initial commit

vendor/github.com/jmoiron/sqlx/bind.go

@@ -0,0 +1,186 @@
+package sqlx
+
+import (
+	"bytes"
+	"errors"
+	"reflect"
+	"strconv"
+	"strings"
+
+	"github.com/jmoiron/sqlx/reflectx"
+)
+
+// Bindvar types supported by Rebind, BindMap and BindStruct.
+const (
+	UNKNOWN = iota
+	QUESTION
+	DOLLAR
+	NAMED
+)
+
+// BindType returns the bindtype for a given database given a drivername.
+func BindType(driverName string) int {
+	switch driverName {
+	case "postgres", "pgx":
+		return DOLLAR
+	case "mysql":
+		return QUESTION
+	case "sqlite3":
+		return QUESTION
+	case "oci8":
+		return NAMED
+	}
+	return UNKNOWN
+}
+
+// FIXME: this should be able to be tolerant of escaped ?'s in queries without
+// losing much speed, and should be to avoid confusion.
+
+// Rebind a query from the default bindtype (QUESTION) to the target bindtype.
+func Rebind(bindType int, query string) string {
+	switch bindType {
+	case QUESTION, UNKNOWN:
+		return query
+	}
+
+	qb := []byte(query)
+	// Add space enough for 10 params before we have to allocate
+	rqb := make([]byte, 0, len(qb)+10)
+	j := 1
+	for _, b := range qb {
+		if b == '?' {
+			switch bindType {
+			case DOLLAR:
+				rqb = append(rqb, '$')
+			case NAMED:
+				rqb = append(rqb, ':', 'a', 'r', 'g')
+			}
+			for _, b := range strconv.Itoa(j) {
+				rqb = append(rqb, byte(b))
+			}
+			j++
+		} else {
+			rqb = append(rqb, b)
+		}
+	}
+	return string(rqb)
+}
+
+// Experimental implementation of Rebind which uses a bytes.Buffer.  The code is
+// much simpler and should be more resistant to odd unicode, but it is twice as
+// slow.  Kept here for benchmarking purposes and to possibly replace Rebind if
+// problems arise with its somewhat naive handling of unicode.
+func rebindBuff(bindType int, query string) string {
+	if bindType != DOLLAR {
+		return query
+	}
+
+	b := make([]byte, 0, len(query))
+	rqb := bytes.NewBuffer(b)
+	j := 1
+	for _, r := range query {
+		if r == '?' {
+			rqb.WriteRune('$')
+			rqb.WriteString(strconv.Itoa(j))
+			j++
+		} else {
+			rqb.WriteRune(r)
+		}
+	}
+
+	return rqb.String()
+}
+
+// In expands slice values in args, returning the modified query string
+// and a new arg list that can be executed by a database. The `query` should
+// use the `?` bindVar.  The return value uses the `?` bindVar.
+func In(query string, args ...interface{}) (string, []interface{}, error) {
+	// argMeta stores reflect.Value and length for slices and
+	// the value itself for non-slice arguments
+	type argMeta struct {
+		v      reflect.Value
+		i      interface{}
+		length int
+	}
+
+	var flatArgsCount int
+	var anySlices bool
+
+	meta := make([]argMeta, len(args))
+
+	for i, arg := range args {
+		v := reflect.ValueOf(arg)
+		t := reflectx.Deref(v.Type())
+
+		if t.Kind() == reflect.Slice {
+			meta[i].length = v.Len()
+			meta[i].v = v
+
+			anySlices = true
+			flatArgsCount += meta[i].length
+
+			if meta[i].length == 0 {
+				return "", nil, errors.New("empty slice passed to 'in' query")
+			}
+		} else {
+			meta[i].i = arg
+			flatArgsCount++
+		}
+	}
+
+	// don't do any parsing if there aren't any slices;  note that this means
+	// some errors that we might have caught below will not be returned.
+	if !anySlices {
+		return query, args, nil
+	}
+
+	newArgs := make([]interface{}, 0, flatArgsCount)
+
+	var arg, offset int
+	var buf bytes.Buffer
+
+	for i := strings.IndexByte(query[offset:], '?'); i != -1; i = strings.IndexByte(query[offset:], '?') {
+		if arg >= len(meta) {
+			// if an argument wasn't passed, lets return an error;  this is
+			// not actually how database/sql Exec/Query works, but since we are
+			// creating an argument list programmatically, we want to be able
+			// to catch these programmer errors earlier.
+			return "", nil, errors.New("number of bindVars exceeds arguments")
+		}
+
+		argMeta := meta[arg]
+		arg++
+
+		// not a slice, continue.
+		// our questionmark will either be written before the next expansion
+		// of a slice or after the loop when writing the rest of the query
+		if argMeta.length == 0 {
+			offset = offset + i + 1
+			newArgs = append(newArgs, argMeta.i)
+			continue
+		}
+
+		// write everything up to and including our ? character
+		buf.WriteString(query[:offset+i+1])
+
+		newArgs = append(newArgs, argMeta.v.Index(0).Interface())
+
+		for si := 1; si < argMeta.length; si++ {
+			buf.WriteString(", ?")
+			newArgs = append(newArgs, argMeta.v.Index(si).Interface())
+		}
+
+		// slice the query and reset the offset. this avoids some bookkeeping for
+		// the write after the loop
+		query = query[offset+i+1:]
+		offset = 0
+	}
+
+	buf.WriteString(query)
+
+	if arg < len(meta) {
+		return "", nil, errors.New("number of bindVars less than number arguments")
+	}
+
+	return buf.String(), newArgs, nil
+}