packages/DocumentsUI/src/com/android/documentsui/RootsCache.java

/*
 * 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.documentsui;

import static com.android.documentsui.DocumentsActivity.TAG;

import android.content.ContentProviderClient;
import android.content.ContentResolver;
import android.content.Context;
import android.content.Intent;
import android.content.pm.PackageManager;
import android.content.pm.ProviderInfo;
import android.content.pm.ResolveInfo;
import android.database.Cursor;
import android.graphics.drawable.Drawable;
import android.net.Uri;
import android.provider.DocumentsContract;
import android.provider.DocumentsContract.Document;
import android.provider.DocumentsContract.Root;
import android.util.Log;

import com.android.documentsui.DocumentsActivity.State;
import com.android.documentsui.model.RootInfo;
import com.android.internal.annotations.GuardedBy;
import com.android.internal.util.Objects;
import com.google.android.collect.Lists;

import libcore.io.IoUtils;

import java.util.ArrayList;
import java.util.List;

/**
 * Cache of known storage backends and their roots.
 */
public class RootsCache {

    // TODO: cache roots in local provider to avoid spinning up backends
    // TODO: root updates should trigger UI refresh

    private static final boolean RECENTS_ENABLED = true;

    private final Context mContext;

    public List<RootInfo> mRoots = Lists.newArrayList();

    private RootInfo mRecentsRoot;

    public RootsCache(Context context) {
        mContext = context;
        update();
    }

    /**
     * Gather roots from all known storage providers.
     */
    @GuardedBy("ActivityThread")
    public void update() {
        mRoots.clear();

        if (RECENTS_ENABLED) {
            // Create special root for recents
            final RootInfo root = new RootInfo();
            root.rootType = Root.ROOT_TYPE_SHORTCUT;
            root.icon = R.drawable.ic_dir;
            root.flags = Root.FLAG_LOCAL_ONLY | Root.FLAG_SUPPORTS_CREATE;
            root.title = mContext.getString(R.string.root_recent);
            root.availableBytes = -1;

            mRoots.add(root);
            mRecentsRoot = root;
        }

        // Query for other storage backends
        final ContentResolver resolver = mContext.getContentResolver();
        final PackageManager pm = mContext.getPackageManager();
        final List<ProviderInfo> providers = pm.queryContentProviders(
                null, -1, PackageManager.GET_META_DATA);
        for (ProviderInfo info : providers) {
            if (info.metaData != null && info.metaData.containsKey(
                    DocumentsContract.META_DATA_DOCUMENT_PROVIDER)) {

                // TODO: remove deprecated customRoots flag
                // TODO: populate roots on background thread, and cache results
                final Uri rootsUri = DocumentsContract.buildRootsUri(info.authority);
                final ContentProviderClient client = resolver
                        .acquireUnstableContentProviderClient(info.authority);
                Cursor cursor = null;
                try {
                    cursor = client.query(rootsUri, null, null, null, null);
                    while (cursor.moveToNext()) {
                        final RootInfo root = RootInfo.fromRootsCursor(info.authority, cursor);
                        mRoots.add(root);
                    }
                } catch (Exception e) {
                    Log.w(TAG, "Failed to load some roots from " + info.authority + ": " + e);
                } finally {
                    IoUtils.closeQuietly(cursor);
                    ContentProviderClient.closeQuietly(client);
                }
            }
        }
    }

    @Deprecated
    public RootInfo findRoot(Uri uri) {
        final String authority = uri.getAuthority();
        final String docId = DocumentsContract.getDocumentId(uri);
        for (RootInfo root : mRoots) {
            if (Objects.equal(root.authority, authority) && Objects.equal(root.documentId, docId)) {
                return root;
            }
        }
        return null;
    }

    @GuardedBy("ActivityThread")
    public RootInfo getRoot(String authority, String rootId) {
        for (RootInfo root : mRoots) {
            if (Objects.equal(root.authority, authority) && Objects.equal(root.rootId, rootId)) {
                return root;
            }
        }
        return null;
    }

    @GuardedBy("ActivityThread")
    public RootInfo getRecentsRoot() {
        return mRecentsRoot;
    }

    @GuardedBy("ActivityThread")
    public boolean isRecentsRoot(RootInfo root) {
        return mRecentsRoot == root;
    }

    @GuardedBy("ActivityThread")
    public List<RootInfo> getRoots() {
        return mRoots;
    }

    /**
     * Flags that declare explicit content types.
     */
    private static final int FLAGS_CONTENT_MASK = Root.FLAG_PROVIDES_IMAGES
            | Root.FLAG_PROVIDES_AUDIO | Root.FLAG_PROVIDES_VIDEO;

    @GuardedBy("ActivityThread")
    public List<RootInfo> getMatchingRoots(State state) {

        // Determine acceptable content flags
        int includeFlags = 0;
        for (String acceptMime : state.acceptMimes) {
            final String[] type = acceptMime.split("/");
            if (type.length != 2) continue;

            if ("image".equals(type[0])) {
                includeFlags |= Root.FLAG_PROVIDES_IMAGES;
            } else if ("audio".equals(type[0])) {
                includeFlags |= Root.FLAG_PROVIDES_AUDIO;
            } else if ("video".equals(type[0])) {
                includeFlags |= Root.FLAG_PROVIDES_VIDEO;
            } else if ("*".equals(type[0])) {
                includeFlags |= Root.FLAG_PROVIDES_IMAGES | Root.FLAG_PROVIDES_AUDIO
                        | Root.FLAG_PROVIDES_VIDEO;
            }
        }

        ArrayList<RootInfo> matching = Lists.newArrayList();
        for (RootInfo root : mRoots) {
            final boolean supportsCreate = (root.flags & Root.FLAG_SUPPORTS_CREATE) != 0;
            final boolean advanced = (root.flags & Root.FLAG_ADVANCED) != 0;
            final boolean localOnly = (root.flags & Root.FLAG_LOCAL_ONLY) != 0;

            // Exclude read-only devices when creating
            if (state.action == State.ACTION_CREATE && !supportsCreate) continue;
            // Exclude advanced devices when not requested
            if (!state.showAdvanced && advanced) continue;
            // Exclude non-local devices when local only
            if (state.localOnly && !localOnly) continue;

            if ((root.flags & FLAGS_CONTENT_MASK) != 0) {
                // This root offers specific content, so only include if the
                // caller asked for that content type.
                if ((root.flags & includeFlags) == 0) {
                    // Sorry, no overlap.
                    continue;
                }
            }

            matching.add(root);
        }
        return matching;
    }

    @GuardedBy("ActivityThread")
    public static Drawable resolveDocumentIcon(Context context, String mimeType) {
        if (Document.MIME_TYPE_DIR.equals(mimeType)) {
            return context.getResources().getDrawable(R.drawable.ic_dir);
        } else {
            final PackageManager pm = context.getPackageManager();
            final Intent intent = new Intent(Intent.ACTION_VIEW);
            intent.setType(mimeType);

            final ResolveInfo activityInfo = pm.resolveActivity(
                    intent, PackageManager.MATCH_DEFAULT_ONLY);
            if (activityInfo != null) {
                return activityInfo.loadIcon(pm);
            } else {
                return null;
            }
        }
    }
}