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1// Copyright 2016 Google Inc. All rights reserved.
2//
3// Licensed under the Apache License, Version 2.0 (the "License");
4// you may not use this file except in compliance with the License.
5// You may obtain a copy of the License at
6//
7//     http://www.apache.org/licenses/LICENSE-2.0
8//
9// Unless required by applicable law or agreed to in writing, software
10// distributed under the License is distributed on an "AS IS" BASIS,
11// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
12// See the License for the specific language governing permissions and
13// limitations under the License.
14
15package android
16
17import (
18	"fmt"
19
20	"github.com/google/blueprint"
21	"github.com/google/blueprint/proptools"
22)
23
24// This file implements common functionality for handling modules that may exist as prebuilts,
25// source, or both.
26
27type prebuiltDependencyTag struct {
28	blueprint.BaseDependencyTag
29}
30
31var prebuiltDepTag prebuiltDependencyTag
32
33type PrebuiltProperties struct {
34	// When prefer is set to true the prebuilt will be used instead of any source module with
35	// a matching name.
36	Prefer *bool `android:"arch_variant"`
37
38	SourceExists bool `blueprint:"mutated"`
39	UsePrebuilt  bool `blueprint:"mutated"`
40}
41
42type Prebuilt struct {
43	properties PrebuiltProperties
44	module     Module
45	srcs       *[]string
46	src        *string
47}
48
49func (p *Prebuilt) Name(name string) string {
50	return "prebuilt_" + name
51}
52
53func (p *Prebuilt) SingleSourcePath(ctx ModuleContext) Path {
54	if p.srcs != nil {
55		if len(*p.srcs) == 0 {
56			ctx.PropertyErrorf("srcs", "missing prebuilt source file")
57			return nil
58		}
59
60		if len(*p.srcs) > 1 {
61			ctx.PropertyErrorf("srcs", "multiple prebuilt source files")
62			return nil
63		}
64
65		// Return the singleton source after expanding any filegroup in the
66		// sources.
67		return PathForModuleSrc(ctx, (*p.srcs)[0])
68	} else {
69		if proptools.String(p.src) == "" {
70			ctx.PropertyErrorf("src", "missing prebuilt source file")
71			return nil
72		}
73		return PathForModuleSrc(ctx, *p.src)
74	}
75}
76
77func (p *Prebuilt) UsePrebuilt() bool {
78	return p.properties.UsePrebuilt
79}
80
81func InitPrebuiltModule(module PrebuiltInterface, srcs *[]string) {
82	p := module.Prebuilt()
83	module.AddProperties(&p.properties)
84	p.srcs = srcs
85}
86
87func InitSingleSourcePrebuiltModule(module PrebuiltInterface, src *string) {
88	p := module.Prebuilt()
89	module.AddProperties(&p.properties)
90	p.src = src
91}
92
93type PrebuiltInterface interface {
94	Module
95	Prebuilt() *Prebuilt
96}
97
98func RegisterPrebuiltsPreArchMutators(ctx RegisterMutatorsContext) {
99	ctx.BottomUp("prebuilts", PrebuiltMutator).Parallel()
100}
101
102func RegisterPrebuiltsPostDepsMutators(ctx RegisterMutatorsContext) {
103	ctx.TopDown("prebuilt_select", PrebuiltSelectModuleMutator).Parallel()
104	ctx.BottomUp("prebuilt_postdeps", PrebuiltPostDepsMutator).Parallel()
105}
106
107// PrebuiltMutator ensures that there is always a module with an undecorated name, and marks
108// prebuilt modules that have both a prebuilt and a source module.
109func PrebuiltMutator(ctx BottomUpMutatorContext) {
110	if m, ok := ctx.Module().(PrebuiltInterface); ok && m.Prebuilt() != nil {
111		p := m.Prebuilt()
112		name := m.base().BaseModuleName()
113		if ctx.OtherModuleExists(name) {
114			ctx.AddReverseDependency(ctx.Module(), prebuiltDepTag, name)
115			p.properties.SourceExists = true
116		} else {
117			ctx.Rename(name)
118		}
119	}
120}
121
122// PrebuiltSelectModuleMutator marks prebuilts that are used, either overriding source modules or
123// because the source module doesn't exist.  It also disables installing overridden source modules.
124func PrebuiltSelectModuleMutator(ctx TopDownMutatorContext) {
125	if m, ok := ctx.Module().(PrebuiltInterface); ok && m.Prebuilt() != nil {
126		p := m.Prebuilt()
127		if p.srcs == nil && p.src == nil {
128			panic(fmt.Errorf("prebuilt module did not have InitPrebuiltModule called on it"))
129		}
130		if !p.properties.SourceExists {
131			p.properties.UsePrebuilt = p.usePrebuilt(ctx, nil)
132		}
133	} else if s, ok := ctx.Module().(Module); ok {
134		ctx.VisitDirectDepsWithTag(prebuiltDepTag, func(m Module) {
135			p := m.(PrebuiltInterface).Prebuilt()
136			if p.usePrebuilt(ctx, s) {
137				p.properties.UsePrebuilt = true
138				s.SkipInstall()
139			}
140		})
141	}
142}
143
144// PrebuiltPostDepsMutator does two operations.  It replace dependencies on the
145// source module with dependencies on the prebuilt when both modules exist and
146// the prebuilt should be used.  When the prebuilt should not be used, disable
147// installing it.  Secondly, it also adds a sourcegroup to any filegroups found
148// in the prebuilt's 'Srcs' property.
149func PrebuiltPostDepsMutator(ctx BottomUpMutatorContext) {
150	if m, ok := ctx.Module().(PrebuiltInterface); ok && m.Prebuilt() != nil {
151		p := m.Prebuilt()
152		name := m.base().BaseModuleName()
153		if p.properties.UsePrebuilt {
154			if p.properties.SourceExists {
155				ctx.ReplaceDependencies(name)
156			}
157		} else {
158			m.SkipInstall()
159		}
160	}
161}
162
163// usePrebuilt returns true if a prebuilt should be used instead of the source module.  The prebuilt
164// will be used if it is marked "prefer" or if the source module is disabled.
165func (p *Prebuilt) usePrebuilt(ctx TopDownMutatorContext, source Module) bool {
166	if p.srcs != nil && len(*p.srcs) == 0 {
167		return false
168	}
169
170	if p.src != nil && *p.src == "" {
171		return false
172	}
173
174	// TODO: use p.Properties.Name and ctx.ModuleDir to override preference
175	if Bool(p.properties.Prefer) {
176		return true
177	}
178
179	return source == nil || !source.Enabled()
180}
181
182func (p *Prebuilt) SourceExists() bool {
183	return p.properties.SourceExists
184}
185