1// Copyright (c) 2011 The Chromium Authors. All rights reserved.
2// Use of this source code is governed by a BSD-style license that can be
3// found in the LICENSE file.
4
5#ifndef NET_BASE_MIME_SNIFFER_H__
6#define NET_BASE_MIME_SNIFFER_H__
7
8#include <string>
9
10#include "net/base/net_export.h"
11
12class GURL;
13
14namespace net {
15
16// The maximum number of bytes used by any internal mime sniffing routine. May
17// be useful for callers to determine an efficient buffer size to pass to
18// |SniffMimeType|.
19// This must be updated if any internal sniffing routine needs more bytes.
20const int kMaxBytesToSniff = 1024;
21
22// Examine the URL and the mime_type and decide whether we should sniff a
23// replacement mime type from the content.
24//
25// @param url The URL from which we obtained the content.
26// @param mime_type The current mime type, e.g. from the Content-Type header.
27// @return Returns true if we should sniff the mime type.
28NET_EXPORT bool ShouldSniffMimeType(const GURL& url,
29                                    const std::string& mime_type);
30
31// Guess a mime type from the first few bytes of content an its URL.  Always
32// assigns |result| with its best guess of a mime type.
33//
34// @param content A buffer containing the bytes to sniff.
35// @param content_size The number of bytes in the |content| buffer.
36// @param url The URL from which we obtained this content.
37// @param type_hint The current mime type, e.g. from the Content-Type header.
38// @param result Address at which to place the sniffed mime type.
39// @return Returns true if we have enough content to guess the mime type.
40NET_EXPORT bool SniffMimeType(const char* content, size_t content_size,
41                              const GURL& url, const std::string& type_hint,
42                              std::string* result);
43
44// Attempt to identify a MIME type from the first few bytes of content only.
45// Uses a bigger set of media file searches than |SniffMimeType()|.
46// If finds a match, fills in |result| and returns true,
47// otherwise returns false.
48//
49// The caller should understand the security ramifications of trusting
50// uncontrolled data before accepting the results of this function.
51//
52// @param content A buffer containing the bytes to sniff.
53// @param content_size The number of bytes in the |content| buffer.
54// @param result Address at which to place the sniffed mime type.
55// @return Returns true if a MIME type match was found.
56NET_EXPORT bool SniffMimeTypeFromLocalData(const char* content,
57                                           size_t content_size,
58                                           std::string* result);
59
60}  // namespace net
61
62#endif  // NET_BASE_MIME_SNIFFER_H__
63