1 // Copyright 2013 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 #include "media/blink/cache_util.h"
6
7 #include <string>
8
9 #include "base/strings/string_number_conversions.h"
10 #include "base/strings/string_util.h"
11 #include "base/time/time.h"
12 #include "net/http/http_util.h"
13 #include "net/http/http_version.h"
14 #include "third_party/WebKit/public/platform/WebCString.h"
15 #include "third_party/WebKit/public/platform/WebString.h"
16 #include "third_party/WebKit/public/platform/WebURLResponse.h"
17
18 using base::Time;
19 using base::TimeDelta;
20 using net::HttpVersion;
21 using blink::WebURLResponse;
22
23 namespace media {
24
25 enum { kHttpOK = 200, kHttpPartialContent = 206 };
26
GetReasonsForUncacheability(const WebURLResponse & response)27 uint32 GetReasonsForUncacheability(const WebURLResponse& response) {
28 uint32 reasons = 0;
29 const int code = response.httpStatusCode();
30 const int version = response.httpVersion();
31 const HttpVersion http_version =
32 version == WebURLResponse::HTTP_1_1 ? HttpVersion(1, 1) :
33 version == WebURLResponse::HTTP_1_0 ? HttpVersion(1, 0) :
34 version == WebURLResponse::HTTP_0_9 ? HttpVersion(0, 9) :
35 HttpVersion();
36 if (code != kHttpOK && code != kHttpPartialContent)
37 reasons |= kNoData;
38 if (http_version < HttpVersion(1, 1) && code == kHttpPartialContent)
39 reasons |= kPre11PartialResponse;
40 if (code == kHttpPartialContent &&
41 !net::HttpUtil::HasStrongValidators(
42 http_version,
43 response.httpHeaderField("etag").utf8(),
44 response.httpHeaderField("Last-Modified").utf8(),
45 response.httpHeaderField("Date").utf8())) {
46 reasons |= kNoStrongValidatorOnPartialResponse;
47 }
48
49 std::string cache_control_header =
50 response.httpHeaderField("cache-control").utf8();
51 base::StringToLowerASCII(&cache_control_header);
52 if (cache_control_header.find("no-cache") != std::string::npos)
53 reasons |= kNoCache;
54 if (cache_control_header.find("no-store") != std::string::npos)
55 reasons |= kNoStore;
56 if (cache_control_header.find("must-revalidate") != std::string::npos)
57 reasons |= kHasMustRevalidate;
58
59 const TimeDelta kMinimumAgeForUsefulness =
60 TimeDelta::FromSeconds(3600); // Arbitrary value.
61
62 const char kMaxAgePrefix[] = "max-age=";
63 const size_t kMaxAgePrefixLen = arraysize(kMaxAgePrefix) - 1;
64 if (cache_control_header.substr(0, kMaxAgePrefixLen) == kMaxAgePrefix) {
65 int64 max_age_seconds;
66 base::StringToInt64(
67 base::StringPiece(cache_control_header.begin() + kMaxAgePrefixLen,
68 cache_control_header.end()),
69 &max_age_seconds);
70 if (TimeDelta::FromSeconds(max_age_seconds) < kMinimumAgeForUsefulness)
71 reasons |= kShortMaxAge;
72 }
73
74 Time date;
75 Time expires;
76 if (Time::FromString(response.httpHeaderField("Date").utf8().data(), &date) &&
77 Time::FromString(response.httpHeaderField("Expires").utf8().data(),
78 &expires) &&
79 date > Time() && expires > Time() &&
80 (expires - date) < kMinimumAgeForUsefulness) {
81 reasons |= kExpiresTooSoon;
82 }
83
84 return reasons;
85 }
86
87 } // namespace media
88