the nsIRequest:: load flags need to be revised. the issues are: 1) need to support caching "no-cache" content for session history 2) VALIDATE_ALWAYS is unnecessary/redundant. it can be replaced by either FORCE_VALIDATION or LOAD_NORMAL, depending on your interpretation of this flag ;-) we can resolve these issues by adding the following flags: STORE_NO_CACHE_CONTENT - allow caching of content that should not be reused REUSE_NO_CACHE_CONTENT - allow reuse of content that shouldn't be reused and removing VALIDATE_ALWAYS as it is currently equivalent to LOAD_NORMAL.

gordon and i have developed a much simpler and (hopefully) more intuitive set of load flags: MUST_RELOAD - must ignore cached content and reload MUST_VALIDATE - must validate cached content DONT_VALIDATE - use whatever is in the cache DONT_VALIDATE_EXPIRED - dont validate things that have expired, but always reload/validate no-cache content. DONT_VALIDATE_EXPIRED_IF_RECENT - dont validate things that have expired if they were created/already-validated this session, but always reload/validate no-cache content. the last two flags correspond to the browsing modes "validate never" and "validate once per session." if none of the flags are set, then validation will be automatic, meaning only if the content has expired or if the content must be validated. as a comment: it turns out that http permits caching of all downloaded content; however, some content simply must be validated before it can be reused. this is why the last two flags listed above do not rule out validation in all cases. this means that the STORE_NO_CACHE_CONTENT flag that i previously proposed is unnecessary.

i've been studying the way ns4x and ie5 interpret the cache validation flags, and i believe that the way i've interpreted them is consistent. i feel that this is very important for maintaining expected browser behavior w.r.t. caching and validation.

Discussed this extensively with gordon and gagan on friday, and we settled on a hopefully simpler set of load flags: LOAD_NORMAL - normal browsing LOAD_BYPASS_CACHE - ignore cached response, replaces FORCE_RELOAD LOAD_FROM_CACHE - trust cached response, even if the cached response was not meant to be reused without validation. if LOAD_NORMAL, then the following flags also apply: VALIDATE_ALWAYS - validate *all* cached responses before reusing. VALIDATE_ONCE_PER_SESSION - always validate cached responses that were not meant to be reused. don't bother validating other cached responses if already validated this session. VALIDATE_NEVER - always validate cached responses that were not meant to be reused. don't bother validating other cached responses. if LOAD_NORMAL and none of the VALIDATE_ bits are set, then validation is performed automatically (based on expiration times, etc).

A patch for the flags as just described was checked in on friday 4/13.

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