refactor llcache header processing
refactor the header processing in the low level object cache to make cache control header processing more explicit.
This commit is contained in:
Vincent Sanders
parent
0601b7dbec
commit
92424b6946
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@ -481,6 +481,14 @@ static nserror llcache_post_data_clone(const llcache_post_data *orig,
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/**
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* Split a fetch header into name and value
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*
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* HTTP header splitting according to grammar defined in RFC7230 section 3.2
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* https://tools.ietf.org/html/rfc7230#section-3.2
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*
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* This implementation is non conformant in that it:
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* - includes carrige return and newline in whitespace (3.2.3)
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* - allows whitespace before and after the field-name token (3.2.4)
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* - does not handle obsolete line folding (3.2.4)
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*
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* \param data Header string
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* \param len Byte length of header
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* \param name Pointer to location to receive header name
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@ -566,127 +574,146 @@ static nserror llcache_fetch_split_header(const uint8_t *data, size_t len,
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}
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/**
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* Parse a fetch header
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* parse cache control header value
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*
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* \param object Object to parse header for
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* \param data Header string
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* \param len Byte length of header
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* \param name Pointer to location to receive header name
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* \param value Pointer to location to receive header value
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* \param object Object to parse header for
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* \param value header value
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* \return NSERROR_OK on success, appropriate error otherwise
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*
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* \note This function also has the side-effect of updating
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* the cache control data for the object if an interesting
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* header is encountered
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*/
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static nserror llcache_fetch_parse_header(llcache_object *object,
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const uint8_t *data, size_t len, char **name, char **value)
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static nserror
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llcache_fetch_parse_cache_control(llcache_object *object, char *value)
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{
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nserror res;
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const char *start = value;
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const char *comma = value;
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/* Set fetch response time if not already set */
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if (object->cache.res_time == 0) {
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object->cache.res_time = time(NULL);
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}
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while (*comma != '\0') {
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while (*comma != '\0' && *comma != ',') {
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comma++;
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}
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/* Decompose header into name-value pair */
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res = llcache_fetch_split_header(data, len, name, value);
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if (res != NSERROR_OK) {
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return res;
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}
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/* Parse cache headers to populate cache control data */
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if ((5 < len) &&
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strcasecmp(*name, "Date") == 0) {
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/* extract Date header */
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nsc_strntimet(*value,
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strlen(*value),
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&object->cache.date);
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} else if ((4 < len) &&
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strcasecmp(*name, "Age") == 0) {
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/* extract Age header */
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if ('0' <= **value && **value <= '9') {
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object->cache.age = atoi(*value);
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}
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} else if ((8 < len) &&
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strcasecmp(*name, "Expires") == 0) {
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/* extract Expires header */
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res = nsc_strntimet(*value,
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strlen(*value),
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&object->cache.expires);
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if (res != NSERROR_OK) {
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object->cache.expires = (time_t)0x7fffffff;
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}
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} else if ((14 < len) &&
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strcasecmp(*name, "Cache-Control") == 0) {
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/* extract and parse Cache-Control header */
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const char *start = *value;
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const char *comma = *value;
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while (*comma != '\0') {
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while (*comma != '\0' && *comma != ',') {
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comma++;
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}
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if ((8 < comma - start) &&
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(strncasecmp(start, "no-cache", 8) == 0 ||
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strncasecmp(start, "no-store", 8) == 0)) {
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/**
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* \todo When we get a disk cache we should
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* distinguish between these two.
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*/
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object->cache.no_cache = LLCACHE_VALIDATE_ALWAYS;
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} else if ((7 < comma - start) &&
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strncasecmp(start, "max-age", 7) == 0) {
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/* Find '=' */
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while (start < comma && *start != '=') {
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start++;
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}
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/* Skip over it */
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if ((8 < comma - start) &&
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(strncasecmp(start, "no-cache", 8) == 0 ||
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strncasecmp(start, "no-store", 8) == 0)) {
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/**
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* \todo When we get a disk cache we should
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* distinguish between these two.
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*/
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object->cache.no_cache = LLCACHE_VALIDATE_ALWAYS;
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} else if ((7 < comma - start) &&
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strncasecmp(start, "max-age", 7) == 0) {
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/* Find '=' */
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while (start < comma && *start != '=') {
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start++;
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}
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/* Skip over it */
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start++;
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#define SKIP_ST(p) while (*p != '\0' && (*p == ' ' || *p == '\t')) p++
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/* Skip whitespace */
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SKIP_ST(start);
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/* Skip whitespace */
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SKIP_ST(start);
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if (start < comma) {
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object->cache.max_age = atoi(start);
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}
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if (start < comma) {
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object->cache.max_age = atoi(start);
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}
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}
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if (*comma != '\0') {
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/* Skip past comma */
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comma++;
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/* Skip whitespace */
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SKIP_ST(comma);
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}
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if (*comma != '\0') {
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/* Skip past comma */
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comma++;
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/* Skip whitespace */
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SKIP_ST(comma);
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}
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#undef SKIP_ST
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/* Set start for next token */
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start = comma;
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}
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} else if ((5 < len) &&
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(strcasecmp(*name, "ETag") == 0)) {
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/* extract ETag header */
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free(object->cache.etag);
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object->cache.etag = strdup(*value);
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if (object->cache.etag == NULL) {
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free(*name);
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free(*value);
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return NSERROR_NOMEM;
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}
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} else if ((14 < len) &&
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(strcasecmp(*name, "Last-Modified") == 0)) {
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/* extract Last-Modified header */
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nsc_strntimet(*value,
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strlen(*value),
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&object->cache.last_modified);
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/* Set start for next token */
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start = comma;
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}
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return NSERROR_OK;
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}
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/**
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* Update cache control from appropriate header
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*
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* \param object Object to parse header for
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* \param name header name
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* \param value header value
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* \return NSERROR_OK on success, appropriate error otherwise
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*/
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static nserror
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llcache_fetch_header_cache_control(llcache_object *object,
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char *name,
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char *value)
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{
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nserror res;
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size_t name_len;
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/* Parse cache headers to populate cache control data */
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name_len = strlen(name);
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switch (name_len) {
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case 3:
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if (strcasecmp(name, "Age") == 0) {
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/* extract Age header */
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if ('0' <= *value && *value <= '9') {
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object->cache.age = atoi(value);
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}
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}
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break;
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case 4:
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if (strcasecmp(name, "Date") == 0) {
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/* extract Date header */
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res = nsc_strntimet(value,
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strlen(value),
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&object->cache.date);
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if (res != NSERROR_OK) {
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NSLOG(llcache, INFO,
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"Processing Date header value \"%s\" returned %d",
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value, res);
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}
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} else if (strcasecmp(name, "ETag") == 0) {
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/* extract ETag header */
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free(object->cache.etag);
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object->cache.etag = strdup(value);
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if (object->cache.etag == NULL) {
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NSLOG(llcache, INFO,
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"No memory to duplicate ETag");
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return NSERROR_NOMEM;
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}
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}
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break;
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case 7:
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if (strcasecmp(name, "Expires") == 0) {
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/* process Expires header value */
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res = nsc_strntimet(value,
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strlen(value),
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&object->cache.expires);
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if (res != NSERROR_OK) {
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NSLOG(llcache, INFO,
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"Processing Expires header value \"%s\" returned %d",
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value, res);
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object->cache.expires = (time_t)0x7fffffff;
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}
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}
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break;
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case 13:
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if (strcasecmp(name, "Cache-Control") == 0) {
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/* parse Cache-Control header value */
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llcache_fetch_parse_cache_control(object,value);
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} else if (strcasecmp(name, "Last-Modified") == 0) {
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/* parse Last-Modified header value */
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nsc_strntimet(value,
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strlen(value),
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&object->cache.last_modified);
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}
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break;
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}
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return NSERROR_OK;
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}
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@ -733,7 +760,7 @@ static inline void llcache_invalidate_cache_control_data(llcache_object *object)
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static nserror llcache_fetch_process_header(llcache_object *object,
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const uint8_t *data, size_t len)
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{
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nserror error;
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nserror res;
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char *name, *value;
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llcache_header *temp;
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@ -761,9 +788,15 @@ static nserror llcache_fetch_process_header(llcache_object *object,
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llcache_destroy_headers(object);
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}
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error = llcache_fetch_parse_header(object, data, len, &name, &value);
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if (error != NSERROR_OK) {
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return error;
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/* Set fetch response time if not already set */
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if (object->cache.res_time == 0) {
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object->cache.res_time = time(NULL);
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}
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/* Parse header into name-value pair */
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res = llcache_fetch_split_header(data, len, &name, &value);
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if (res != NSERROR_OK) {
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return res;
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}
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/* deal with empty header */
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@ -773,9 +806,17 @@ static nserror llcache_fetch_process_header(llcache_object *object,
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return NSERROR_OK;
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}
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/* update cache control data from header */
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res = llcache_fetch_header_cache_control(object, name, value);
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if (res != NSERROR_OK) {
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free(name);
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free(value);
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return res;
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}
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/* Append header data to the object's headers array */
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temp = realloc(object->headers, (object->num_headers + 1) *
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sizeof(llcache_header));
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temp = realloc(object->headers,
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(object->num_headers + 1) * sizeof(llcache_header));
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if (temp == NULL) {
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free(name);
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free(value);
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@ -1586,9 +1627,11 @@ llcache_object_retrieve_from_cache(nsurl *url,
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nserror error;
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llcache_object *obj, *newest = NULL;
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NSLOG(llcache, DEBUG, "Searching cache for %s flags:%x referer:%s post:%p",
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nsurl_access(url), flags,
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referer==NULL?"":nsurl_access(referer), post);
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NSLOG(llcache, DEBUG,
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"Searching cache for %s flags:%x referer:%s post:%p",
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nsurl_access(url), flags,
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referer==NULL?"":nsurl_access(referer),
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post);
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/* Search for the most recently fetched matching object */
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for (obj = llcache->cached_objects; obj != NULL; obj = obj->next) {
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@ -3784,9 +3827,10 @@ nserror llcache_handle_force_stream(llcache_handle *handle)
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/* See llcache.h for documentation */
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nserror llcache_handle_invalidate_cache_data(llcache_handle *handle)
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{
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if (handle->object != NULL && handle->object->fetch.fetch == NULL &&
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handle->object->cache.no_cache ==
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LLCACHE_VALIDATE_FRESH) {
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if ((handle->object != NULL) &&
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(handle->object->fetch.fetch == NULL) &&
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(handle->object->cache.no_cache == LLCACHE_VALIDATE_FRESH)) {
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/* mark the cached object as requiring validation */
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handle->object->cache.no_cache = LLCACHE_VALIDATE_ONCE;
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}
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