cordova-plugin-printer/src/android/AssetUtil.java

/*
 Licensed to the Apache Software Foundation (ASF) under one
 or more contributor license agreements.  See the NOTICE file
 distributed with this work for additional information
 regarding copyright ownership.  The ASF licenses this file
 to you 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 de.appplant.cordova.plugin.printer;

import android.content.Context;
import android.content.res.AssetManager;
import android.content.res.Resources;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.support.annotation.NonNull;
import android.support.annotation.Nullable;
import android.util.Base64;

import java.io.ByteArrayInputStream;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;

class AssetUtil {

    // List of supported content types
    enum ContentType { PLAIN, HTML, IMAGE, PDF, SELF }

    // Application context
    private final @NonNull Context context;

    /**
     * Initializes the asset utils.
     *
     * @param ctx The application context.
     */
    AssetUtil (@NonNull Context ctx) {
        this.context = ctx;
    }

    /**
     * Returns the content type for the file referenced by its uri.
     *
     * @param path The path to check.
     *
     * @return The content type even the file does not exist.
     */
    static @NonNull ContentType getContentType (@Nullable String path)
    {
        ContentType type = ContentType.PLAIN;

        if (path == null || path.isEmpty())
        {
            type = ContentType.SELF;
        }
        else if (path.charAt(0) == '<')
        {
            type = ContentType.HTML;
        }
        else if (path.matches("^[a-z]+://.+"))
        {
            return path.endsWith(".pdf") ? ContentType.PDF : ContentType.IMAGE;
        }

        return type;
    }

    /**
     * Opens a file://, res:// or base64:// Uri as a stream.
     *
     * @param path The file path to decode.
     *
     * @return An open IO stream or null if the file does not exist.
     */
    @Nullable InputStream open (@NonNull String path)
    {
        InputStream stream = null;

        if (path.startsWith("res:"))
        {
            stream = openResource(path);
        }
        else if (path.startsWith("file:///"))
        {
            stream = openFile(path);
        }
        else if (path.startsWith("file://"))
        {
            stream = openAsset(path);
        }
        else if (path.startsWith("base64:"))
        {
            stream = openBase64(path);
        }

        return stream;
    }

    /**
     * Decodes a file://, res:// or base64:// Uri to bitmap.
     *
     * @param path The file path to decode.
     *
     * @return A bitmap or null if the path is not valid
     */
    @Nullable Bitmap decode (@NonNull String path)
    {
        Bitmap bitmap;

        if (path.startsWith("res:"))
        {
            bitmap = decodeResource(path);
        }
        else if (path.startsWith("file:///"))
        {
            bitmap = decodeFile(path);
        }
        else if (path.startsWith("file://"))
        {
            bitmap = decodeAsset(path);
        }
        else if (path.startsWith("base64:"))
        {
            bitmap = decodeBase64(path);
        }
        else {
            bitmap = BitmapFactory.decodeFile(path);
        }

        return bitmap;
    }

    /**
     * Copies content of input stream to output stream.
     *
     * @param input  The readable input stream.
     * @param output The writable output stream.
     *
     * @throws IOException
     */
    static void copy (@NonNull InputStream input,
                      @NonNull OutputStream output) throws IOException
    {
        byte[] buf = new byte[1024];
        int bytesRead;

        while ((bytesRead = input.read(buf)) > 0) {
            output.write(buf, 0, bytesRead);
        }

        output.close();
        input.close();
    }

    /**
     * Opens an file given as a file:/// path.
     *
     * @param path The path to the file.
     *
     * @return An open IO stream or null if the file does not exist.
     */
    private @Nullable InputStream openFile (@NonNull String path)
    {
        String absPath = path.substring(7);

        try {
            return new FileInputStream(absPath);
        } catch (FileNotFoundException e) {
            return null;
        }
    }

    /**
     * Decodes an file given as a file:/// path to a bitmap.
     *
     * @param path The path to the file.
     *
     * @return A bitmap or null if the path is not valid
     */
    private @Nullable Bitmap decodeFile (@NonNull String path)
    {
        String absPath = path.substring(7);

        return BitmapFactory.decodeFile(absPath);
    }

    /**
     * Opens an asset file given as a file:// path.
     *
     * @param path The path to the asset.
     *
     * @return An open IO stream or null if the file does not exist.
     */
    private @Nullable InputStream openAsset (@NonNull String path)
    {
        String resPath = path.replaceFirst("file:/", "www");

        try {
            return getAssets().open(resPath);
        } catch (Exception e) {
            return null;
        }
    }

    /**
     * Decodes an asset file given as a file:// path to a bitmap.
     *
     * @param path The path to the asset.
     *
     * @return A bitmap or null if the path is not valid
     */
    private @Nullable Bitmap decodeAsset (@NonNull String path)
    {
        InputStream stream  = openAsset(path);
        Bitmap bitmap;

        if (stream == null)
            return null;

        bitmap = BitmapFactory.decodeStream(stream);

        try {
            stream.close();
        } catch (IOException e) {
            // ignore
        }

        return bitmap;
    }

    /**
     * Opens a resource file given as a res:// path.
     *
     * @param path The path to the resource.
     *
     * @return An open IO stream or null if the file does not exist.
     */
    private @NonNull InputStream openResource (@NonNull String path)
    {
        String resPath = path.substring(6);
        int resId      = getResId(resPath);

        return getResources().openRawResource(resId);
    }

    /**
     * Decodes a resource given as a res:// path to a bitmap.
     *
     * @param path The path to the resource.
     *
     * @return A bitmap or null if the path is not valid
     */
    private @Nullable Bitmap decodeResource (@NonNull String path)
    {
        String data  = path.substring(9);
        byte[] bytes = Base64.decode(data, 0);

        return BitmapFactory.decodeByteArray(bytes, 0, bytes.length);
    }

    /**
     * Opens a resource file given as a res:// path.
     *
     * @param path The path to the resource.
     *
     * @return An open IO stream or null if the file does not exist.
     */
    private @NonNull InputStream openBase64 (@NonNull String path)
    {
        String data  = path.substring(9);
        byte[] bytes = Base64.decode(data, 0);

        return new ByteArrayInputStream(bytes);
    }

    /**
     * Decodes a resource given as a base64:// string to a bitmap.
     *
     * @param path The given relative path.
     *
     * @return A bitmap or null if the path is not valid
     */
    private @Nullable Bitmap decodeBase64 (@NonNull String path)
    {
        String data  = path.substring(9);
        byte[] bytes = Base64.decode(data, 0);

        return BitmapFactory.decodeByteArray(bytes, 0, bytes.length);
    }

    /**
     * Returns the resource ID for the given resource path.
     *
     * @return The resource ID for the given resource.
     */
    private int getResId (@NonNull String resPath)
    {
        Resources res   = getResources();
        String pkgName  = context.getPackageName();
        String dirName  = "drawable";
        String fileName = resPath;

        if (resPath.contains("/")) {
            dirName  = resPath.substring(0, resPath.lastIndexOf('/'));
            fileName = resPath.substring(resPath.lastIndexOf('/') + 1);
        }

        String resName = fileName.substring(0, fileName.lastIndexOf('.'));
        int resId      = res.getIdentifier(resName, dirName, pkgName);

        if (resId == 0) {
            resId = res.getIdentifier(resName, "mipmap", pkgName);
        }

        if (resId == 0) {
            resId = res.getIdentifier(resName, "drawable", pkgName);
        }

        return resId;
    }

    private AssetManager getAssets() {
        return context.getAssets();
    }

    private Resources getResources() {
        return context.getResources();
    }
}