[multiple] static file optimization; reuse cache

reuse cache lookup in common case of serving a static file
rather than repeating the stat_cache_entry lookup
(which is more work than memcmp() to re-check stat_cache_entry match)

src/http-header-glue.c

@@ -305,16 +305,24 @@ handler_t http_response_reqbody_read_error (request_st * const r, int http_statu
 }
 
 
-void http_response_send_file (request_st * const r, buffer * const path) {
-	stat_cache_entry * const sce = stat_cache_get_entry_open(path, r->conf.follow_symlink);
-	const buffer *mtime = NULL;
-	int allow_caching = (0 == r->http_status || 200 == r->http_status);
-
-	if (NULL == sce) {
-		r->http_status = (errno == ENOENT) ? 404 : 403;
-		log_error(r->conf.errh, __FILE__, __LINE__,
-		  "not a regular file: %s -> %s", r->uri.path.ptr, path->ptr);
-		return;
+void http_response_send_file (request_st * const r, buffer * const path, stat_cache_entry *sce) {
+	if (NULL == sce
+	    || (sce->fd < 0 && 0 != sce->st.st_size)) {
+		sce = stat_cache_get_entry_open(path, r->conf.follow_symlink);
+		if (NULL == sce) {
+			r->http_status = (errno == ENOENT) ? 404 : 403;
+			log_error(r->conf.errh, __FILE__, __LINE__,
+			  "not a regular file: %s -> %s", r->uri.path.ptr, path->ptr);
+			return;
+		}
+		if (sce->fd < 0 && 0 != sce->st.st_size) {
+			r->http_status = (errno == ENOENT) ? 404 : 403;
+			if (r->conf.log_request_handling) {
+				log_perror(r->conf.errh, __FILE__, __LINE__,
+				  "file open failed: %s", path->ptr);
+			}
+			return;
+		}
 	}
 
 	if (!r->conf.follow_symlink
@@ -340,14 +348,7 @@ void http_response_send_file (request_st * const r, buffer * const path) {
 		return;
 	}
 
-	if (sce->fd < 0 && 0 != sce->st.st_size) {
-		r->http_status = (errno == ENOENT) ? 404 : 403;
-		if (r->conf.log_request_handling) {
-			log_perror(r->conf.errh, __FILE__, __LINE__,
-			  "file open failed: %s", path->ptr);
-		}
-		return;
-	}
+	int allow_caching = (0 == r->http_status || 200 == r->http_status);
 
 	/* set response content-type, if not set already */
 
@@ -386,6 +387,7 @@ void http_response_send_file (request_st * const r, buffer * const path) {
 		}
 
 		/* prepare header */
+		const buffer *mtime;
 		mtime = http_header_response_get(r, HTTP_HEADER_LAST_MODIFIED,
 		                                 CONST_STR_LEN("Last-Modified"));
 		if (NULL == mtime) {
@@ -484,7 +486,7 @@ static void http_response_xsendfile (request_st * const r, buffer * const path,
 		}
 	}
 
-	if (valid) http_response_send_file(r, path);
+	if (valid) http_response_send_file(r, path, NULL);
 
 	if (r->http_status >= 400 && status < 300) {
 		r->handler_module = NULL;

src/mod_cgi.c

@@ -747,7 +747,8 @@ URIHANDLER_FUNC(cgi_is_handled) {
 	data_string *ds;
 
 	if (NULL != r->handler_module) return HANDLER_GO_ON;
-	if (buffer_is_empty(&r->physical.path)) return HANDLER_GO_ON;
+	/* r->physical.path is non-empty for handle_subrequest_start */
+	/*if (buffer_string_is_empty(&r->physical.path)) return HANDLER_GO_ON;*/
 
 	mod_cgi_patch_config(r, p);
 	if (NULL == p->conf.cgi) return HANDLER_GO_ON;
@@ -755,7 +756,12 @@ URIHANDLER_FUNC(cgi_is_handled) {
 	ds = (data_string *)array_match_key_suffix(p->conf.cgi, &r->physical.path);
 	if (NULL == ds) return HANDLER_GO_ON;
 
-	st = stat_cache_path_stat(&r->physical.path);
+	/* r->tmp_sce is set in http_response_physical_path_check() and is valid
+	 * in handle_subrequest_start callback -- handle_subrequest_start callbacks
+	 * should not change r->physical.path (or should invalidate r->tmp_sce) */
+	st = r->tmp_sce && buffer_is_equal(&r->tmp_sce->name, &r->physical.path)
+	   ? &r->tmp_sce->st
+	   : stat_cache_path_stat(&r->physical.path);
 	if (NULL == st) return HANDLER_GO_ON;
 
 	/* (aside: CGI might be executable even if it is not readable) */

src/mod_cml.c

@@ -253,7 +253,8 @@ URIHANDLER_FUNC(mod_cml_power_magnet) {
 URIHANDLER_FUNC(mod_cml_is_handled) {
 	plugin_data *p = p_d;
 
-	if (buffer_string_is_empty(&r->physical.path)) return HANDLER_ERROR;
+	/* r->physical.path is non-empty for handle_subrequest_start */
+	/*if (buffer_string_is_empty(&r->physical.path)) return HANDLER_ERROR;*/
 
 	mod_cml_patch_config(r, p);
 

src/mod_dirlisting.c

@@ -1226,7 +1226,8 @@ URIHANDLER_FUNC(mod_dirlisting_subrequest_start) {
 	if (NULL != r->handler_module) return HANDLER_GO_ON;
 	if (!buffer_has_slash_suffix(&r->uri.path)) return HANDLER_GO_ON;
 	if (!http_method_get_or_head(r->http_method)) return HANDLER_GO_ON;
-	if (buffer_string_is_empty(&r->physical.path)) return HANDLER_GO_ON;
+	/* r->physical.path is non-empty for handle_subrequest_start */
+	/*if (buffer_string_is_empty(&r->physical.path)) return HANDLER_GO_ON;*/
 
 	mod_dirlisting_patch_config(r, p);
 
@@ -1239,6 +1240,10 @@ URIHANDLER_FUNC(mod_dirlisting_subrequest_start) {
 		  "URI          : %s", r->uri.path.ptr);
 	}
 
+  #if 0 /* redundant check; not necessary */
+	/* r->physical.path is a dir since it ends in slash, or else
+	 * http_response_physical_path_check() would have redirected
+	 * before calling handle_subrequest_start */
 	if (!stat_cache_path_isdir(&r->physical.path)) {
 		if (errno == ENOTDIR)
 			return HANDLER_GO_ON;
@@ -1246,6 +1251,7 @@ URIHANDLER_FUNC(mod_dirlisting_subrequest_start) {
 		r->http_status = 500;
 		return HANDLER_FINISHED;
 	}
+  #endif
 
 	if (p->conf.cache) {
 		handler_t rc = mod_dirlisting_cache_check(r, p);

src/mod_ssi.c

@@ -1238,7 +1238,8 @@ URIHANDLER_FUNC(mod_ssi_physical_path) {
 	plugin_data *p = p_d;
 
 	if (NULL != r->handler_module) return HANDLER_GO_ON;
-	if (buffer_is_empty(&r->physical.path)) return HANDLER_GO_ON;
+	/* r->physical.path is non-empty for handle_subrequest_start */
+	/*if (buffer_string_is_empty(&r->physical.path)) return HANDLER_GO_ON;*/
 
 	mod_ssi_patch_config(r, p);
 	if (NULL == p->conf.ssi_extension) return HANDLER_GO_ON;

src/mod_staticfile.c

@@ -7,6 +7,7 @@
 #include "plugin.h"
 
 #include "response.h"
+#include "stat_cache.h"
 
 #include <stdlib.h>
 #include <string.h>
@@ -99,10 +100,10 @@ SETDEFAULTS_FUNC(mod_staticfile_set_defaults) {
 URIHANDLER_FUNC(mod_staticfile_subrequest) {
     plugin_data * const p = p_d;
 
-    if (r->http_status != 0) return HANDLER_GO_ON;
-    if (buffer_is_empty(&r->physical.path)) return HANDLER_GO_ON;
     if (NULL != r->handler_module) return HANDLER_GO_ON;
     if (!http_method_get_head_post(r->http_method)) return HANDLER_GO_ON;
+    /* r->physical.path is non-empty for handle_subrequest_start */
+    /*if (buffer_string_is_empty(&r->physical.path)) return HANDLER_GO_ON;*/
 
     mod_staticfile_patch_config(r, p);
 
@@ -127,7 +128,14 @@ URIHANDLER_FUNC(mod_staticfile_subrequest) {
     }
 
     if (!p->conf.etags_used) r->conf.etag_flags = 0;
-    http_response_send_file(r, &r->physical.path);
+
+    /* r->tmp_sce is set in http_response_physical_path_check() and is valid
+     * in handle_subrequest_start callback -- handle_subrequest_start callbacks
+     * should not change r->physical.path (or should invalidate r->tmp_sce) */
+    if (r->tmp_sce && !buffer_is_equal(&r->tmp_sce->name, &r->physical.path))
+        r->tmp_sce = NULL;
+
+    http_response_send_file(r, &r->physical.path, r->tmp_sce);
 
     return HANDLER_FINISHED;
 }

src/request.h

@@ -14,6 +14,7 @@ struct log_error_st;    /* declaration */
 struct chunkqueue;      /* declaration */
 struct cond_cache_t;    /* declaration */
 struct cond_match_t;    /* declaration */
+struct stat_cache_entry;/* declaration */
 
 typedef struct {
     unsigned int http_parseopts;
@@ -191,6 +192,8 @@ struct request_st {
     struct chunkqueue write_queue;     /* HTTP response queue [ file, mem ] */
     struct chunkqueue read_queue;      /* HTTP request queue  [ mem ] */
     struct chunkqueue reqbody_queue; /*(might use tempfiles)*/
+
+    struct stat_cache_entry *tmp_sce; /*(value valid only in sequential code)*/
 };
 
 

src/response.c

@@ -194,9 +194,9 @@ http_response_physical_path_error (request_st * const r, const int code, const c
 
 
 static handler_t http_response_physical_path_check(request_st * const r) {
-	const stat_cache_st *st = stat_cache_path_stat(&r->physical.path);
+	stat_cache_entry *sce = stat_cache_get_entry(&r->physical.path);
 
-	if (st) {
+	if (__builtin_expect( (sce != NULL), 1)) {
 		/* file exists */
 	} else {
 		switch (errno) {
@@ -240,21 +240,23 @@ static handler_t http_response_physical_path_check(request_st * const r) {
 			/*(temporarily modify r->physical.path in-place)*/
 			r->physical.path.used = pathinfo - r->physical.path.ptr + 1;
 			*pathinfo = '\0';
-			const stat_cache_st * const nst = stat_cache_path_stat(&r->physical.path);
+			stat_cache_entry * const nsce = stat_cache_get_entry(&r->physical.path);
 			*pathinfo = '/';
 			r->physical.path.used = pathused;
-			if (NULL == nst) {
+			if (NULL == nsce) {
 				pathinfo = pathinfo != pprev ? pprev : NULL;
 				break;
 			}
-			st = nst;
-			if (!S_ISDIR(st->st_mode)) break;
+			sce = nsce;
+			if (!S_ISDIR(sce->st.st_mode)) break;
 		}
 
-		if (NULL == pathinfo || !S_ISREG(st->st_mode)) {
+		if (NULL == pathinfo || !S_ISREG(sce->st.st_mode)) {
 			/* no it really doesn't exists */
 			return http_response_physical_path_error(r, 404, "-- file not found");
 		}
+		/* note: historical behavior checks S_ISREG() above, permitting
+		 * path-info only on regular files, not dirs or special files */
 
 		/* we have a PATHINFO */
 		if (pathinfo) {
@@ -285,10 +287,16 @@ static handler_t http_response_physical_path_check(request_st * const r) {
 		return http_response_physical_path_error(r, 403, "-- access denied due to symlink restriction");
 	}
 
-	if (S_ISREG(st->st_mode)) /*(common case)*/
+	/* r->tmp_sce is valid in handle_subrequest_start callback --
+	 * handle_subrquest_start callbacks should not change r->physical.path
+	 * (or should invalidate r->tmp_sce).  r->tmp_sce is not reset between
+	 * requests and is valid only for sequential code after this func succeeds*/
+	r->tmp_sce = sce;
+
+	if (S_ISREG(sce->st.st_mode)) /*(common case)*/
 		return HANDLER_GO_ON;
 
-	if (S_ISDIR(st->st_mode)) {
+	if (S_ISDIR(sce->st.st_mode)) {
 		if (!buffer_has_slash_suffix(&r->uri.path)) {
 			http_response_redirect_to_directory(r, 301);
 			return HANDLER_FINISHED;
@@ -569,7 +577,7 @@ http_response_prepare (request_st * const r)
 	/*
 	 * No module grabbed the request yet (like mod_access)
 	 *
-	 * Go on and check of the file exists at all
+	 * Go on and check if the file exists at all
 	 */
 
 		if (r->conf.log_request_handling) {
@@ -582,6 +590,8 @@ http_response_prepare (request_st * const r)
 		rc = http_response_physical_path_check(r);
 		if (HANDLER_GO_ON != rc) continue;
 
+		/* r->physical.path is non-empty and exists in the filesystem */
+
 		if (r->conf.log_request_handling) {
 			log_error(r->conf.errh, __FILE__, __LINE__,
 			  "-- handling subrequest");

src/response.h

@@ -8,6 +8,8 @@
 #include "buffer.h"
 #include "array.h"
 
+struct stat_cache_entry;/* declaration */
+
 int http_response_parse(server *srv, request_st *r);
 
 enum {
@@ -47,7 +49,7 @@ const buffer * http_response_set_last_modified(request_st *r, time_t lmtime);
 int http_response_handle_cachable(request_st *r, const buffer *lmod, time_t lmtime);
 void http_response_body_clear(request_st *r, int preserve_length);
 void http_response_reset(request_st *r);
-void http_response_send_file (request_st *r, buffer *path);
+void http_response_send_file (request_st *r, buffer *path, struct stat_cache_entry *sce);
 void http_response_backend_done (request_st *r);
 void http_response_backend_error (request_st *r);
 void http_response_upgrade_read_body_unknown(request_st *r);