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// Copyright 2014 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 blueprint
import (
"fmt"
"io"
"strings"
"unicode"
)
const (
indentWidth = 4
maxIndentDepth = 2
lineWidth = 80
)
var indentString = strings.Repeat(" ", indentWidth*maxIndentDepth)
type ninjaWriter struct {
writer io.Writer
justDidBlankLine bool // true if the last operation was a BlankLine
}
func newNinjaWriter(writer io.Writer) *ninjaWriter {
return &ninjaWriter{
writer: writer,
}
}
func (n *ninjaWriter) Comment(comment string) error {
n.justDidBlankLine = false
const lineHeaderLen = len("# ")
const maxLineLen = lineWidth - lineHeaderLen
var lineStart, lastSplitPoint int
for i, r := range comment {
if unicode.IsSpace(r) {
// We know we can safely split the line here.
lastSplitPoint = i + 1
}
var line string
var writeLine bool
switch {
case r == '\n':
// Output the line without trimming the left so as to allow comments
// to contain their own indentation.
line = strings.TrimRightFunc(comment[lineStart:i], unicode.IsSpace)
writeLine = true
case (i-lineStart > maxLineLen) && (lastSplitPoint > lineStart):
// The line has grown too long and is splittable. Split it at the
// last split point.
line = strings.TrimSpace(comment[lineStart:lastSplitPoint])
writeLine = true
}
if writeLine {
line = strings.TrimSpace("# "+line) + "\n"
_, err := io.WriteString(n.writer, line)
if err != nil {
return err
}
lineStart = lastSplitPoint
}
}
if lineStart != len(comment) {
line := strings.TrimSpace(comment[lineStart:])
_, err := fmt.Fprintf(n.writer, "# %s\n", line)
if err != nil {
return err
}
}
return nil
}
func (n *ninjaWriter) Pool(name string) error {
n.justDidBlankLine = false
_, err := fmt.Fprintf(n.writer, "pool %s\n", name)
return err
}
func (n *ninjaWriter) Rule(name string) error {
n.justDidBlankLine = false
_, err := fmt.Fprintf(n.writer, "rule %s\n", name)
return err
}
func (n *ninjaWriter) Build(comment string, rule string, outputs, explicitDeps, implicitDeps,
orderOnlyDeps []string) error {
n.justDidBlankLine = false
const lineWrapLen = len(" $")
const maxLineLen = lineWidth - lineWrapLen
wrapper := ninjaWriterWithWrap{
ninjaWriter: n,
maxLineLen: maxLineLen,
}
if comment != "" {
wrapper.Comment(comment)
}
wrapper.WriteString("build")
for _, output := range outputs {
wrapper.WriteStringWithSpace(output)
}
wrapper.WriteString(":")
wrapper.WriteStringWithSpace(rule)
for _, dep := range explicitDeps {
wrapper.WriteStringWithSpace(dep)
}
if len(implicitDeps) > 0 {
wrapper.WriteStringWithSpace("|")
for _, dep := range implicitDeps {
wrapper.WriteStringWithSpace(dep)
}
}
if len(orderOnlyDeps) > 0 {
wrapper.WriteStringWithSpace("||")
for _, dep := range orderOnlyDeps {
wrapper.WriteStringWithSpace(dep)
}
}
return wrapper.Flush()
}
func (n *ninjaWriter) Assign(name, value string) error {
n.justDidBlankLine = false
_, err := fmt.Fprintf(n.writer, "%s = %s\n", name, value)
return err
}
func (n *ninjaWriter) ScopedAssign(name, value string) error {
n.justDidBlankLine = false
_, err := fmt.Fprintf(n.writer, "%s%s = %s\n", indentString[:indentWidth], name, value)
return err
}
func (n *ninjaWriter) Default(targets ...string) error {
n.justDidBlankLine = false
const lineWrapLen = len(" $")
const maxLineLen = lineWidth - lineWrapLen
wrapper := ninjaWriterWithWrap{
ninjaWriter: n,
maxLineLen: maxLineLen,
}
wrapper.WriteString("default")
for _, target := range targets {
wrapper.WriteString(" " + target)
}
return wrapper.Flush()
}
func (n *ninjaWriter) BlankLine() (err error) {
// We don't output multiple blank lines in a row.
if !n.justDidBlankLine {
n.justDidBlankLine = true
_, err = io.WriteString(n.writer, "\n")
}
return err
}
type ninjaWriterWithWrap struct {
*ninjaWriter
maxLineLen int
writtenLen int
err error
}
func (n *ninjaWriterWithWrap) writeString(s string, space bool) {
if n.err != nil {
return
}
spaceLen := 0
if space {
spaceLen = 1
}
if n.writtenLen+len(s)+spaceLen > n.maxLineLen {
_, n.err = io.WriteString(n.writer, " $\n")
if n.err != nil {
return
}
_, n.err = io.WriteString(n.writer, indentString[:indentWidth*2])
if n.err != nil {
return
}
n.writtenLen = indentWidth * 2
s = strings.TrimLeftFunc(s, unicode.IsSpace)
} else if space {
io.WriteString(n.writer, " ")
n.writtenLen++
}
_, n.err = io.WriteString(n.writer, s)
n.writtenLen += len(s)
}
func (n *ninjaWriterWithWrap) WriteString(s string) {
n.writeString(s, false)
}
func (n *ninjaWriterWithWrap) WriteStringWithSpace(s string) {
n.writeString(s, true)
}
func (n *ninjaWriterWithWrap) Flush() error {
if n.err != nil {
return n.err
}
_, err := io.WriteString(n.writer, "\n")
return err
}