1 file changed, 14 insertions, 24 deletions

diff --git a/source/cache.c b/source/cache.cindex dd8ae7f..2d546bb 100644--- a/source/cache.c+++ b/source/cache.c@@ -96,9 +96,8 @@ static int open_slot(struct cache_slot *slot) }  /*- * A key longer than the buffer above can never be read back by open_slot, so- * a slot keyed on one would never match and every such request would- * regenerate its page while still writing a slot nothing can use.+ * A key longer than the buffer above can never be read back by open_slot,+ * so a slot keyed on one would be written but never match.  */ static int key_fits_slot(const char *key) {@@ -238,10 +237,8 @@ static int lock_slot(struct cache_slot *slot) 	} 	// The lock landed on whatever inode the path named at open. A holder 	// finishing in between renames that inode into place as the live-	// slot, so truncating it on the strength of the stale descriptor-	// would tear down the page other requests are reading. Once the path-	// is confirmed to still name this file the rename can no longer-	// happen, because doing so takes the lock now held here.+	// slot, and once the path is confirmed to still name this file that+	// rename can no longer happen, because it takes the lock held here. 	if (fstat(slot->lock_fd, &held) || stat(slot->lock_path, &named) || 	    held.st_ino != named.st_ino || held.st_dev != named.st_dev) { 		close(slot->lock_fd);@@ -291,10 +288,9 @@ void cache_abandon_fill(void) 	slot_being_filled = NULL; 	slot->abandoned = 1; -	// The page is sitting in html.c's buffer and in stdio's, and both are-	// emptied while stdout still points at the lock file, so the half-	// rendered page goes into the file about to be removed rather than-	// reaching the client ahead of whatever is written next.+	// The page is sitting in html.c's buffer and in stdio's. Empty both+	// while stdout still points at the lock file so the half rendered+	// page never reaches the client. 	html_flush(); 	fflush(stdout); @@ -323,10 +319,9 @@ static int fill_slot(struct cache_slot *slot) 	slot->fn(); 	slot_being_filled = NULL; -	// The page is sitting in html.c's buffer and then in stdio's, and all-	// of it has to reach the lock file before that file is renamed into-	// place. After an abandoned fill stdout is the client again and this-	// same flush delivers the tail of the error page instead.+	// All of the page has to reach the lock file before it is renamed+	// into place. After an abandoned fill stdout is the client again and+	// this same flush delivers the tail of the error page instead. 	html_flush(); 	if (fflush(stdout)) 		return errno;@@ -352,9 +347,7 @@ static void refresh_slot(struct cache_slot *slot) 		return;  	// If another process replaced the slot between open_slot and-	// lock_slot, the copy already open is served rather than the newer-	// one, which would mean opening that file and comparing the key in it,-	// not worth a second descriptor and read on every expiry.+	// lock_slot, the copy already open is served rather than the newer. 	if (is_modified(slot) || fill_slot(slot)) { 		unlock_slot(slot, 0); 		close_lock(slot);@@ -391,8 +384,7 @@ static int process_slot(struct cache_slot *slot)  	// A slot that opened cleanly but holds another key is a collision, 	// and two popular pages sharing one slot evict each other on every-	// alternating visit. Nothing else makes that visible, because the-	// cache keeps working and only quietly stops helping.+	// alternating visit. 	if (!err) 		log_error("[cgit] Cache slot %s holds a different key, " 			  "consider a larger cache-size\n", slot->path);@@ -449,10 +441,8 @@ static char *format_time(const char *format, time_t when) }  /*- * The accumulator is an unsigned long rather than a fixed 32 bit type, so on a- * 64 bit host this is not the published FNV-1 value. All that decides is which- * slot a key lands in, and nothing outside a single build has to agree on the- * answer.+ * The accumulator is unsigned long, so on a 64 bit host this is not the+ * published FNV-1 value. Only slot selection depends on it.  */ unsigned long cache_hash_str(const char *str) {
diff --git a/source/cache.c b/source/cache.c
index dd8ae7f..2d546bb 100644
--- a/source/cache.c
+++ b/source/cache.c
@@ -96,9 +96,8 @@ static int open_slot(struct cache_slot *slot)
 }
 
 /*
- * A key longer than the buffer above can never be read back by open_slot, so
- * a slot keyed on one would never match and every such request would
- * regenerate its page while still writing a slot nothing can use.
+ * A key longer than the buffer above can never be read back by open_slot,
+ * so a slot keyed on one would be written but never match.
  */
 static int key_fits_slot(const char *key)
 {
@@ -238,10 +237,8 @@ static int lock_slot(struct cache_slot *slot)
 	}
 	// The lock landed on whatever inode the path named at open. A holder
 	// finishing in between renames that inode into place as the live
-	// slot, so truncating it on the strength of the stale descriptor
-	// would tear down the page other requests are reading. Once the path
-	// is confirmed to still name this file the rename can no longer
-	// happen, because doing so takes the lock now held here.
+	// slot, and once the path is confirmed to still name this file that
+	// rename can no longer happen, because it takes the lock held here.
 	if (fstat(slot->lock_fd, &held) || stat(slot->lock_path, &named) ||
 	    held.st_ino != named.st_ino || held.st_dev != named.st_dev) {
 		close(slot->lock_fd);
@@ -291,10 +288,9 @@ void cache_abandon_fill(void)
 	slot_being_filled = NULL;
 	slot->abandoned = 1;
 
-	// The page is sitting in html.c's buffer and in stdio's, and both are
-	// emptied while stdout still points at the lock file, so the half
-	// rendered page goes into the file about to be removed rather than
-	// reaching the client ahead of whatever is written next.
+	// The page is sitting in html.c's buffer and in stdio's. Empty both
+	// while stdout still points at the lock file so the half rendered
+	// page never reaches the client.
 	html_flush();
 	fflush(stdout);
 
@@ -323,10 +319,9 @@ static int fill_slot(struct cache_slot *slot)
 	slot->fn();
 	slot_being_filled = NULL;
 
-	// The page is sitting in html.c's buffer and then in stdio's, and all
-	// of it has to reach the lock file before that file is renamed into
-	// place. After an abandoned fill stdout is the client again and this
-	// same flush delivers the tail of the error page instead.
+	// All of the page has to reach the lock file before it is renamed
+	// into place. After an abandoned fill stdout is the client again and
+	// this same flush delivers the tail of the error page instead.
 	html_flush();
 	if (fflush(stdout))
 		return errno;
@@ -352,9 +347,7 @@ static void refresh_slot(struct cache_slot *slot)
 		return;
 
 	// If another process replaced the slot between open_slot and
-	// lock_slot, the copy already open is served rather than the newer
-	// one, which would mean opening that file and comparing the key in it,
-	// not worth a second descriptor and read on every expiry.
+	// lock_slot, the copy already open is served rather than the newer.
 	if (is_modified(slot) || fill_slot(slot)) {
 		unlock_slot(slot, 0);
 		close_lock(slot);
@@ -391,8 +384,7 @@ static int process_slot(struct cache_slot *slot)
 
 	// A slot that opened cleanly but holds another key is a collision,
 	// and two popular pages sharing one slot evict each other on every
-	// alternating visit. Nothing else makes that visible, because the
-	// cache keeps working and only quietly stops helping.
+	// alternating visit.
 	if (!err)
 		log_error("[cgit] Cache slot %s holds a different key, "
 			  "consider a larger cache-size\n", slot->path);
@@ -449,10 +441,8 @@ static char *format_time(const char *format, time_t when)
 }
 
 /*
- * The accumulator is an unsigned long rather than a fixed 32 bit type, so on a
- * 64 bit host this is not the published FNV-1 value. All that decides is which
- * slot a key lands in, and nothing outside a single build has to agree on the
- * answer.
+ * The accumulator is unsigned long, so on a 64 bit host this is not the
+ * published FNV-1 value. Only slot selection depends on it.
  */
 unsigned long cache_hash_str(const char *str)
 {