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1// Copyright 2015 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	"reflect"
19
20	"github.com/google/blueprint"
21	"github.com/google/blueprint/proptools"
22)
23
24type defaultsDependencyTag struct {
25	blueprint.BaseDependencyTag
26}
27
28var DefaultsDepTag defaultsDependencyTag
29
30type defaultsProperties struct {
31	Defaults []string
32}
33
34type DefaultableModuleBase struct {
35	defaultsProperties            defaultsProperties
36	defaultableProperties         []interface{}
37	defaultableVariableProperties interface{}
38
39	// The optional hook to call after any defaults have been applied.
40	hook DefaultableHook
41}
42
43func (d *DefaultableModuleBase) defaults() *defaultsProperties {
44	return &d.defaultsProperties
45}
46
47func (d *DefaultableModuleBase) setProperties(props []interface{}, variableProperties interface{}) {
48	d.defaultableProperties = props
49	d.defaultableVariableProperties = variableProperties
50}
51
52func (d *DefaultableModuleBase) SetDefaultableHook(hook DefaultableHook) {
53	d.hook = hook
54}
55
56func (d *DefaultableModuleBase) CallHookIfAvailable(ctx DefaultableHookContext) {
57	if d.hook != nil {
58		d.hook(ctx)
59	}
60}
61
62// Interface that must be supported by any module to which defaults can be applied.
63type Defaultable interface {
64	// Get a pointer to the struct containing the Defaults property.
65	defaults() *defaultsProperties
66
67	// Set the property structures into which defaults will be added.
68	setProperties(props []interface{}, variableProperties interface{})
69
70	// Apply defaults from the supplied Defaults to the property structures supplied to
71	// setProperties(...).
72	applyDefaults(TopDownMutatorContext, []Defaults)
73
74	// Set the hook to be called after any defaults have been applied.
75	//
76	// Should be used in preference to a AddLoadHook when the behavior of the load
77	// hook is dependent on properties supplied in the Android.bp file.
78	SetDefaultableHook(hook DefaultableHook)
79
80	// Call the hook if specified.
81	CallHookIfAvailable(context DefaultableHookContext)
82}
83
84type DefaultableModule interface {
85	Module
86	Defaultable
87}
88
89var _ Defaultable = (*DefaultableModuleBase)(nil)
90
91func InitDefaultableModule(module DefaultableModule) {
92	if module.base().module == nil {
93		panic("InitAndroidModule must be called before InitDefaultableModule")
94	}
95
96	module.setProperties(module.GetProperties(), module.base().variableProperties)
97
98	module.AddProperties(module.defaults())
99}
100
101// A restricted subset of context methods, similar to LoadHookContext.
102type DefaultableHookContext interface {
103	EarlyModuleContext
104
105	CreateModule(ModuleFactory, ...interface{}) Module
106	AddMissingDependencies(missingDeps []string)
107}
108
109type DefaultableHook func(ctx DefaultableHookContext)
110
111// The Defaults_visibility property.
112type DefaultsVisibilityProperties struct {
113
114	// Controls the visibility of the defaults module itself.
115	Defaults_visibility []string
116}
117
118type DefaultsModuleBase struct {
119	DefaultableModuleBase
120}
121
122// The common pattern for defaults modules is to register separate instances of
123// the xxxProperties structs in the AddProperties calls, rather than reusing the
124// ones inherited from Module.
125//
126// The effect is that e.g. myDefaultsModuleInstance.base().xxxProperties won't
127// contain the values that have been set for the defaults module. Rather, to
128// retrieve the values it is necessary to iterate over properties(). E.g. to get
129// the commonProperties instance that have the real values:
130//
131//	d := myModule.(Defaults)
132//	for _, props := range d.properties() {
133//	  if cp, ok := props.(*commonProperties); ok {
134//	    ... access property values in cp ...
135//	  }
136//	}
137//
138// The rationale is that the properties on a defaults module apply to the
139// defaultable modules using it, not to the defaults module itself. E.g. setting
140// the "enabled" property false makes inheriting modules disabled by default,
141// rather than disabling the defaults module itself.
142type Defaults interface {
143	Defaultable
144
145	// Although this function is unused it is actually needed to ensure that only modules that embed
146	// DefaultsModuleBase will type-assert to the Defaults interface.
147	isDefaults() bool
148
149	// Get the structures containing the properties for which defaults can be provided.
150	properties() []interface{}
151
152	productVariableProperties() interface{}
153}
154
155func (d *DefaultsModuleBase) isDefaults() bool {
156	return true
157}
158
159type DefaultsModule interface {
160	Module
161	Defaults
162}
163
164func (d *DefaultsModuleBase) properties() []interface{} {
165	return d.defaultableProperties
166}
167
168func (d *DefaultsModuleBase) productVariableProperties() interface{} {
169	return d.defaultableVariableProperties
170}
171
172func (d *DefaultsModuleBase) GenerateAndroidBuildActions(ctx ModuleContext) {}
173
174func InitDefaultsModule(module DefaultsModule) {
175	commonProperties := &commonProperties{}
176
177	module.AddProperties(
178		&hostAndDeviceProperties{},
179		commonProperties,
180		&ApexProperties{},
181		&distProperties{})
182
183	initAndroidModuleBase(module)
184	initProductVariableModule(module)
185	initArchModule(module)
186	InitDefaultableModule(module)
187
188	// Add properties that will not have defaults applied to them.
189	base := module.base()
190	defaultsVisibility := &DefaultsVisibilityProperties{}
191	module.AddProperties(&base.nameProperties, defaultsVisibility)
192
193	// Unlike non-defaults modules the visibility property is not stored in m.base().commonProperties.
194	// Instead it is stored in a separate instance of commonProperties created above so clear the
195	// existing list of properties.
196	clearVisibilityProperties(module)
197
198	// The defaults_visibility property controls the visibility of a defaults module so it must be
199	// set as the primary property, which also adds it to the list.
200	setPrimaryVisibilityProperty(module, "defaults_visibility", &defaultsVisibility.Defaults_visibility)
201
202	// The visibility property needs to be checked (but not parsed) by the visibility module during
203	// its checking phase and parsing phase so add it to the list as a normal property.
204	AddVisibilityProperty(module, "visibility", &commonProperties.Visibility)
205
206	// The applicable licenses property for defaults is 'licenses'.
207	setPrimaryLicensesProperty(module, "licenses", &commonProperties.Licenses)
208}
209
210var _ Defaults = (*DefaultsModuleBase)(nil)
211
212func (defaultable *DefaultableModuleBase) applyDefaults(ctx TopDownMutatorContext,
213	defaultsList []Defaults) {
214
215	for _, defaults := range defaultsList {
216		for _, prop := range defaultable.defaultableProperties {
217			if prop == defaultable.defaultableVariableProperties {
218				defaultable.applyDefaultVariableProperties(ctx, defaults, prop)
219			} else {
220				defaultable.applyDefaultProperties(ctx, defaults, prop)
221			}
222		}
223	}
224}
225
226// Product variable properties need special handling, the type of the filtered product variable
227// property struct may not be identical between the defaults module and the defaultable module.
228// Use PrependMatchingProperties to apply whichever properties match.
229func (defaultable *DefaultableModuleBase) applyDefaultVariableProperties(ctx TopDownMutatorContext,
230	defaults Defaults, defaultableProp interface{}) {
231	if defaultableProp == nil {
232		return
233	}
234
235	defaultsProp := defaults.productVariableProperties()
236	if defaultsProp == nil {
237		return
238	}
239
240	dst := []interface{}{
241		defaultableProp,
242		// Put an empty copy of the src properties into dst so that properties in src that are not in dst
243		// don't cause a "failed to find property to extend" error.
244		proptools.CloneEmptyProperties(reflect.ValueOf(defaultsProp)).Interface(),
245	}
246
247	err := proptools.PrependMatchingProperties(dst, defaultsProp, nil)
248	if err != nil {
249		if propertyErr, ok := err.(*proptools.ExtendPropertyError); ok {
250			ctx.PropertyErrorf(propertyErr.Property, "%s", propertyErr.Err.Error())
251		} else {
252			panic(err)
253		}
254	}
255}
256
257func (defaultable *DefaultableModuleBase) applyDefaultProperties(ctx TopDownMutatorContext,
258	defaults Defaults, defaultableProp interface{}) {
259
260	for _, def := range defaults.properties() {
261		if proptools.TypeEqual(defaultableProp, def) {
262			err := proptools.PrependProperties(defaultableProp, def, nil)
263			if err != nil {
264				if propertyErr, ok := err.(*proptools.ExtendPropertyError); ok {
265					ctx.PropertyErrorf(propertyErr.Property, "%s", propertyErr.Err.Error())
266				} else {
267					panic(err)
268				}
269			}
270		}
271	}
272}
273
274func RegisterDefaultsPreArchMutators(ctx RegisterMutatorsContext) {
275	ctx.BottomUp("defaults_deps", defaultsDepsMutator).Parallel()
276	ctx.TopDown("defaults", defaultsMutator).Parallel()
277}
278
279func defaultsDepsMutator(ctx BottomUpMutatorContext) {
280	if defaultable, ok := ctx.Module().(Defaultable); ok {
281		ctx.AddDependency(ctx.Module(), DefaultsDepTag, defaultable.defaults().Defaults...)
282	}
283}
284
285func defaultsMutator(ctx TopDownMutatorContext) {
286	if defaultable, ok := ctx.Module().(Defaultable); ok {
287		if len(defaultable.defaults().Defaults) > 0 {
288			var defaultsList []Defaults
289			seen := make(map[Defaults]bool)
290
291			ctx.WalkDeps(func(module, parent Module) bool {
292				if ctx.OtherModuleDependencyTag(module) == DefaultsDepTag {
293					if defaults, ok := module.(Defaults); ok {
294						if !seen[defaults] {
295							seen[defaults] = true
296							defaultsList = append(defaultsList, defaults)
297							return len(defaults.defaults().Defaults) > 0
298						}
299					} else {
300						ctx.PropertyErrorf("defaults", "module %s is not an defaults module",
301							ctx.OtherModuleName(module))
302					}
303				}
304				return false
305			})
306			defaultable.applyDefaults(ctx, defaultsList)
307		}
308
309		defaultable.CallHookIfAvailable(ctx)
310	}
311}
312