFileDescriptor openFile(Uri uri, String mode) throws FileNotFoundException {
+        switch (sMatcher.match(uri)) {
+            case URI_DOCS_ID: {
+                final int id = Integer.parseInt(uri.getPathSegments().get(1));
+                synchronized (mFiles) {
+                    final File file = mFiles.get(id);
+                    // TODO: turn into thumbnail
+                    return ParcelFileDescriptor.open(file, ContentResolver.modeToMode(uri, mode));
+                }
+            }
+            default: {
+                throw new UnsupportedOperationException("Unsupported Uri " + uri);
+            }
+        }
+    }
+
+    @Override
+    public Uri insert(Uri uri, ContentValues values) {
+        throw new UnsupportedOperationException();
+    }
+
+    @Override
+    public int update(Uri uri, ContentValues values, String selection, String[] selectionArgs) {
+        throw new UnsupportedOperationException();
+    }
+
+    @Override
+    public int delete(Uri uri, String selection, String[] selectionArgs) {
+        throw new UnsupportedOperationException();
+    }
+}