Improve doxygen comments and add todo for cache and backing store
This commit is contained in:
Vincent Sanders
parent
246a1fec05
commit
01b2bc5a57
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@ -16,8 +16,9 @@
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* along with this program. If not, see <http://www.gnu.org/licenses/>.
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*/
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/** \file
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* Low-level source data cache backing store interface
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/**
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* \file
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* Low-level source data cache backing store interface.
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*/
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#ifndef NETSURF_CONTENT_LLCACHE_PRIVATE_H_
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@ -33,7 +34,8 @@ enum backing_store_flags {
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BACKING_STORE_META = 1,
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};
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/** low level cache backing store operation table
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/**
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* low level cache backing store operation table
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*
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* The low level cache (source objects) has the capability to make
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* objects and their metadata (headers etc) persistant by writing to a
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@ -60,10 +62,12 @@ struct gui_llcache_table {
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*
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* The object is placed in the persistent store and may be
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* retrieved with the fetch method.
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*
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* The backing store will take a reference to the
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* passed data, subsequently the caller should explicitly
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* release the allocation using the release method and not
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* free the data itself.
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*
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* The caller may not assume that the persistent storage has
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* been completely written on return.
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*
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@ -83,6 +87,7 @@ struct gui_llcache_table {
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* length in \a datalen. Alternatively the backing store will
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* allocate its own buffer if \a data is NULL, this memory is
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* managed by the backing store.
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*
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* The caller must assume nothing about the backing store
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* allocated buffers and the storage and *must* be freed by
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* calling the release method.
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@ -25,6 +25,12 @@
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* \todo Consider improving eviction sorting to include objects size
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* and remaining lifetime and other cost metrics.
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*
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* \todo Implement mmap retrieval where supported.
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*
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* \todo Implement static retrival for metadata objects as their heap
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* lifetime is typically very short, though this may be obsoleted
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* by a small object storage stratagy.
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*
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* \todo make backing store have a more efficient small object storage.
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*
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*/
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@ -27,10 +27,12 @@
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*
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* \todo fix writeout conditions and ordering.
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*
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* \todo support mmaped retrieve
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*
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* \todo instrument and (auto)tune
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*
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* \todo Improve writeout bandwidth limiting.
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*
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* \todo Implement minimum writeout bandwidth limit.
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*
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*/
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#include <stdlib.h>
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@ -65,7 +67,9 @@
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#define LLCACHE_MIN_DISC_LIFETIME 3600
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#define LLCACHE_MAX_DISC_BANDWIDTH (512*1024)
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/** State of a low-level cache object fetch */
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/**
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* State of a low-level cache object fetch.
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*/
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typedef enum {
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LLCACHE_FETCH_INIT, /**< Initial state, before fetch */
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LLCACHE_FETCH_HEADERS, /**< Fetching headers */
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@ -73,10 +77,14 @@ typedef enum {
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LLCACHE_FETCH_COMPLETE /**< Fetch completed */
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} llcache_fetch_state;
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/** Type of low-level cache object */
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/**
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* Type of low-level cache object.
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*/
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typedef struct llcache_object llcache_object;
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/** Handle to low-level cache object */
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/**
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* Handle to low-level cache object.
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*/
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struct llcache_handle {
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llcache_object *object; /**< Pointer to associated object */
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@ -87,7 +95,9 @@ struct llcache_handle {
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size_t bytes; /**< Last reported byte count */
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};
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/** Low-level cache object user record */
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/**
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* Low-level cache object user record.
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*/
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typedef struct llcache_object_user {
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llcache_handle *handle; /**< Handle data for client */
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@ -98,7 +108,9 @@ typedef struct llcache_object_user {
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struct llcache_object_user *next; /**< Next in list */
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} llcache_object_user;
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/** Low-level cache object fetch context */
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/**
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* Low-level cache object fetch context.
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*/
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typedef struct {
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uint32_t flags; /**< Fetch flags */
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nsurl *referer; /**< Referring URL, or NULL if none */
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@ -117,14 +129,18 @@ typedef struct {
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bool outstanding_query; /**< Waiting for a query response */
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} llcache_fetch_ctx;
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/** validation control */
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/**
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* Validation control.
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*/
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typedef enum {
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LLCACHE_VALIDATE_FRESH, /**< Only revalidate if not fresh */
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LLCACHE_VALIDATE_ALWAYS, /**< Always revalidate */
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LLCACHE_VALIDATE_ONCE /**< Revalidate once only */
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} llcache_validate;
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/** cache control value for invalid age */
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/**
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* cache control value for invalid age.
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*/
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#define INVALID_AGE -1
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/** Cache control data */
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@ -153,8 +169,11 @@ typedef enum {
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LLCACHE_STATE_DISC, /**< source data is stored on disc */
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} llcache_store_state;
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/** Low-level cache object */
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/** \todo Consider whether a list is a sane container */
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/**
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* Low-level cache object
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*
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* \todo Consider whether a list is a sane container.
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*/
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struct llcache_object {
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llcache_object *prev; /**< Previous in list */
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llcache_object *next; /**< Next in list */
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@ -191,6 +210,9 @@ struct llcache_object {
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time_t last_used; /**< time the last user was removed from the object */
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};
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/**
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* Core llcache control context.
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*/
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struct llcache_s {
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/** Handler for fetch-related queries */
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llcache_query_callback query_cb;
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@ -235,9 +257,9 @@ static void llcache_users_not_caught_up(void);
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/**
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* Create a new object user
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*
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* \param cb Callback routine
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* \param pw Private data for callback
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* \param user Pointer to location to receive result
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* \param cb Callback routine
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* \param pw Private data for callback
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* \param user Pointer to location to receive result
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* \return NSERROR_OK on success, appropriate error otherwise
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*/
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static nserror llcache_object_user_new(llcache_handle_callback cb, void *pw,
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@ -616,7 +638,11 @@ static nserror llcache_fetch_parse_header(llcache_object *object,
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return NSERROR_OK;
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}
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/* Destroy headers */
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/**
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* Destroy headers.
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*
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* \param object The object to destroy headers within.
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*/
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static inline void llcache_destroy_headers(llcache_object *object)
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{
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while (object->num_headers > 0) {
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@ -629,7 +655,11 @@ static inline void llcache_destroy_headers(llcache_object *object)
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object->headers = NULL;
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}
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/* Invalidate cache control data */
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/**
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* Invalidate cache control data.
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*
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* \param object The object to invalidate cache control for.
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*/
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static inline void llcache_invalidate_cache_control_data(llcache_object *object)
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{
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free(object->cache.etag);
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@ -654,12 +684,13 @@ static nserror llcache_fetch_process_header(llcache_object *object,
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char *name, *value;
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llcache_header *temp;
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/* The headers for multiple HTTP responses may be delivered to us if
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* the fetch layer receives a 401 response for which it has
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* authentication credentials. This will result in a silent re-request
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* after which we'll receive the actual response headers for the
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* object we want to fetch (assuming that the credentials were correct
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* of course)
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/**
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* \note The headers for multiple HTTP responses may be
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* delivered to us if the fetch layer receives a 401 response
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* for which it has authentication credentials. This will
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* result in a silent re-request after which we'll receive the
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* actual response headers for the object we want to fetch
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* (assuming that the credentials were correct of course)
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*
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* Therefore, if the header is an HTTP response start marker, then we
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* must discard any headers we've read so far, reset the cache data
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@ -711,10 +742,10 @@ static nserror llcache_fetch_process_header(llcache_object *object,
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/**
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* (Re)fetch an object
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*
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* \pre The fetch parameters in object->fetch must be populated
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*
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* \param object Object to refetch
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* \return NSERROR_OK on success, appropriate error otherwise
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*
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* \pre The fetch parameters in object->fetch must be populated
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*/
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static nserror llcache_object_refetch(llcache_object *object)
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{
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@ -724,10 +755,11 @@ static nserror llcache_object_refetch(llcache_object *object)
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int header_idx = 0;
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if (object->fetch.post != NULL) {
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if (object->fetch.post->type == LLCACHE_POST_URL_ENCODED)
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if (object->fetch.post->type == LLCACHE_POST_URL_ENCODED) {
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urlenc = object->fetch.post->data.urlenc;
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else
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} else {
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multipart = object->fetch.post->data.multipart;
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}
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}
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/* Generate cache-control headers */
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@ -750,6 +782,7 @@ static nserror llcache_object_refetch(llcache_object *object)
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header_idx++;
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}
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if (object->cache.date != 0) {
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/* Maximum length of an RFC 1123 date is 29 bytes */
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const size_t len = SLEN("If-Modified-Since: ") + 29 + 1;
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@ -803,17 +836,17 @@ static nserror llcache_object_refetch(llcache_object *object)
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/**
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* Kick-off a fetch for an object
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*
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* \pre object::url must contain the URL to fetch
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* \pre If there is a freshness validation candidate,
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* object::candidate and object::cache must be filled in
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* \pre There must not be a fetch in progress for \a object
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*
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* \param object Object to fetch
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* \param flags Fetch flags
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* \param referer Referring URL, or NULL for none
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* \param post POST data, or NULL for GET
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* \param redirect_count Number of redirects followed so far
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* \return NSERROR_OK on success, appropriate error otherwise
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*
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* \pre object::url must contain the URL to fetch
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* \pre If there is a freshness validation candidate,
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* object::candidate and object::cache must be filled in
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* \pre There must not be a fetch in progress for \a object
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*/
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static nserror llcache_object_fetch(llcache_object *object, uint32_t flags,
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nsurl *referer, const llcache_post_data *post,
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@ -845,12 +878,12 @@ static nserror llcache_object_fetch(llcache_object *object, uint32_t flags,
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/**
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* Destroy a low-level cache object
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*
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* \param object Object to destroy
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* \return NSERROR_OK on success, appropriate error otherwise
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*
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* \pre Object is detached from cache list
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* \pre Object has no users
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* \pre Object is not a candidate (i.e. object::candidate_count == 0)
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*
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* \param object Object to destroy
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* \return NSERROR_OK on success, appropriate error otherwise
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*/
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static nserror llcache_object_destroy(llcache_object *object)
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{
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@ -987,12 +1020,12 @@ static bool llcache_object_is_fresh(const llcache_object *object)
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/**
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* Clone an object's cache data
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*
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* \post If \a deep is false, then any pointers in \a source will be set to NULL
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*
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* \param source Source object containing cache data to clone
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* \param destination Destination object to clone cache data into
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* \param deep Whether to deep-copy the data or not
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* \return NSERROR_OK on success, appropriate error otherwise
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*
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* \post If \a deep is false, then any pointers in \a source will be set to NULL
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*/
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static nserror llcache_object_clone_cache_data(llcache_object *source,
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llcache_object *destination, bool deep)
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@ -1067,11 +1100,11 @@ llcache_object_remove_from_list(llcache_object *object, llcache_object **list)
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* Retrieve source data for an object from persistant store if necessary.
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*
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* If an objects source data has been placed in the persistant store
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* and the in memory copy freed this will attempt to retrive the
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* and the in memory copy released this will attempt to retrive the
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* source data.
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*
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* @param object the object to operate on.
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* @return apropriate error code.
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* \param object the object to operate on.
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* \return apropriate error code.
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*/
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static nserror llcache_persist_retrieve(llcache_object *object)
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{
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@ -1094,7 +1127,15 @@ static nserror llcache_persist_retrieve(llcache_object *object)
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/**
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* Generate a serialised version of an objects metadata
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*
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* metadata includes object headers
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* The metadata includes object headers.
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*
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* \param object The cache object to serialise teh metadata of.
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* \param data_out Where the serialised buffer will be placed.
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* \param datasize_out The size of the serialised data.
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* \return NSERROR_OK on success with \a data_out and \a datasize_out
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* updated, NSERROR_NOMEM on memory exhaustion or
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* NSERROR_INVALID if there was an error serialising the
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* stream.
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*/
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static nserror
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llcache_serialise_metadata(llcache_object *object,
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@ -1228,7 +1269,15 @@ operror:
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}
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/**
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* un-serialise an objects metadata.
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* Deserialisation of an objects metadata.
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*
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* Attempt to retrive and deserialise the metadata for an object from
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* the backing store.
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*
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* \param object The object to retrieve the metadata for.
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* \return NSERROR_OK if the metatdata was retrived and deserialised
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* or error code if url is not in persistant storage or in
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* event of deserialisation error.
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*/
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static nserror
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llcache_process_metadata(llcache_object *object)
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@ -1366,7 +1415,15 @@ format_error:
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}
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/**
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* attempt to retrieve an object from persistant storage.
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* Attempt to retrieve an object from persistant storage.
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*
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* \param object The object to populate from persistant store.
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* \param flags Fetch flags.
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* \param referer The referring url.
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* \param post Post data for fetch.
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* \param redirect_count how many times this fetch has been redirected.
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* \return NSERROR_OK if the object was sucessfully retrived from the
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* cache else appropriate error code.
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*/
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static nserror
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llcache_object_fetch_persistant(llcache_object *object,
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@ -1674,11 +1731,12 @@ static nserror llcache_object_retrieve(nsurl *url, uint32_t flags,
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return NSERROR_OK;
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}
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/**
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* Add a user to a low-level cache object
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*
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* \param object Object to add user to
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* \param user User to add
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* \param object Object to add user to
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* \param user User to add
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* \return NSERROR_OK.
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*/
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static nserror llcache_object_add_user(llcache_object *object,
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@ -1924,7 +1982,9 @@ llcache_fetch_process_data(llcache_object *object,
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size_t len)
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{
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if (object->fetch.state != LLCACHE_FETCH_DATA) {
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/* On entry into this state, check if we need to
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/**
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* \note
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* On entry into this state, check if we need to
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* invalidate the cache control data. We are guaranteed
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* to have received all response headers.
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*
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@ -2162,7 +2222,7 @@ static nserror llcache_fetch_ssl_error(llcache_object *object)
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}
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/**
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* construct a sorted list of objects available for writeout operation
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* Construct a sorted list of objects available for writeout operation.
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*
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* The list contains fresh cacheable objects held in RAM with no
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* pending fetches. Any objects with a remaining lifetime less than
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@ -2171,6 +2231,10 @@ static nserror llcache_fetch_ssl_error(llcache_object *object)
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*
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* \todo calculate useful cost metrics to improve sorting.
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*
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* \param[out] lst_out list of candidate objects.
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* \param[out] lst_len_out Number of candidate objects in result.
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* \return NSERROR_OK with \a lst_out and \a lst_len_out updated or
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* error code.
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*/
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static nserror
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build_candidate_list(struct llcache_object ***lst_out, int *lst_len_out)
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@ -2222,6 +2286,13 @@ build_candidate_list(struct llcache_object ***lst_out, int *lst_len_out)
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return NSERROR_OK;
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}
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/**
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* Write an object to the backing store.
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*
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* \param object The object to put in the backing store.
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* \param written_out The amount of data written out.
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* \return NSERROR_OK on success or appropriate error code.
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*/
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static nserror
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write_backing_store(struct llcache_object *object, size_t *written_out)
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{
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@ -2268,7 +2339,9 @@ write_backing_store(struct llcache_object *object, size_t *written_out)
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}
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/**
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* possibly write objects data to backing store.
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* Possibly write objects data to backing store.
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*
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* \param p The context pointer passed to the callback.
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*/
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static void llcache_persist(void *p)
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{
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@ -2308,8 +2381,8 @@ static void llcache_persist(void *p)
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/**
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* Handler for fetch events
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*
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||||
* \param msg Fetch event
|
||||
* \param p Our private data
|
||||
* \param msg Fetch event
|
||||
* \param p Our private data
|
||||
*/
|
||||
static void llcache_fetch_callback(const fetch_msg *msg, void *p)
|
||||
{
|
||||
|
|
@ -2810,6 +2883,9 @@ llcache_object_snapshot(llcache_object *object, llcache_object **snapshot)
|
|||
|
||||
/**
|
||||
* total ram usage of object
|
||||
*
|
||||
* \param object The object to caclulate the total RAM usage of.
|
||||
* \return The total RAM usage in bytes.
|
||||
*/
|
||||
static inline uint32_t
|
||||
total_object_size(llcache_object *object)
|
||||
|
|
@ -3012,7 +3088,7 @@ void llcache_clean(bool purge)
|
|||
LLCACHE_LOG(("Size: %u", llcache_size));
|
||||
}
|
||||
|
||||
/* See llcache.h for documentation */
|
||||
/* Exported interface documented in content/llcache.h */
|
||||
nserror
|
||||
llcache_initialise(const struct llcache_parameters *prm)
|
||||
{
|
||||
|
|
@ -3034,7 +3110,8 @@ llcache_initialise(const struct llcache_parameters *prm)
|
|||
return guit->llcache->initialise(&prm->store);
|
||||
}
|
||||
|
||||
/* See llcache.h for documentation */
|
||||
|
||||
/* Exported interface documented in content/llcache.h */
|
||||
void llcache_finalise(void)
|
||||
{
|
||||
llcache_object *object, *next;
|
||||
|
|
@ -3119,7 +3196,7 @@ static void llcache_catch_up_all_users(void *ignored)
|
|||
* Ask for ::llcache_catch_up_all_users to be scheduled ASAP to pump the
|
||||
* user state machines.
|
||||
*/
|
||||
static void llcache_users_not_caught_up()
|
||||
static void llcache_users_not_caught_up(void)
|
||||
{
|
||||
if (llcache->all_caught_up) {
|
||||
llcache->all_caught_up = false;
|
||||
|
|
@ -3128,7 +3205,7 @@ static void llcache_users_not_caught_up()
|
|||
}
|
||||
|
||||
|
||||
/* See llcache.h for documentation */
|
||||
/* Exported interface documented in content/llcache.h */
|
||||
nserror llcache_handle_retrieve(nsurl *url, uint32_t flags,
|
||||
nsurl *referer, const llcache_post_data *post,
|
||||
llcache_handle_callback cb, void *pw,
|
||||
|
|
@ -3166,7 +3243,8 @@ nserror llcache_handle_retrieve(nsurl *url, uint32_t flags,
|
|||
return NSERROR_OK;
|
||||
}
|
||||
|
||||
/* See llcache.h for documentation */
|
||||
|
||||
/* Exported interface documented in content/llcache.h */
|
||||
nserror llcache_handle_change_callback(llcache_handle *handle,
|
||||
llcache_handle_callback cb, void *pw)
|
||||
{
|
||||
|
|
@ -3176,7 +3254,8 @@ nserror llcache_handle_change_callback(llcache_handle *handle,
|
|||
return NSERROR_OK;
|
||||
}
|
||||
|
||||
/* See llcache.h for documentation */
|
||||
|
||||
/* Exported interface documented in content/llcache.h */
|
||||
nserror llcache_handle_release(llcache_handle *handle)
|
||||
{
|
||||
nserror error = NSERROR_OK;
|
||||
|
|
@ -3200,7 +3279,7 @@ nserror llcache_handle_release(llcache_handle *handle)
|
|||
return error;
|
||||
}
|
||||
|
||||
/* See llcache.h for documentation */
|
||||
/* Exported interface documented in content/llcache.h */
|
||||
nserror llcache_handle_clone(llcache_handle *handle, llcache_handle **result)
|
||||
{
|
||||
nserror error;
|
||||
|
|
|
|||
Loading…
Reference in New Issue