From e724672302fe0e44ed431888903223c200cf8f8f Mon Sep 17 00:00:00 2001
From: John Mark Bell <jmb@netsurf-browser.org>
Date: Wed, 8 Feb 2006 00:35:05 +0000
Subject: [project @ 2006-02-08 00:35:05 by jmb] Handle case where no cache
 expiry headers are sent; use (now - last_modified) / 10. This should reduce
 the frequency of cache entry validation.

svn path=/import/netsurf/; revision=2064
---
 content/content.c    |  1 +
 content/fetch.c      | 11 +++++++++++
 content/fetch.h      |  1 +
 content/fetchcache.c | 15 ++++++++++-----
 4 files changed, 23 insertions(+), 5 deletions(-)

diff --git a/content/content.c b/content/content.c
index 9b5d3c8f2..adf0cb6c8 100644
--- a/content/content.c
+++ b/content/content.c
@@ -328,6 +328,7 @@ struct content * content_create(const char *url)
 	c->cache_data->max_age = INVALID_AGE;
 	c->cache_data->no_cache = false;
 	c->cache_data->etag = 0;
+	c->cache_data->last_modified = 0;
 
 	c->prev = 0;
 	c->next = content_list;
diff --git a/content/fetch.c b/content/fetch.c
index 9f1b93652..bbe4d3402 100644
--- a/content/fetch.c
+++ b/content/fetch.c
@@ -285,6 +285,7 @@ struct fetch * fetch_start(char *url, char *referer,
 	fetch->cachedata.max_age = INVALID_AGE;
 	fetch->cachedata.no_cache = false;
 	fetch->cachedata.etag = 0;
+	fetch->cachedata.last_modified = 0;
 	fetch->last_modified = 0;
 	fetch->file_etag = 0;
 	fetch->queue_prev = 0;
@@ -868,6 +869,13 @@ size_t fetch_curl_header(char *data, size_t size, size_t nmemb,
 				f->cachedata.etag[i] == '\r' ||
 				f->cachedata.etag[i] == '\n'); --i)
 			f->cachedata.etag[i] = '\0';
+	} else if (14 < size && strncasecmp(data, "Last-Modified:", 14) == 0) {
+		/* extract Last-Modified header */
+		SKIP_ST(14);
+		if (i < (int) size) {
+			f->cachedata.last_modified =
+					curl_getdate(&data[i], NULL);
+		}
 	}
 
 	return size;
@@ -948,6 +956,9 @@ bool fetch_process_headers(struct fetch *f)
 			sprintf(f->cachedata.etag,
 					"\"%10d\"", (int)s.st_mtime);
 
+		/* don't set last modified time so as to ensure that local
+		 * files are revalidated at all times. */
+
 		/* If performed a conditional request and unmodified ... */
 		if (f->last_modified && f->file_etag &&
 				f->last_modified > s.st_mtime &&
diff --git a/content/fetch.h b/content/fetch.h
index b65e150ff..633a87131 100644
--- a/content/fetch.h
+++ b/content/fetch.h
@@ -43,6 +43,7 @@ struct cache_data {
 	int max_age;		/**< Max-age Cache-control parameter */
 	bool no_cache;		/**< no-cache Cache-control parameter */
 	char *etag;		/**< Etag: response header */
+	time_t last_modified;	/**< Last-Modified: response header */
 };
 
 extern bool fetch_active;
diff --git a/content/fetchcache.c b/content/fetchcache.c
index 6e3f359f0..62fa07e3f 100644
--- a/content/fetchcache.c
+++ b/content/fetchcache.c
@@ -111,7 +111,9 @@ struct content * fetchcache(const char *url,
 			freshness_lifetime =
 				(cd->max_age != INVALID_AGE) ? cd->max_age :
 				(cd->expires != 0) ? cd->expires - cd->date :
-				0;
+				(cd->last_modified != 0) ?
+					(time(0) - cd->last_modified) / 10 :
+					0;
 
 			if (freshness_lifetime > current_age ||
 					cd->date == 0) {
@@ -127,10 +129,10 @@ struct content * fetchcache(const char *url,
 
 			/* Ok. We have a cache entry, but it appears stale.
 			 * Therefore, validate it. */
-			/** \todo perhaps it'd be better to use the
-			 * contents of the Last-Modified header here
-			 * instead */
-			date = c->cache_data->date;
+			if (cd->last_modified)
+				date = cd->last_modified;
+			else
+				date = c->cache_data->date;
 			etag = c->cache_data->etag;
 		}
 	}
@@ -585,6 +587,9 @@ void fetchcache_cache_update(struct content *c,
 		talloc_free(c->cache_data->etag);
 		c->cache_data->etag = talloc_strdup(c, data->etag);
 	}
+
+	if (data->last_modified)
+		c->cache_data->last_modified = data->last_modified;
 }
 
 
-- 
cgit v1.2.3