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// +build go1.8
package squirrel
import (
"context"
"database/sql"
)
// PrepareerContext is the interface that wraps the Prepare and PrepareContext methods.
//
// Prepare executes the given query as implemented by database/sql.Prepare.
// PrepareContext executes the given query as implemented by database/sql.PrepareContext.
type PreparerContext interface {
Preparer
PrepareContext(ctx context.Context, query string) (*sql.Stmt, error)
}
// DBProxyContext groups the Execer, Queryer, QueryRower and PreparerContext interfaces.
type DBProxyContext interface {
Execer
Queryer
QueryRower
PreparerContext
}
// NewStmtCache returns a *StmtCache wrapping a PreparerContext that caches Prepared Stmts.
//
// Stmts are cached based on the string value of their queries.
func NewStmtCache(prep PreparerContext) *StmtCache {
return &StmtCache{prep: prep, cache: make(map[string]*sql.Stmt)}
}
// NewStmtCacher is deprecated
//
// Use NewStmtCache instead
func NewStmtCacher(prep PreparerContext) DBProxyContext {
return NewStmtCache(prep)
}
// PrepareContext delegates down to the underlying PreparerContext and caches the result
// using the provided query as a key
func (sc *StmtCache) PrepareContext(ctx context.Context, query string) (*sql.Stmt, error) {
ctxPrep, ok := sc.prep.(PreparerContext)
if !ok {
return nil, NoContextSupport
}
sc.mu.Lock()
defer sc.mu.Unlock()
stmt, ok := sc.cache[query]
if ok {
return stmt, nil
}
stmt, err := ctxPrep.PrepareContext(ctx, query)
if err == nil {
sc.cache[query] = stmt
}
return stmt, err
}
// ExecContext delegates down to the underlying PreparerContext using a prepared statement
func (sc *StmtCache) ExecContext(ctx context.Context, query string, args ...interface{}) (res sql.Result, err error) {
stmt, err := sc.PrepareContext(ctx, query)
if err != nil {
return
}
return stmt.ExecContext(ctx, args...)
}
// QueryContext delegates down to the underlying PreparerContext using a prepared statement
func (sc *StmtCache) QueryContext(ctx context.Context, query string, args ...interface{}) (rows *sql.Rows, err error) {
stmt, err := sc.PrepareContext(ctx, query)
if err != nil {
return
}
return stmt.QueryContext(ctx, args...)
}
// QueryRowContext delegates down to the underlying PreparerContext using a prepared statement
func (sc *StmtCache) QueryRowContext(ctx context.Context, query string, args ...interface{}) RowScanner {
stmt, err := sc.PrepareContext(ctx, query)
if err != nil {
return &Row{err: err}
}
return stmt.QueryRowContext(ctx, args...)
}
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