static double freshnessLifetime(ResourceResponse& response, double responseTimestamp)
{
#if !OS(ANDROID)
// On desktop, local files should be reloaded in case they change.
if (response.url().isLocalFile())
return 0;
#endif
// Cache other non-http / non-filesystem resources liberally.
if (!response.url().protocolIsInHTTPFamily()
&& !response.url().protocolIs("filesystem"))
return std::numeric_limits<double>::max();
// RFC2616 13.2.4
double maxAgeValue = response.cacheControlMaxAge();
if (std::isfinite(maxAgeValue))
return maxAgeValue;
double expiresValue = response.expires();
double dateValue = response.date();
double creationTime = std::isfinite(dateValue) ? dateValue : responseTimestamp;
if (std::isfinite(expiresValue))
return expiresValue - creationTime;
double lastModifiedValue = response.lastModified();
if (std::isfinite(lastModifiedValue))
return (creationTime - lastModifiedValue) * 0.1;
// If no cache headers are present, the specification leaves the decision to the UA. Other browsers seem to opt for 0.
return 0;
}
static double currentAge(const ResourceResponse& response, double responseTimestamp)
{
// RFC2616 13.2.3
// No compensation for latency as that is not terribly important in practice
double dateValue = response.date();
double apparentAge = std::isfinite(dateValue) ? std::max(0., responseTimestamp - dateValue) : 0;
double ageValue = response.age();
double correctedReceivedAge = std::isfinite(ageValue) ? std::max(apparentAge, ageValue) : apparentAge;
double residentTime = currentTime() - responseTimestamp;
return correctedReceivedAge + residentTime;
}
bool CurlCacheEntry::parseResponseHeaders(ResourceResponse& response)
{
double fileTime;
time_t fileModificationDate;
if (getFileModificationTime(m_headerFilename, fileModificationDate)) {
fileTime = difftime(fileModificationDate, 0);
fileTime *= 1000.0;
} else
fileTime = currentTimeMS(); // GMT
if (response.cacheControlContainsNoCache() || response.cacheControlContainsNoStore())
return false;
double maxAge = 0;
bool maxAgeIsValid = false;
if (response.cacheControlContainsMustRevalidate())
maxAge = 0;
else {
maxAge = response.cacheControlMaxAge();
if (std::isnan(maxAge))
maxAge = 0;
else
maxAgeIsValid = true;
}
if (!response.hasCacheValidatorFields())
return false;
double lastModificationDate = 0;
double responseDate = 0;
double expirationDate = 0;
lastModificationDate = response.lastModified();
if (std::isnan(lastModificationDate))
lastModificationDate = 0;
responseDate = response.date();
if (std::isnan(responseDate))
responseDate = 0;
expirationDate = response.expires();
if (std::isnan(expirationDate))
expirationDate = 0;
if (maxAgeIsValid) {
// when both the cache entry and the response contain max-age, the lesser one takes priority
double expires = fileTime + maxAge * 1000;
if (m_expireDate == -1 || m_expireDate > expires)
m_expireDate = expires;
} else if (responseDate > 0 && expirationDate >= responseDate)
m_expireDate = fileTime + (expirationDate - responseDate);
// if there were no lifetime information
if (m_expireDate == -1) {
if (lastModificationDate > 0)
m_expireDate = fileTime + (fileTime - lastModificationDate) * 0.1;
else
m_expireDate = 0;
}
String etag = response.httpHeaderField("ETag");
if (!etag.isNull())
m_requestHeaders.set("If-None-Match", etag);
String lastModified = response.httpHeaderField("Last-Modified");
if (!lastModified.isNull())
m_requestHeaders.set("If-Modified-Since", lastModified);
if (etag.isNull() && lastModified.isNull())
return false;
m_headerInMemory = true;
return true;
}
