ImageProvider.java

/*
 * Copyright 2016 Hippo Seven
 *
 * 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.hippo.nimingban.content;

/*
 * Created by Hippo on 11/11/2016.
 */

import android.content.ContentProvider;
import android.content.ContentResolver;
import android.content.ContentValues;
import android.database.Cursor;
import android.database.MatrixCursor;
import android.net.Uri;
import android.os.ParcelFileDescriptor;
import android.provider.MediaStore;
import android.provider.OpenableColumns;
import android.support.annotation.NonNull;
import android.support.annotation.Nullable;
import android.webkit.MimeTypeMap;

import com.hippo.nimingban.util.Settings;
import com.hippo.unifile.UniFile;

import java.io.FileNotFoundException;
import java.util.List;

public class ImageProvider extends ContentProvider {

    private static final String AUTHORITY = "com.hippo.nimingban.image";

    private static final String[] COLUMNS = {
            OpenableColumns.DISPLAY_NAME, OpenableColumns.SIZE };

    @Override
    public boolean onCreate() {
        return true;
    }

    @Nullable
    @Override
    public Cursor query(@NonNull Uri uri, String[] projection,
            String selection, String[] selectionArgs, String sortOrder) {
        final UniFile file = getFileForUri(uri);
        if (file == null) {
            return null;
        }

        if (projection == null) {
            projection = COLUMNS;
        }

        String[] cols = new String[projection.length];
        Object[] values = new Object[projection.length];
        int i = 0;
        for (String col : projection) {
            if (OpenableColumns.DISPLAY_NAME.equals(col)) {
                cols[i] = OpenableColumns.DISPLAY_NAME;
                values[i++] = file.getName();
            } else if (OpenableColumns.SIZE.equals(col)) {
                cols[i] = OpenableColumns.SIZE;
                values[i++] = file.length();
            } else if (MediaStore.MediaColumns.DATA.equals(col)) {
                Uri originUri = file.getUri();
                if (ContentResolver.SCHEME_FILE.equals(originUri.getScheme())) {
                    cols[i] = MediaStore.MediaColumns.DATA;
                    values[i++] = file.getUri().getPath();
                } else {
                    // TODO handle document tree url
                }
            }
        }

        cols = copyOf(cols, i);
        values = copyOf(values, i);

        final MatrixCursor cursor = new MatrixCursor(cols, 1);
        cursor.addRow(values);
        return cursor;
    }

    @Nullable
    @Override
    public String getType(@NonNull Uri uri) {
        final UniFile file = getFileForUri(uri);
        if (file != null) {
            final String name = file.getUri().getPath();
            if (name != null) {
                final int lastDot = name.lastIndexOf('.');
                if (lastDot >= 0) {
                    final String extension = name.substring(lastDot + 1);
                    final String mime = MimeTypeMap.getSingleton().getMimeTypeFromExtension(extension);
                    if (mime != null) {
                        return mime;
                    }
                }
            }
        }

        return "application/octet-stream";
    }

    @Nullable
    @Override
    public Uri insert(@NonNull Uri uri, ContentValues values) {
        throw new UnsupportedOperationException();
    }

    @Override
    public int delete(@NonNull Uri uri, String selection, String[] selectionArgs) {
        throw new UnsupportedOperationException();
    }

    @Override
    public int update(@NonNull Uri uri, ContentValues values, String selection, String[] selectionArgs) {
        throw new UnsupportedOperationException();
    }

    @Override
    public ParcelFileDescriptor openFile(@NonNull Uri uri, @NonNull String mode) throws FileNotFoundException {
        UniFile file = getFileForUri(uri);
        if (file != null) {
            ParcelFileDescriptor pfd = getContext().getContentResolver().openFileDescriptor(file.getUri(), mode);
            if (pfd != null) {
                return pfd;
            }
        }
        throw new FileNotFoundException("Can't find " + uri);
    }

    public UniFile getFileForUri(Uri uri) {
        // Check authority
        if (!ContentResolver.SCHEME_CONTENT.equals(uri.getScheme()) ||
                !AUTHORITY.equals(uri.getAuthority())) {
            return null;
        }

        // Get dir
        UniFile dir = Settings.getImageSaveLocation();
        if (dir == null) {
            return null;
        }

        // Get filename
        List<String> path = uri.getPathSegments();
        if (path == null || path.size() != 1) {
            return null;
        }

        return dir.findFile(path.get(0));
    }

    public static Uri buildUri(String filename) {
        return new Uri.Builder()
                .scheme(ContentResolver.SCHEME_CONTENT)
                .authority(AUTHORITY)
                .appendPath(filename)
                .build();
    }

    private static String[] copyOf(String[] original, int newLength) {
        final String[] result = new String[newLength];
        System.arraycopy(original, 0, result, 0, newLength);
        return result;
    }

    private static Object[] copyOf(Object[] original, int newLength) {
        final Object[] result = new Object[newLength];
        System.arraycopy(original, 0, result, 0, newLength);
        return result;
    }
}