bootstrap/glob.go - platform/build/blueprint - Git at Google

 // Copyright 2016 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 bootstrap

 import (
 	"bytes"
 	"fmt"
 	"hash/fnv"
 	"io"
 	"io/ioutil"
 	"path/filepath"
 	"strconv"
 	"strings"

 	"github.com/google/blueprint"
 	"github.com/google/blueprint/pathtools"
 )

 // This file supports globbing source files in Blueprints files.
 //
 // The build.ninja file needs to be regenerated any time a file matching the glob is added
 // or removed.  The naive solution is to have the build.ninja file depend on all the
 // traversed directories, but this will cause the regeneration step to run every time a
 // non-matching file is added to a traversed directory, including backup files created by
 // editors.
 //
 // The solution implemented here optimizes out regenerations when the directory modifications
 // don't match the glob by having the build.ninja file depend on an intermedate file that
 // is only updated when a file matching the glob is added or removed.  The intermediate file
 // depends on the traversed directories via a depfile.  The depfile is used to avoid build
 // errors if a directory is deleted - a direct dependency on the deleted directory would result
 // in a build failure with a "missing and no known rule to make it" error.

 var (
 	globCmd = filepath.Join(bootstrapDir, "bpglob")

 	// globRule rule traverses directories to produce a list of files that match $glob
 	// and writes it to $out if it has changed, and writes the directories to $out.d
 	GlobRule = pctx.StaticRule("GlobRule",
 		blueprint.RuleParams{
 			Command: fmt.Sprintf(`%s -o $out -v %d $args`,
 				globCmd, pathtools.BPGlobArgumentVersion),
 			CommandDeps: []string{globCmd},
 			Description: "glob",

 			Restat:  true,
 			Deps:    blueprint.DepsGCC,
 			Depfile: "$out.d",
 		},
 		"args")
 )

 // GlobFileContext is the subset of ModuleContext and SingletonContext needed by GlobFile
 type GlobFileContext interface {
 	Config() interface{}
 	Build(pctx blueprint.PackageContext, params blueprint.BuildParams)
 }

 // GlobFile creates a rule to write to fileListFile a list of the files that match the specified
 // pattern but do not match any of the patterns specified in excludes.  The file will include
 // appropriate dependencies to regenerate the file if and only if the list of matching files has
 // changed.
 func GlobFile(ctx GlobFileContext, pattern string, excludes []string, fileListFile string) {
 	args := `-p "` + pattern + `"`
 	if len(excludes) > 0 {
 		args += " " + joinWithPrefixAndQuote(excludes, "-e ")
 	}
 	ctx.Build(pctx, blueprint.BuildParams{
 		Rule:    GlobRule,
 		Outputs: []string{fileListFile},
 		Args: map[string]string{
 			"args": args,
 		},
 		Description: "glob " + pattern,
 	})
 }

 // multipleGlobFilesRule creates a rule to write to fileListFile a list of the files that match the specified
 // pattern but do not match any of the patterns specified in excludes.  The file will include
 // appropriate dependencies to regenerate the file if and only if the list of matching files has
 // changed.
 func multipleGlobFilesRule(ctx GlobFileContext, fileListFile string, shard int, globs pathtools.MultipleGlobResults) {
 	args := strings.Builder{}

 	for i, glob := range globs {
 		if i != 0 {
 			args.WriteString(" ")
 		}
 		args.WriteString(`-p "`)
 		args.WriteString(glob.Pattern)
 		args.WriteString(`"`)
 		for _, exclude := range glob.Excludes {
 			args.WriteString(` -e "`)
 			args.WriteString(exclude)
 			args.WriteString(`"`)
 		}
 	}

 	ctx.Build(pctx, blueprint.BuildParams{
 		Rule:    GlobRule,
 		Outputs: []string{fileListFile},
 		Args: map[string]string{
 			"args": args.String(),
 		},
 		Description: fmt.Sprintf("regenerate globs shard %d of %d", shard, numGlobBuckets),
 	})
 }

 func joinWithPrefixAndQuote(strs []string, prefix string) string {
 	if len(strs) == 0 {
 		return ""
 	}

 	if len(strs) == 1 {
 		return prefix + `"` + strs[0] + `"`
 	}

 	n := len(" ") * (len(strs) - 1)
 	for _, s := range strs {
 		n += len(prefix) + len(s) + len(`""`)
 	}

 	ret := make([]byte, 0, n)
 	for i, s := range strs {
 		if i != 0 {
 			ret = append(ret, ' ')
 		}
 		ret = append(ret, prefix...)
 		ret = append(ret, '"')
 		ret = append(ret, s...)
 		ret = append(ret, '"')
 	}
 	return string(ret)
 }

 // GlobSingleton collects any glob patterns that were seen by Context and writes out rules to
 // re-evaluate them whenever the contents of the searched directories change, and retrigger the
 // primary builder if the results change.
 type GlobSingleton struct {
 	// A function that returns the glob results of individual glob buckets
 	GlobLister func() pathtools.MultipleGlobResults

 	// Ninja file that contains instructions for validating the glob list files
 	GlobFile string

 	// Directory containing the glob list files
 	GlobDir string

 	// The source directory
 	SrcDir string
 }

 func globBucketName(globDir string, globBucket int) string {
 	return filepath.Join(globDir, strconv.Itoa(globBucket))
 }

 // Returns the directory where glob list files live
 func GlobDirectory(buildDir, globListDir string) string {
 	return filepath.Join(buildDir, bootstrapSubDir, globListDir)
 }

 func (s *GlobSingleton) GenerateBuildActions(ctx blueprint.SingletonContext) {
 	// Sort the list of globs into buckets.  A hash function is used instead of sharding so that
 	// adding a new glob doesn't force rerunning all the buckets by shifting them all by 1.
 	globBuckets := make([]pathtools.MultipleGlobResults, numGlobBuckets)
 	for _, g := range s.GlobLister() {
 		bucket := globToBucket(g)
 		globBuckets[bucket] = append(globBuckets[bucket], g)
 	}

 	for i, globs := range globBuckets {
 		fileListFile := globBucketName(s.GlobDir, i)

 		// Called from generateGlobNinjaFile.  Write out the file list to disk, and add a ninja
 		// rule to run bpglob if any of the dependencies (usually directories that contain
 		// globbed files) have changed.  The file list produced by bpglob should match exactly
 		// with the file written here so that restat can prevent rerunning the primary builder.
 		//
 		// We need to write the file list here so that it has an older modified date
 		// than the build.ninja (otherwise we'd run the primary builder twice on
 		// every new glob)
 		//
 		// We don't need to write the depfile because we're guaranteed that ninja
 		// will run the command at least once (to record it into the ninja_log), so
 		// the depfile will be loaded from that execution.
 		absoluteFileListFile := joinPath(s.SrcDir, fileListFile)
 		err := pathtools.WriteFileIfChanged(absoluteFileListFile, globs.FileList(), 0666)
 		if err != nil {
 			panic(fmt.Errorf("error writing %s: %s", fileListFile, err))
 		}

 		// Write out the ninja rule to run bpglob.
 		multipleGlobFilesRule(ctx, fileListFile, i, globs)
 	}
 }

 // Writes a .ninja file that contains instructions for regenerating the glob
 // files that contain the results of every glob that was run. The list of files
 // is available as the result of GlobFileListFiles().
 func WriteBuildGlobsNinjaFile(glob *GlobSingleton, config interface{}) {
 	buffer, errs := generateGlobNinjaFile(glob, config)
 	if len(errs) > 0 {
 		fatalErrors(errs)
 	}

 	const outFilePermissions = 0666
 	err := ioutil.WriteFile(joinPath(glob.SrcDir, glob.GlobFile), buffer, outFilePermissions)
 	if err != nil {
 		fatalf("error writing %s: %s", glob.GlobFile, err)
 	}
 }
 func generateGlobNinjaFile(glob *GlobSingleton, config interface{}) ([]byte, []error) {

 	ctx := blueprint.NewContext()
 	ctx.RegisterSingletonType("glob", func() blueprint.Singleton {
 		return glob
 	})

 	extraDeps, errs := ctx.ResolveDependencies(config)
 	if len(extraDeps) > 0 {
 		return nil, []error{fmt.Errorf("shouldn't have extra deps")}
 	}
 	if len(errs) > 0 {
 		return nil, errs
 	}

 	extraDeps, errs = ctx.PrepareBuildActions(config)
 	if len(extraDeps) > 0 {
 		return nil, []error{fmt.Errorf("shouldn't have extra deps")}
 	}
 	if len(errs) > 0 {
 		return nil, errs
 	}

 	buf := bytes.NewBuffer(nil)
 	err := ctx.WriteBuildFile(buf)
 	if err != nil {
 		return nil, []error{err}
 	}

 	return buf.Bytes(), nil
 }

 // GlobFileListFiles returns the list of files that contain the result of globs
 // in the build. It is suitable for inclusion in build.ninja.d (so that
 // build.ninja is regenerated if the globs change). The instructions to
 // regenerate these files are written by WriteBuildGlobsNinjaFile().
 func GlobFileListFiles(globDir string) []string {
 	var fileListFiles []string
 	for i := 0; i < numGlobBuckets; i++ {
 		fileListFile := globBucketName(globDir, i)
 		fileListFiles = append(fileListFiles, fileListFile)
 	}
 	return fileListFiles
 }

 const numGlobBuckets = 1024

 // globToBucket converts a pathtools.GlobResult into a hashed bucket number in the range
 // [0, numGlobBuckets).
 func globToBucket(g pathtools.GlobResult) int {
 	hash := fnv.New32a()
 	io.WriteString(hash, g.Pattern)
 	for _, e := range g.Excludes {
 		io.WriteString(hash, e)
 	}
 	return int(hash.Sum32() % numGlobBuckets)
 }
	// Copyright 2016 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 bootstrap

	import (
	"bytes"
	"fmt"
	"hash/fnv"
	"io"
	"io/ioutil"
	"path/filepath"
	"strconv"
	"strings"

	"github.com/google/blueprint"
	"github.com/google/blueprint/pathtools"
	)

	// This file supports globbing source files in Blueprints files.
	//
	// The build.ninja file needs to be regenerated any time a file matching the glob is added
	// or removed. The naive solution is to have the build.ninja file depend on all the
	// traversed directories, but this will cause the regeneration step to run every time a
	// non-matching file is added to a traversed directory, including backup files created by
	// editors.
	//
	// The solution implemented here optimizes out regenerations when the directory modifications
	// don't match the glob by having the build.ninja file depend on an intermedate file that
	// is only updated when a file matching the glob is added or removed. The intermediate file
	// depends on the traversed directories via a depfile. The depfile is used to avoid build
	// errors if a directory is deleted - a direct dependency on the deleted directory would result
	// in a build failure with a "missing and no known rule to make it" error.

	var (
	globCmd = filepath.Join(bootstrapDir, "bpglob")

	// globRule rule traverses directories to produce a list of files that match $glob
	// and writes it to $out if it has changed, and writes the directories to $out.d
	GlobRule = pctx.StaticRule("GlobRule",
	blueprint.RuleParams{
	Command: fmt.Sprintf(`%s -o $out -v %d $args`,
	globCmd, pathtools.BPGlobArgumentVersion),
	CommandDeps: []string{globCmd},
	Description: "glob",

	Restat: true,
	Deps: blueprint.DepsGCC,
	Depfile: "$out.d",
	},
	"args")
	)

	// GlobFileContext is the subset of ModuleContext and SingletonContext needed by GlobFile
	type GlobFileContext interface {
	Config() interface{}
	Build(pctx blueprint.PackageContext, params blueprint.BuildParams)
	}

	// GlobFile creates a rule to write to fileListFile a list of the files that match the specified
	// pattern but do not match any of the patterns specified in excludes. The file will include
	// appropriate dependencies to regenerate the file if and only if the list of matching files has
	// changed.
	func GlobFile(ctx GlobFileContext, pattern string, excludes []string, fileListFile string) {
	args := `-p "` + pattern + `"`
	if len(excludes) > 0 {
	args += " " + joinWithPrefixAndQuote(excludes, "-e ")
	}
	ctx.Build(pctx, blueprint.BuildParams{
	Rule: GlobRule,
	Outputs: []string{fileListFile},
	Args: map[string]string{
	"args": args,
	},
	Description: "glob " + pattern,
	})
	}

	// multipleGlobFilesRule creates a rule to write to fileListFile a list of the files that match the specified
	// pattern but do not match any of the patterns specified in excludes. The file will include
	// appropriate dependencies to regenerate the file if and only if the list of matching files has
	// changed.
	func multipleGlobFilesRule(ctx GlobFileContext, fileListFile string, shard int, globs pathtools.MultipleGlobResults) {
	args := strings.Builder{}

	for i, glob := range globs {
	if i != 0 {
	args.WriteString(" ")
	}
	args.WriteString(`-p "`)
	args.WriteString(glob.Pattern)
	args.WriteString(`"`)
	for _, exclude := range glob.Excludes {
	args.WriteString(` -e "`)
	args.WriteString(exclude)
	args.WriteString(`"`)
	}
	}

	ctx.Build(pctx, blueprint.BuildParams{
	Rule: GlobRule,
	Outputs: []string{fileListFile},
	Args: map[string]string{
	"args": args.String(),
	},
	Description: fmt.Sprintf("regenerate globs shard %d of %d", shard, numGlobBuckets),
	})
	}

	func joinWithPrefixAndQuote(strs []string, prefix string) string {
	if len(strs) == 0 {
	return ""
	}

	if len(strs) == 1 {
	return prefix + `"` + strs[0] + `"`
	}

	n := len(" ") * (len(strs) - 1)
	for _, s := range strs {
	n += len(prefix) + len(s) + len(`""`)
	}

	ret := make([]byte, 0, n)
	for i, s := range strs {
	if i != 0 {
	ret = append(ret, ' ')
	}
	ret = append(ret, prefix...)
	ret = append(ret, '"')
	ret = append(ret, s...)
	ret = append(ret, '"')
	}
	return string(ret)
	}

	// GlobSingleton collects any glob patterns that were seen by Context and writes out rules to
	// re-evaluate them whenever the contents of the searched directories change, and retrigger the
	// primary builder if the results change.
	type GlobSingleton struct {
	// A function that returns the glob results of individual glob buckets
	GlobLister func() pathtools.MultipleGlobResults

	// Ninja file that contains instructions for validating the glob list files
	GlobFile string

	// Directory containing the glob list files
	GlobDir string

	// The source directory
	SrcDir string
	}

	func globBucketName(globDir string, globBucket int) string {
	return filepath.Join(globDir, strconv.Itoa(globBucket))
	}

	// Returns the directory where glob list files live
	func GlobDirectory(buildDir, globListDir string) string {
	return filepath.Join(buildDir, bootstrapSubDir, globListDir)
	}

	func (s *GlobSingleton) GenerateBuildActions(ctx blueprint.SingletonContext) {
	// Sort the list of globs into buckets. A hash function is used instead of sharding so that
	// adding a new glob doesn't force rerunning all the buckets by shifting them all by 1.
	globBuckets := make([]pathtools.MultipleGlobResults, numGlobBuckets)
	for _, g := range s.GlobLister() {
	bucket := globToBucket(g)
	globBuckets[bucket] = append(globBuckets[bucket], g)
	}

	for i, globs := range globBuckets {
	fileListFile := globBucketName(s.GlobDir, i)

	// Called from generateGlobNinjaFile. Write out the file list to disk, and add a ninja
	// rule to run bpglob if any of the dependencies (usually directories that contain
	// globbed files) have changed. The file list produced by bpglob should match exactly
	// with the file written here so that restat can prevent rerunning the primary builder.
	//
	// We need to write the file list here so that it has an older modified date
	// than the build.ninja (otherwise we'd run the primary builder twice on
	// every new glob)
	//
	// We don't need to write the depfile because we're guaranteed that ninja
	// will run the command at least once (to record it into the ninja_log), so
	// the depfile will be loaded from that execution.
	absoluteFileListFile := joinPath(s.SrcDir, fileListFile)
	err := pathtools.WriteFileIfChanged(absoluteFileListFile, globs.FileList(), 0666)
	if err != nil {
	panic(fmt.Errorf("error writing %s: %s", fileListFile, err))
	}

	// Write out the ninja rule to run bpglob.
	multipleGlobFilesRule(ctx, fileListFile, i, globs)
	}
	}

	// Writes a .ninja file that contains instructions for regenerating the glob
	// files that contain the results of every glob that was run. The list of files
	// is available as the result of GlobFileListFiles().
	func WriteBuildGlobsNinjaFile(glob *GlobSingleton, config interface{}) {
	buffer, errs := generateGlobNinjaFile(glob, config)
	if len(errs) > 0 {
	fatalErrors(errs)
	}

	const outFilePermissions = 0666
	err := ioutil.WriteFile(joinPath(glob.SrcDir, glob.GlobFile), buffer, outFilePermissions)
	if err != nil {
	fatalf("error writing %s: %s", glob.GlobFile, err)
	}
	}
	func generateGlobNinjaFile(glob *GlobSingleton, config interface{}) ([]byte, []error) {

	ctx := blueprint.NewContext()
	ctx.RegisterSingletonType("glob", func() blueprint.Singleton {
	return glob
	})

	extraDeps, errs := ctx.ResolveDependencies(config)
	if len(extraDeps) > 0 {
	return nil, []error{fmt.Errorf("shouldn't have extra deps")}
	}
	if len(errs) > 0 {
	return nil, errs
	}

	extraDeps, errs = ctx.PrepareBuildActions(config)
	if len(extraDeps) > 0 {
	return nil, []error{fmt.Errorf("shouldn't have extra deps")}
	}
	if len(errs) > 0 {
	return nil, errs
	}

	buf := bytes.NewBuffer(nil)
	err := ctx.WriteBuildFile(buf)
	if err != nil {
	return nil, []error{err}
	}

	return buf.Bytes(), nil
	}

	// GlobFileListFiles returns the list of files that contain the result of globs
	// in the build. It is suitable for inclusion in build.ninja.d (so that
	// build.ninja is regenerated if the globs change). The instructions to
	// regenerate these files are written by WriteBuildGlobsNinjaFile().
	func GlobFileListFiles(globDir string) []string {
	var fileListFiles []string
	for i := 0; i < numGlobBuckets; i++ {
	fileListFile := globBucketName(globDir, i)
	fileListFiles = append(fileListFiles, fileListFile)
	}
	return fileListFiles
	}

	const numGlobBuckets = 1024

	// globToBucket converts a pathtools.GlobResult into a hashed bucket number in the range
	// [0, numGlobBuckets).
	func globToBucket(g pathtools.GlobResult) int {
	hash := fnv.New32a()
	io.WriteString(hash, g.Pattern)
	for _, e := range g.Excludes {
	io.WriteString(hash, e)
	}
	return int(hash.Sum32() % numGlobBuckets)
	}