From 3107a78110309a203b0c2ef7cc4cd9d18d294a46 Mon Sep 17 00:00:00 2001
From: Eric Wong <e@yhbt.net>
Date: Mon, 17 Jan 2011 03:05:42 +0000
Subject: fetch and delete may be passed destination buffer

This allows apps to reduce GC thrashing by reusing
a string buffer.
---
 ext/tdb/tdb.c | 46 ++++++++++++++++++++++++++++++++--------------
 1 file changed, 32 insertions(+), 14 deletions(-)

(limited to 'ext')

diff --git a/ext/tdb/tdb.c b/ext/tdb/tdb.c
index a502d3b..31f71c8 100644
--- a/ext/tdb/tdb.c
+++ b/ext/tdb/tdb.c
@@ -331,7 +331,9 @@ struct fetch_parse_args {
 	struct tdb_context *tdb;
 	union {
 		TDB_DATA key;
-		TDB_DATA val;
+		long value_len;
+		char *value_ptr;
+		VALUE value;
 	} as;
 	VALUE value;
 };
@@ -341,11 +343,12 @@ static VALUE str_new_tdb_data(TDB_DATA *val)
 	return rb_str_new((const char *)val->dptr, val->dsize);
 }
 
-static void *gvl_str_new(void *data)
+static void *gvl_str_resize(void *data)
 {
 	struct fetch_parse_args *f = data;
 
-	f->value = str_new_tdb_data(&f->as.val);
+	rb_str_resize(f->value, f->as.value_len);
+	f->as.value_ptr = RSTRING_PTR(f->value);
 
 	return NULL;
 }
@@ -354,8 +357,10 @@ static int fetch_parse(TDB_DATA key, TDB_DATA val, void *data)
 {
 	struct fetch_parse_args *f = data;
 
-	f->as.val = val;
-	(void)rb_thread_call_with_gvl(gvl_str_new, data);
+	f->as.value_len = val.dsize;
+	(void)rb_thread_call_with_gvl(gvl_str_resize, data);
+	memcpy(f->as.value_ptr, val.dptr, val.dsize);
+	f->as.value = f->value;
 
 	return 0;
 }
@@ -367,16 +372,24 @@ static VALUE nogvl_parse_record(void *ptr)
 	if (tdb_parse_record(f->tdb, f->as.key, fetch_parse, ptr) == -1)
 		return Qnil;
 
-	return f->value;
+	return f->value == f->as.value ? f->value : Qnil;
 }
 
-static VALUE fetch(VALUE self, VALUE key)
+static VALUE fetch(int argc, VALUE *argv, VALUE self)
 {
 	struct fetch_parse_args f;
+	VALUE key;
+
+	rb_scan_args(argc, argv, "11", &key, &f.value);
+	if (NIL_P(f.value)) {
+		f.value = rb_str_new(0, 0);
+	} else {
+		StringValue(f.value);
+		rb_str_set_len(f.value, 0);
+	}
 
 	f.tdb = db(self, 1);
 	TO_TDB_DATA(f.as.key, key);
-	f.value = Qnil;
 
 	return my_tbr(nogvl_parse_record, &f);
 }
@@ -549,12 +562,17 @@ static VALUE nuke(VALUE self, VALUE key)
 	return my_tbr(nogvl_delete, &d);
 }
 
-static VALUE delete(VALUE self, VALUE key)
+static VALUE aref(VALUE self, VALUE key)
+{
+	return fetch(1, &key, self);
+}
+
+static VALUE delete(int argc, VALUE *argv, VALUE self)
 {
-	VALUE rc = fetch(self, key);
+	VALUE rc = fetch(argc, argv, self);
 
 	if (! NIL_P(rc))
-		if (nuke(self, key) == Qfalse)
+		if (nuke(self, argv[0]) == Qfalse)
 			return Qnil;
 	return rc;
 }
@@ -674,8 +692,8 @@ void Init_tdb_ext(void)
 	rb_define_method(cTDB, "close", tdbclose, 0);
 	rb_define_method(cTDB, "closed?", closed, 0);
 
-	rb_define_method(cTDB, "fetch", fetch, 1);
-	rb_define_method(cTDB, "[]", fetch, 1);
+	rb_define_method(cTDB, "fetch", fetch, -1);
+	rb_define_method(cTDB, "[]", aref, 1);
 	rb_define_method(cTDB, "store", store, 2);
 	rb_define_method(cTDB, "[]=", store, 2);
 	rb_define_method(cTDB, "insert!", insert_bang, 2);
@@ -689,7 +707,7 @@ void Init_tdb_ext(void)
 	rb_define_method(cTDB, "member?", has_key, 1);
 	rb_define_method(cTDB, "each", each, 0);
 	rb_define_method(cTDB, "nuke!", nuke, 1);
-	rb_define_method(cTDB, "delete", delete, 1);
+	rb_define_method(cTDB, "delete", delete, -1);
 
 	rb_define_method(cTDB, "lockall", lockall, 0);
 	rb_define_method(cTDB, "trylockall", trylockall, 0);
-- 
cgit v1.2.3-24-ge0c7