From 74a660001777308d7a47fdb4b0b3e00979dc5d0e Mon Sep 17 00:00:00 2001
From: Shinichiro Hamaji <shinichiro.hamaji@gmail.com>
Date: Mon, 27 Apr 2015 16:42:30 +0900
Subject: The first step for parallel build

---
 worker.go | 257 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 257 insertions(+)
 create mode 100644 worker.go

(limited to 'worker.go')

diff --git a/worker.go b/worker.go
new file mode 100644
index 0000000..4bd416e
--- /dev/null
+++ b/worker.go
@@ -0,0 +1,257 @@
+package main
+
+import (
+	"fmt"
+	"os/exec"
+	"strings"
+	"syscall"
+	"time"
+)
+
+type Job struct {
+	n        *DepNode
+	ex       *Executor
+	parents  []*Job
+	outputTs int64
+	numDeps  int
+	depsTs   int64
+}
+
+type runner struct {
+	output      string
+	cmd         string
+	echo        bool
+	dryRun      bool
+	ignoreError bool
+	shell       string
+}
+
+func evalCmd(ev *Evaluator, r runner, s string) []runner {
+	r = newRunner(r, s)
+	if strings.IndexByte(r.cmd, '$') < 0 {
+		// fast path
+		return []runner{r}
+	}
+	// TODO(ukai): parse once more earlier?
+	expr, _, err := parseExpr([]byte(r.cmd), nil)
+	if err != nil {
+		panic(fmt.Errorf("parse cmd %q: %v", r.cmd, err))
+	}
+	cmds := string(ev.Value(expr))
+	var runners []runner
+	for _, cmd := range strings.Split(cmds, "\n") {
+		if len(runners) > 0 && strings.HasSuffix(runners[0].cmd, "\\") {
+			runners[0].cmd += "\n"
+			runners[0].cmd += cmd
+		} else {
+			runners = append(runners, newRunner(r, cmd))
+		}
+	}
+	return runners
+}
+
+func newRunner(r runner, s string) runner {
+	for {
+		s = trimLeftSpace(s)
+		if s == "" {
+			return runner{}
+		}
+		switch s[0] {
+		case '@':
+			if !r.dryRun {
+				r.echo = false
+			}
+			s = s[1:]
+			continue
+		case '-':
+			r.ignoreError = true
+			s = s[1:]
+			continue
+		}
+		break
+	}
+	r.cmd = s
+	return r
+}
+
+func (r runner) run(output string) error {
+	if r.echo || dryRunFlag {
+		fmt.Printf("%s\n", r.cmd)
+	}
+	if dryRunFlag {
+		return nil
+	}
+	args := []string{r.shell, "-c", r.cmd}
+	cmd := exec.Cmd{
+		Path: args[0],
+		Args: args,
+	}
+	out, err := cmd.CombinedOutput()
+	fmt.Printf("%s", out)
+	exit := exitStatus(err)
+	if r.ignoreError && exit != 0 {
+		fmt.Printf("[%s] Error %d (ignored)\n", output, exit)
+		err = nil
+	}
+	return err
+}
+
+func (j Job) createRunners() []runner {
+	ex := j.ex
+	// For automatic variables.
+	ex.currentOutput = j.n.Output
+	ex.currentInputs = j.n.ActualInputs
+
+	var restores []func()
+	for k, v := range j.n.TargetSpecificVars {
+		restores = append(restores, ex.vars.save(k))
+		ex.vars[k] = v
+	}
+	defer func() {
+		for _, restore := range restores {
+			restore()
+		}
+	}()
+
+	ev := newEvaluator(ex.vars)
+	ev.filename = j.n.Filename
+	ev.lineno = j.n.Lineno
+	var runners []runner
+	Log("Building: %s cmds:%q", j.n.Output, j.n.Cmds)
+	r := runner{
+		output: j.n.Output,
+		echo:   true,
+		dryRun: dryRunFlag,
+		shell:  ex.shell,
+	}
+	for _, cmd := range j.n.Cmds {
+		for _, r := range evalCmd(ev, r, cmd) {
+			if len(r.cmd) != 0 {
+				runners = append(runners, r)
+			}
+		}
+	}
+	return runners
+}
+
+func (j Job) build() error {
+	if j.n.IsPhony {
+		j.outputTs = -2 // trigger cmd even if all inputs don't exist.
+	} else {
+		j.outputTs = getTimestamp(j.n.Output)
+	}
+
+	if !j.n.HasRule {
+		if j.outputTs >= 0 || j.n.IsPhony {
+			//ex.done[output] = outputTs
+			//ex.noRuleCnt++
+			//return outputTs, nil
+			return nil
+		}
+		if len(j.parents) == 0 {
+			ErrorNoLocation("*** No rule to make target %q.", j.n.Output)
+		} else {
+			ErrorNoLocation("*** No rule to make target %q, needed by %q.", j.n.Output, j.parents[0].n.Output)
+		}
+		return fmt.Errorf("no rule to make target %q", j.n.Output)
+	}
+
+	if j.outputTs >= j.depsTs {
+		// TODO: stats.
+		return nil
+	}
+
+	for _, r := range j.createRunners() {
+		err := r.run(j.n.Output)
+		if err != nil {
+			exit := exitStatus(err)
+			ErrorNoLocation("[%s] Error %d: %v", j.n.Output, exit, err)
+		}
+	}
+
+	if j.n.IsPhony {
+		j.outputTs = time.Now().Unix()
+	} else {
+		j.outputTs = getTimestamp(j.n.Output)
+		if j.outputTs < 0 {
+			j.outputTs = time.Now().Unix()
+		}
+	}
+	return nil
+}
+
+func (j Job) run() error {
+	if err := j.build(); err != nil {
+		return err
+	}
+
+	for _, p := range j.parents {
+		p.numDeps--
+		if p.depsTs < j.outputTs {
+			p.depsTs = j.outputTs
+		}
+		/*
+			if p.numDeps == 0 {
+				p.run()
+			}
+		*/
+	}
+	return nil
+}
+
+type WorkerManager struct {
+	jobs     []*Job
+	jobChan  chan *Job
+	waitChan chan bool
+	doneChan chan bool
+}
+
+func NewWorkerManager() *WorkerManager {
+	wm := &WorkerManager{
+		jobChan:  make(chan *Job),
+		waitChan: make(chan bool),
+		doneChan: make(chan bool),
+	}
+	go wm.Run()
+	return wm
+}
+
+func exitStatus(err error) int {
+	if err == nil {
+		return 0
+	}
+	exit := 1
+	if err, ok := err.(*exec.ExitError); ok {
+		if w, ok := err.ProcessState.Sys().(syscall.WaitStatus); ok {
+			return w.ExitStatus()
+		}
+	}
+	return exit
+}
+
+func (wm *WorkerManager) Run() {
+	done := false
+	for len(wm.jobs) > 0 || !done {
+		select {
+		case j := <-wm.jobChan:
+			if j.numDeps == 0 {
+				err := j.run()
+				if err != nil {
+					exit := exitStatus(err)
+					ErrorNoLocation("[%s] Error %d: %v", j.n.Output, exit, err)
+				}
+			}
+		case done = <-wm.waitChan:
+		}
+	}
+	wm.doneChan <- true
+}
+
+func (wm *WorkerManager) PostJob(j *Job) {
+	wm.jobChan <- j
+}
+
+func (wm *WorkerManager) Wait() {
+	wm.waitChan <- true
+	<-wm.doneChan
+}
-- 
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