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// Copyright 2013 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#include "content/renderer/media/cache_util.h"
#include <string>
#include "base/strings/string_number_conversions.h"
#include "base/strings/string_util.h"
#include "base/time/time.h"
#include "net/http/http_util.h"
#include "net/http/http_version.h"
#include "third_party/WebKit/public/platform/WebCString.h"
#include "third_party/WebKit/public/platform/WebString.h"
#include "third_party/WebKit/public/platform/WebURLResponse.h"
using base::Time;
using base::TimeDelta;
using net::HttpVersion;
using WebKit::WebURLResponse;
namespace content {
enum { kHttpOK = 200, kHttpPartialContent = 206 };
uint32 GetReasonsForUncacheability(const WebURLResponse& response) {
uint32 reasons = 0;
const int code = response.httpStatusCode();
const int version = response.httpVersion();
const HttpVersion http_version =
version == WebURLResponse::HTTP_1_1 ? HttpVersion(1, 1) :
version == WebURLResponse::HTTP_1_0 ? HttpVersion(1, 0) :
version == WebURLResponse::HTTP_0_9 ? HttpVersion(0, 9) :
HttpVersion();
if (code != kHttpOK && code != kHttpPartialContent)
reasons |= kNoData;
if (http_version < HttpVersion(1, 1) && code == kHttpPartialContent)
reasons |= kPre11PartialResponse;
if (code == kHttpPartialContent &&
!net::HttpUtil::HasStrongValidators(
http_version,
response.httpHeaderField("etag").utf8(),
response.httpHeaderField("Last-Modified").utf8(),
response.httpHeaderField("Date").utf8())) {
reasons |= kNoStrongValidatorOnPartialResponse;
}
std::string cache_control_header =
response.httpHeaderField("cache-control").utf8();
StringToLowerASCII(&cache_control_header);
if (cache_control_header.find("no-cache") != std::string::npos)
reasons |= kNoCache;
if (cache_control_header.find("no-store") != std::string::npos)
reasons |= kNoStore;
if (cache_control_header.find("must-revalidate") != std::string::npos)
reasons |= kHasMustRevalidate;
const TimeDelta kMinimumAgeForUsefulness =
TimeDelta::FromSeconds(3600); // Arbitrary value.
const char kMaxAgePrefix[] = "max-age=";
const size_t kMaxAgePrefixLen = arraysize(kMaxAgePrefix) - 1;
if (cache_control_header.substr(0, kMaxAgePrefixLen) == kMaxAgePrefix) {
int64 max_age_seconds;
base::StringToInt64(
base::StringPiece(cache_control_header.begin() + kMaxAgePrefixLen,
cache_control_header.end()),
&max_age_seconds);
if (TimeDelta::FromSeconds(max_age_seconds) < kMinimumAgeForUsefulness)
reasons |= kShortMaxAge;
}
Time date;
Time expires;
if (Time::FromString(response.httpHeaderField("Date").utf8().data(), &date) &&
Time::FromString(response.httpHeaderField("Expires").utf8().data(),
&expires) &&
date > Time() && expires > Time() &&
(expires - date) < kMinimumAgeForUsefulness) {
reasons |= kExpiresTooSoon;
}
return reasons;
}
} // namespace content
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