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// Copyright 2015 Google Inc. All rights reserved
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
package main
import (
"bytes"
"errors"
"strings"
)
type pattern struct {
prefix, suffix string
}
func (p pattern) String() string {
return p.prefix + "%" + p.suffix
}
func (p pattern) match(s string) bool {
return strings.HasPrefix(s, p.prefix) && strings.HasSuffix(s, p.suffix)
}
func (p pattern) subst(repl, str string) string {
in := str
trimed := str
if p.prefix != "" {
trimed = strings.TrimPrefix(in, p.prefix)
if trimed == in {
return str
}
}
in = trimed
if p.suffix != "" {
trimed = strings.TrimSuffix(in, p.suffix)
if trimed == in {
return str
}
}
rs := strings.SplitN(repl, "%", 2)
if len(rs) != 2 {
return repl
}
return rs[0] + trimed + rs[1]
}
type Rule struct {
outputs []string
inputs []string
orderOnlyInputs []string
outputPatterns []pattern
isDoubleColon bool
isSuffixRule bool
cmds []string
filename string
lineno int
cmdLineno int
}
func isPatternRule(s []byte) (pattern, bool) {
i := bytes.IndexByte(s, '%')
if i < 0 {
return pattern{}, false
}
return pattern{prefix: string(s[:i]), suffix: string(s[i+1:])}, true
}
func (r *Rule) parseInputs(s []byte) {
ws := newWordScanner(s)
isOrderOnly := false
for ws.Scan() {
input := ws.Bytes()
if len(input) == 1 && input[0] == '|' {
isOrderOnly = true
continue
}
if isOrderOnly {
r.orderOnlyInputs = append(r.orderOnlyInputs, internBytes(input))
} else {
r.inputs = append(r.inputs, internBytes(input))
}
}
}
func (r *Rule) parseVar(s []byte) *AssignAST {
eq := bytes.IndexByte(s, '=')
if eq <= 0 {
return nil
}
rhs := trimLeftSpaceBytes(s[eq+1:])
var lhs []byte
var op string
// TODO(ukai): support override, export.
switch s[eq-1] { // s[eq] is '='
case ':':
lhs = trimSpaceBytes(s[:eq-1])
op = ":="
case '+':
lhs = trimSpaceBytes(s[:eq-1])
op = "+="
case '?':
lhs = trimSpaceBytes(s[:eq-1])
op = "?="
default:
lhs = trimSpaceBytes(s[:eq])
op = "="
}
assign := newAssignAST(nil, lhs, rhs, op)
assign.filename = r.filename
assign.lineno = r.lineno
return assign
}
func (r *Rule) parse(line []byte) (*AssignAST, error) {
index := bytes.IndexByte(line, ':')
if index < 0 {
return nil, errors.New("*** missing separator.")
}
first := line[:index]
ws := newWordScanner(first)
pat, isFirstPattern := isPatternRule(first)
if isFirstPattern {
n := 0
for ws.Scan() {
n++
if n > 1 {
return nil, errors.New("*** mixed implicit and normal rules: deprecated syntax")
}
}
r.outputPatterns = []pattern{pat}
} else {
for ws.Scan() {
r.outputs = append(r.outputs, internBytes(ws.Bytes()))
}
}
index++
if index < len(line) && line[index] == ':' {
r.isDoubleColon = true
index++
}
rest := line[index:]
if assign := r.parseVar(rest); assign != nil {
return assign, nil
}
index = bytes.IndexByte(rest, ':')
if index < 0 {
r.parseInputs(rest)
return nil, nil
}
// %.x: %.y: %.z
if isFirstPattern {
return nil, errors.New("*** mixed implicit and normal rules: deprecated syntax")
}
second := rest[:index]
third := rest[index+1:]
// r.outputs is already set.
ws = newWordScanner(second)
if !ws.Scan() {
return nil, errors.New("*** missing target pattern.")
}
outpat, ok := isPatternRule(ws.Bytes())
if !ok {
return nil, errors.New("*** target pattern contains no '%'.")
}
r.outputPatterns = []pattern{outpat}
if ws.Scan() {
return nil, errors.New("*** multiple target patterns.")
}
r.parseInputs(third)
return nil, nil
}
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