database/sql: use method values instead of generating closures

Reduces garbage.

R=adg, r
CC=dsymonds, gobot, golang-dev
https://golang.org/cl/9088045

diff --git a/src/pkg/database/sql/sql.go b/src/pkg/database/sql/sql.go
index a80782bfedc87049f9b03efad253a9602576b031..968cb7475295718af37adb4b4f55d5acc338d71e 100644 (file)
--- a/src/pkg/database/sql/sql.go
+++ b/src/pkg/database/sql/sql.go
@@ -219,6 +219,10 @@ type driverConn struct {
        dbmuClosed bool     // same as closed, but guarded by db.mu, for connIfFree
 }
 
+func (dc *driverConn) releaseConn(err error) {
+       dc.db.putConn(dc, err)
+}
+
 func (dc *driverConn) removeOpenStmt(si driver.Stmt) {
        dc.Lock()
        defer dc.Unlock()
@@ -367,10 +371,7 @@ func (db *DB) removeDepLocked(x finalCloser, dep interface{}) func() error {
        if !done {
                return func() error { return nil }
        }
-       return func() error {
-               //println(fmt.Sprintf("calling final close on %T %v (%#v)", x, x, x))
-               return x.finalClose()
-       }
+       return x.finalClose
 }
 
 // Open opens a database specified by its database driver name and a
@@ -710,9 +711,7 @@ func (db *DB) query(query string, args []interface{}) (*Rows, error) {
                return nil, err
        }
 
-       releaseConn := func(err error) { db.putConn(ci, err) }
-
-       return db.queryConn(ci, releaseConn, query, args)
+       return db.queryConn(ci, ci.releaseConn, query, args)
 }
 
 // queryConn executes a query on the given connection.
@@ -1154,8 +1153,7 @@ func (s *Stmt) connStmt() (ci *driverConn, releaseConn func(error), si driver.St
        }
 
        conn := cs.dc
-       releaseConn = func(err error) { s.db.putConn(conn, err) }
-       return conn, releaseConn, cs.si, nil
+       return conn, conn.releaseConn, cs.si, nil
 }
 
 // Query executes a prepared query statement with the given arguments