1/*
2 * Copyright (C) 2011 The Android Open Source Project
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 *      http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16
17package com.android.layoutlib.bridge.impl;
18
19
20import org.xmlpull.v1.XmlPullParser;
21import org.xmlpull.v1.XmlPullParserException;
22
23import android.annotation.NonNull;
24import android.annotation.Nullable;
25
26import java.io.BufferedInputStream;
27import java.io.ByteArrayInputStream;
28import java.io.File;
29import java.io.FileInputStream;
30import java.io.FileNotFoundException;
31import java.io.IOException;
32import java.io.InputStream;
33
34/**
35 * A factory for {@link XmlPullParser}.
36 *
37 */
38public class ParserFactory {
39
40    public final static boolean LOG_PARSER = false;
41
42    // Used to get a new XmlPullParser from the client.
43    @Nullable
44    private static com.android.ide.common.rendering.api.ParserFactory sParserFactory;
45
46    public static void setParserFactory(
47            @Nullable com.android.ide.common.rendering.api.ParserFactory parserFactory) {
48        sParserFactory = parserFactory;
49    }
50
51    @NonNull
52    public static XmlPullParser create(@NonNull File f)
53            throws XmlPullParserException, FileNotFoundException {
54        return create(f, false);
55    }
56
57    public static XmlPullParser create(@NonNull File f, boolean isLayout)
58      throws XmlPullParserException, FileNotFoundException {
59        InputStream stream = new FileInputStream(f);
60        return create(stream, f.getName(), f.length(), isLayout);
61    }
62    @NonNull
63    public static XmlPullParser create(@NonNull InputStream stream, @Nullable String name)
64        throws XmlPullParserException {
65        return create(stream, name, -1, false);
66    }
67
68    @NonNull
69    private static XmlPullParser create(@NonNull InputStream stream, @Nullable String name,
70            long size, boolean isLayout) throws XmlPullParserException {
71        XmlPullParser parser = instantiateParser(name);
72
73        stream = readAndClose(stream, name, size);
74
75        parser.setInput(stream, null);
76        if (isLayout) {
77            try {
78                return new LayoutParserWrapper(parser).peekTillLayoutStart();
79            } catch (IOException e) {
80                throw new XmlPullParserException(null, parser, e);
81            }
82        }
83        return parser;
84    }
85
86    @NonNull
87    public static XmlPullParser instantiateParser(@Nullable String name)
88            throws XmlPullParserException {
89        if (sParserFactory == null) {
90            throw new XmlPullParserException("ParserFactory not initialized.");
91        }
92        XmlPullParser parser = sParserFactory.createParser(name);
93        parser.setFeature(XmlPullParser.FEATURE_PROCESS_NAMESPACES, true);
94        return parser;
95    }
96
97    @NonNull
98    private static InputStream readAndClose(@NonNull InputStream stream, @Nullable String name,
99            long size) throws XmlPullParserException {
100        // just a sanity check. It's doubtful we'll have such big files!
101        if (size > Integer.MAX_VALUE) {
102            throw new XmlPullParserException("File " + name + " is too big to be parsed");
103        }
104        int intSize = (int) size;
105
106        // create a buffered reader to facilitate reading.
107        BufferedInputStream bufferedStream = new BufferedInputStream(stream);
108        try {
109            int avail;
110            if (intSize != -1) {
111                avail = intSize;
112            } else {
113                // get the size to read.
114                avail = bufferedStream.available();
115            }
116
117            // create the initial buffer and read it.
118            byte[] buffer = new byte[avail];
119            int read = stream.read(buffer);
120
121            // this is the easy case.
122            if (read == intSize) {
123                return new ByteArrayInputStream(buffer);
124            }
125
126            // check if there is more to read (read() does not necessarily read all that
127            // available() returned!)
128            while ((avail = bufferedStream.available()) > 0) {
129                if (read + avail > buffer.length) {
130                    // just allocate what is needed. We're mostly reading small files
131                    // so it shouldn't be too problematic.
132                    byte[] moreBuffer = new byte[read + avail];
133                    System.arraycopy(buffer, 0, moreBuffer, 0, read);
134                    buffer = moreBuffer;
135                }
136
137                read += stream.read(buffer, read, avail);
138            }
139
140            // return a new stream encapsulating this buffer.
141            return new ByteArrayInputStream(buffer);
142
143        } catch (IOException e) {
144            throw new XmlPullParserException("Failed to read " + name, null, e);
145        } finally {
146            try {
147                bufferedStream.close();
148            } catch (IOException ignored) {
149            }
150        }
151    }
152}
153