module_ctx.go - Android社区 - https://www.androidos.net.cn/

// 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"
	"path/filepath"
	"text/scanner"

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

// A Module handles generating all of the Ninja build actions needed to build a
// single module based on properties defined in a Blueprints file.  Module
// objects are initially created during the parse phase of a Context using one
// of the registered module types (and the associated ModuleFactory function).
// The Module's properties struct is automatically filled in with the property
// values specified in the Blueprints file (see Context.RegisterModuleType for more
// information on this).
//
// A Module can be split into multiple Modules by a Mutator.  All existing
// properties set on the module will be duplicated to the new Module, and then
// modified as necessary by the Mutator.
//
// The Module implementation can access the build configuration as well as any
// modules on which on which it depends (as defined by the "deps" property
// specified in the Blueprints file, dynamically added by implementing the
// (deprecated) DynamicDependerModule interface, or dynamically added by a
// BottomUpMutator) using the ModuleContext passed to GenerateBuildActions.
// This ModuleContext is also used to create Ninja build actions and to report
// errors to the user.
//
// In addition to implementing the GenerateBuildActions method, a Module should
// implement methods that provide dependant modules and singletons information
// they need to generate their build actions.  These methods will only be called
// after GenerateBuildActions is called because the Context calls
// GenerateBuildActions in dependency-order (and singletons are invoked after
// all the Modules).  The set of methods a Module supports will determine how
// dependant Modules interact with it.
//
// For example, consider a Module that is responsible for generating a library
// that other modules can link against.  The library Module might implement the
// following interface:
//
//   type LibraryProducer interface {
//       LibraryFileName() string
//   }
//
//   func IsLibraryProducer(module blueprint.Module) {
//       _, ok := module.(LibraryProducer)
//       return ok
//   }
//
// A binary-producing Module that depends on the library Module could then do:
//
//   func (m *myBinaryModule) GenerateBuildActions(ctx blueprint.ModuleContext) {
//       ...
//       var libraryFiles []string
//       ctx.VisitDepsDepthFirstIf(IsLibraryProducer,
//           func(module blueprint.Module) {
//               libProducer := module.(LibraryProducer)
//               libraryFiles = append(libraryFiles, libProducer.LibraryFileName())
//           })
//       ...
//   }
//
// to build the list of library file names that should be included in its link
// command.
//
// GenerateBuildActions may be called from multiple threads.  It is guaranteed to
// be called after it has finished being called on all dependencies and on all
// variants of that appear earlier in the ModuleContext.VisitAllModuleVariants list.
// Any accesses to global variables or to Module objects that are not dependencies
// or variants of the current Module must be synchronized by the implementation of
// GenerateBuildActions.
type Module interface {
	// Name returns a string used to uniquely identify each module.  The return
	// value must be unique across all modules.  It is only called once, during
	// initial blueprint parsing.  To change the name later a mutator must call
	// MutatorContext.Rename
	//
	// In most cases, Name should return the contents of a "name:" property from
	// the blueprint file.  An embeddable SimpleName object can be used for this
	// case.
	Name() string

// GenerateBuildActions is called by the Context that created the Module
	// during its generate phase.  This call should generate all Ninja build
	// actions (rules, pools, and build statements) needed to build the module.
	GenerateBuildActions(ModuleContext)
}

// A DynamicDependerModule is a Module that may add dependencies that do not
// appear in its "deps" property.  Any Module that implements this interface
// will have its DynamicDependencies method called by the Context that created
// it during generate phase.
//
// Deprecated, use a BottomUpMutator instead
type DynamicDependerModule interface {
	Module

// DynamicDependencies is called by the Context that created the
	// DynamicDependerModule during its generate phase.  This call should return
	// the list of module names that the DynamicDependerModule depends on
	// dynamically.  Module names that already appear in the "deps" property may
	// but do not need to be included in the returned list.
	DynamicDependencies(DynamicDependerModuleContext) []string
}

type BaseModuleContext interface {
	ModuleName() string
	ModuleDir() string
	Config() interface{}

ContainsProperty(name string) bool
	Errorf(pos scanner.Position, fmt string, args ...interface{})
	ModuleErrorf(fmt string, args ...interface{})
	PropertyErrorf(property, fmt string, args ...interface{})
	Failed() bool

// GlobWithDeps returns a list of files and directories that match the
	// specified pattern but do not match any of the patterns in excludes.
	// Any directories will have a '/' suffix.  It also adds efficient
	// dependencies to rerun the primary builder whenever a file matching
	// the pattern as added or removed, without rerunning if a file that
	// does not match the pattern is added to a searched directory.
	GlobWithDeps(pattern string, excludes []string) ([]string, error)

Fs() pathtools.FileSystem
	AddNinjaFileDeps(deps ...string)

moduleInfo() *moduleInfo
	error(err error)

Namespace() Namespace
}

type DynamicDependerModuleContext BottomUpMutatorContext

type ModuleContext interface {
	BaseModuleContext

OtherModuleName(m Module) string
	OtherModuleErrorf(m Module, fmt string, args ...interface{})
	OtherModuleDependencyTag(m Module) DependencyTag

GetDirectDepWithTag(name string, tag DependencyTag) Module
	GetDirectDep(name string) (Module, DependencyTag)

VisitDirectDeps(visit func(Module))
	VisitDirectDepsIf(pred func(Module) bool, visit func(Module))
	VisitDepsDepthFirst(visit func(Module))
	VisitDepsDepthFirstIf(pred func(Module) bool, visit func(Module))
	WalkDeps(visit func(Module, Module) bool)

ModuleSubDir() string

Variable(pctx PackageContext, name, value string)
	Rule(pctx PackageContext, name string, params RuleParams, argNames ...string) Rule
	Build(pctx PackageContext, params BuildParams)

PrimaryModule() Module
	FinalModule() Module
	VisitAllModuleVariants(visit func(Module))

GetMissingDependencies() []string
}

var _ BaseModuleContext = (*baseModuleContext)(nil)

type baseModuleContext struct {
	context        *Context
	config         interface{}
	module         *moduleInfo
	errs           []error
	visitingParent *moduleInfo
	visitingDep    depInfo
	ninjaFileDeps  []string
}

func (d *baseModuleContext) moduleInfo() *moduleInfo {
	return d.module
}

func (d *baseModuleContext) ModuleName() string {
	return d.module.Name()
}

func (d *baseModuleContext) ContainsProperty(name string) bool {
	_, ok := d.module.propertyPos[name]
	return ok
}

func (d *baseModuleContext) ModuleDir() string {
	return filepath.Dir(d.module.relBlueprintsFile)
}

func (d *baseModuleContext) Config() interface{} {
	return d.config
}

func (d *baseModuleContext) error(err error) {
	if err != nil {
		d.errs = append(d.errs, err)
	}
}

func (d *baseModuleContext) Errorf(pos scanner.Position,
	format string, args ...interface{}) {

d.error(&BlueprintError{
		Err: fmt.Errorf(format, args...),
		Pos: pos,
	})
}

func (d *baseModuleContext) ModuleErrorf(format string,
	args ...interface{}) {

d.error(&ModuleError{
		BlueprintError: BlueprintError{
			Err: fmt.Errorf(format, args...),
			Pos: d.module.pos,
		},
		module: d.module,
	})
}

func (d *baseModuleContext) PropertyErrorf(property, format string,
	args ...interface{}) {

pos := d.module.propertyPos[property]

if !pos.IsValid() {
		pos = d.module.pos
	}

d.error(&PropertyError{
		ModuleError: ModuleError{
			BlueprintError: BlueprintError{
				Err: fmt.Errorf(format, args...),
				Pos: pos,
			},
			module: d.module,
		},
		property: property,
	})
}

func (d *baseModuleContext) Failed() bool {
	return len(d.errs) > 0
}

func (d *baseModuleContext) GlobWithDeps(pattern string,
	excludes []string) ([]string, error) {
	return d.context.glob(pattern, excludes)
}

func (d *baseModuleContext) Fs() pathtools.FileSystem {
	return d.context.fs
}

func (d *baseModuleContext) Namespace() Namespace {
	return d.context.nameInterface.GetNamespace(newNamespaceContext(d.module))
}

var _ ModuleContext = (*moduleContext)(nil)

type moduleContext struct {
	baseModuleContext
	scope              *localScope
	actionDefs         localBuildActions
	handledMissingDeps bool
}

func (m *baseModuleContext) OtherModuleName(logicModule Module) string {
	module := m.context.moduleInfo[logicModule]
	return module.Name()
}

func (m *baseModuleContext) OtherModuleErrorf(logicModule Module, format string,
	args ...interface{}) {

module := m.context.moduleInfo[logicModule]
	m.errs = append(m.errs, &ModuleError{
		BlueprintError: BlueprintError{
			Err: fmt.Errorf(format, args...),
			Pos: module.pos,
		},
		module: module,
	})
}

func (m *baseModuleContext) OtherModuleDependencyTag(logicModule Module) DependencyTag {
	// fast path for calling OtherModuleDependencyTag from inside VisitDirectDeps
	if logicModule == m.visitingDep.module.logicModule {
		return m.visitingDep.tag
	}

for _, dep := range m.visitingParent.directDeps {
		if dep.module.logicModule == logicModule {
			return dep.tag
		}
	}

return nil
}

// GetDirectDep returns the Module and DependencyTag for the direct dependency with the specified
// name, or nil if none exists.
func (m *baseModuleContext) GetDirectDep(name string) (Module, DependencyTag) {
	for _, dep := range m.module.directDeps {
		if dep.module.Name() == name {
			return dep.module.logicModule, dep.tag
		}
	}

return nil, nil
}

// GetDirectDepWithTag returns the Module the direct dependency with the specified name, or nil if
// none exists.  It panics if the dependency does not have the specified tag.
func (m *baseModuleContext) GetDirectDepWithTag(name string, tag DependencyTag) Module {
	for _, dep := range m.module.directDeps {
		if dep.module.Name() == name {
			if dep.tag != tag {
				panic(fmt.Errorf("found dependency %q with tag %#v, expected tag %#v",
					dep.module, dep.tag, tag))
			}
			return dep.module.logicModule
		}
	}

return nil
}

func (m *baseModuleContext) VisitDirectDeps(visit func(Module)) {
	defer func() {
		if r := recover(); r != nil {
			panic(newPanicErrorf(r, "VisitDirectDeps(%s, %s) for dependency %s",
				m.module, funcName(visit), m.visitingDep.module))
		}
	}()

m.visitingParent = m.module

for _, dep := range m.module.directDeps {
		m.visitingDep = dep
		visit(dep.module.logicModule)
	}