DataSource.h revision 66b0a35c9a4136a84c3f73b1b25fcb5220138b95 
1/*
2 * Copyright (C) 2009 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
17#ifndef DATA_SOURCE_H_
18
19#define DATA_SOURCE_H_
20
21#include <sys/types.h>
22
23#include <utils/Errors.h>
24#include <utils/List.h>
25#include <utils/RefBase.h>
26#include <utils/threads.h>
27
28namespace android {
29
30class String8;
31
32class DataSource : public RefBase {
33public:
34    enum Flags {
35        kWantsPrefetching = 1,
36    };
37
38    static sp<DataSource> CreateFromURI(const char *uri);
39
40    DataSource() {}
41
42    virtual status_t initCheck() const = 0;
43
44    virtual ssize_t readAt(off_t offset, void *data, size_t size) = 0;
45
46    // Convenience methods:
47    bool getUInt16(off_t offset, uint16_t *x);
48
49    // May return ERROR_UNSUPPORTED.
50    virtual status_t getSize(off_t *size);
51
52    virtual uint32_t flags() {
53        return 0;
54    }
55
56    ////////////////////////////////////////////////////////////////////////////
57
58    bool sniff(String8 *mimeType, float *confidence);
59
60    typedef bool (*SnifferFunc)(
61            const sp<DataSource> &source, String8 *mimeType, float *confidence);
62
63    static void RegisterSniffer(SnifferFunc func);
64    static void RegisterDefaultSniffers();
65
66protected:
67    virtual ~DataSource() {}
68
69private:
70    static Mutex gSnifferMutex;
71    static List<SnifferFunc> gSniffers;
72
73    DataSource(const DataSource &);
74    DataSource &operator=(const DataSource &);
75};
76
77}  // namespace android
78
79#endif  // DATA_SOURCE_H_
80