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/*
* Copyright (C) 2021 The Android Open Source Project
*
* 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 java
import (
"fmt"
"strings"
"android/soong/android"
"github.com/google/blueprint"
)
// Supports constructing a list of ClasspathElement from a set of fragments and modules.
// ClasspathElement represents a component that contributes to a classpath. That can be
// either a java module or a classpath fragment module.
type ClasspathElement interface {
Module() android.Module
String() string
}
type ClasspathElements []ClasspathElement
// ClasspathFragmentElement is a ClasspathElement that encapsulates a classpath fragment module.
type ClasspathFragmentElement struct {
Fragment android.Module
Contents []android.Module
}
func (b *ClasspathFragmentElement) Module() android.Module {
return b.Fragment
}
func (b *ClasspathFragmentElement) String() string {
contents := []string{}
for _, module := range b.Contents {
contents = append(contents, module.String())
}
return fmt.Sprintf("fragment(%s, %s)", b.Fragment, strings.Join(contents, ", "))
}
var _ ClasspathElement = (*ClasspathFragmentElement)(nil)
// ClasspathLibraryElement is a ClasspathElement that encapsulates a java library.
type ClasspathLibraryElement struct {
Library android.Module
}
func (b *ClasspathLibraryElement) Module() android.Module {
return b.Library
}
func (b *ClasspathLibraryElement) String() string {
return fmt.Sprintf("library{%s}", b.Library)
}
var _ ClasspathElement = (*ClasspathLibraryElement)(nil)
// ClasspathElementContext defines the context methods needed by CreateClasspathElements
type ClasspathElementContext interface {
OtherModuleHasProvider(m blueprint.Module, provider blueprint.ProviderKey) bool
OtherModuleProvider(m blueprint.Module, provider blueprint.ProviderKey) interface{}
ModuleErrorf(fmt string, args ...interface{})
}
// CreateClasspathElements creates a list of ClasspathElement objects from a list of libraries and
// a list of fragments.
//
// The libraries parameter contains the set of libraries from which the classpath is constructed.
// The fragments parameter contains the classpath fragment modules whose contents are libraries that
// are part of the classpath. Each library in the libraries parameter may be part of a fragment. The
// determination as to which libraries belong to fragments and which do not is based on the apex to
// which they belong, if any.
//
// Every fragment in the fragments list must be part of one or more apexes and each apex is assumed
// to contain only a single fragment from the fragments list. A library in the libraries parameter
// that is part of an apex must be provided by a classpath fragment in the corresponding apex.
//
// This will return a ClasspathElements list that contains a ClasspathElement for each standalone
// library and each fragment. The order of the elements in the list is such that if the list was
// flattened into a list of library modules that it would result in the same list or modules as the
// input libraries. Flattening the list can be done by replacing each ClasspathFragmentElement in
// the list with its Contents field.
//
// Requirements/Assumptions:
// * A fragment can be associated with more than one apex but each apex must only be associated with
// a single fragment from the fragments list.
// * All of a fragment's contents must appear as a contiguous block in the same order in the
// libraries list.
// * Each library must only appear in a single fragment.
//
// The apex is used to identify which libraries belong to which fragment. First a mapping is created
// from apex to fragment. Then the libraries are iterated over and any library in an apex is
// associated with an element for the fragment to which it belongs. Otherwise, the libraries are
// standalone and have their own element.
//
// e.g. Given the following input:
// libraries: com.android.art:core-oj, com.android.art:core-libart, framework, ext
// fragments: com.android.art:art-bootclasspath-fragment
//
// Then this will return:
// ClasspathFragmentElement(art-bootclasspath-fragment, [core-oj, core-libart]),
// ClasspathLibraryElement(framework),
// ClasspathLibraryElement(ext),
func CreateClasspathElements(ctx ClasspathElementContext, libraries []android.Module, fragments []android.Module) ClasspathElements {
// Create a map from apex name to the fragment module. This makes it easy to find the fragment
// associated with a particular apex.
apexToFragment := map[string]android.Module{}
for _, fragment := range fragments {
if !ctx.OtherModuleHasProvider(fragment, android.ApexInfoProvider) {
ctx.ModuleErrorf("fragment %s is not part of an apex", fragment)
continue
}
apexInfo := ctx.OtherModuleProvider(fragment, android.ApexInfoProvider).(android.ApexInfo)
for _, apex := range apexInfo.InApexVariants {
if existing, ok := apexToFragment[apex]; ok {
ctx.ModuleErrorf("apex %s has multiple fragments, %s and %s", apex, fragment, existing)
continue
}
apexToFragment[apex] = fragment
}
}
fragmentToElement := map[android.Module]*ClasspathFragmentElement{}
elements := []ClasspathElement{}
var currentElement ClasspathElement
skipLibrary:
// Iterate over the libraries to construct the ClasspathElements list.
for _, library := range libraries {
var element ClasspathElement
if ctx.OtherModuleHasProvider(library, android.ApexInfoProvider) {
apexInfo := ctx.OtherModuleProvider(library, android.ApexInfoProvider).(android.ApexInfo)
var fragment android.Module
// Make sure that the library is in only one fragment of the classpath.
for _, apex := range apexInfo.InApexVariants {
if f, ok := apexToFragment[apex]; ok {
if fragment == nil {
// This is the first fragment so just save it away.
fragment = f
} else if f != fragment {
// This apex variant of the library is in a different fragment.
ctx.ModuleErrorf("library %s is in two separate fragments, %s and %s", library, fragment, f)
// Skip over this library entirely as otherwise the resulting classpath elements would
// be invalid.
continue skipLibrary
}
} else {
// There is no fragment associated with the library's apex.
}
}
if fragment == nil {
ctx.ModuleErrorf("library %s is from apexes %s which have no corresponding fragment in %s",
library, apexInfo.InApexVariants, fragments)
// Skip over this library entirely as otherwise the resulting classpath elements would
// be invalid.
continue skipLibrary
} else if existingFragmentElement, ok := fragmentToElement[fragment]; ok {
// This library is in a fragment element that has already been added.
// If the existing fragment element is still the current element then this library is
// contiguous with other libraries in that fragment so there is nothing more to do.
// Otherwise this library is not contiguous with other libraries in the same fragment which
// is an error.
if existingFragmentElement != currentElement {
separator := ""
if fragmentElement, ok := currentElement.(*ClasspathFragmentElement); ok {
separator = fmt.Sprintf("libraries from fragment %s like %s", fragmentElement.Fragment, fragmentElement.Contents[0])
} else {
libraryElement := currentElement.(*ClasspathLibraryElement)
separator = fmt.Sprintf("library %s", libraryElement.Library)
}
// Get the library that precedes this library in the fragment. That is the last library as
// this library has not yet been added.
precedingLibraryInFragment := existingFragmentElement.Contents[len(existingFragmentElement.Contents)-1]
ctx.ModuleErrorf("libraries from the same fragment must be contiguous, however %s and %s from fragment %s are separated by %s",
precedingLibraryInFragment, library, fragment, separator)
}
// Add this library to the fragment element's contents.
existingFragmentElement.Contents = append(existingFragmentElement.Contents, library)
} else {
// This is the first library in this fragment so add a new element for the fragment,
// including the library.
fragmentElement := &ClasspathFragmentElement{
Fragment: fragment,
Contents: []android.Module{library},
}
// Store it away so we can detect when attempting to create another element for the same
// fragment.
fragmentToElement[fragment] = fragmentElement
element = fragmentElement
}
} else {
// The library is from the platform so just add an element for it.
element = &ClasspathLibraryElement{Library: library}
}
// If no element was created then it means that the library has been added to an existing
// fragment element so the list of elements and current element are unaffected.
if element != nil {
// Add the element to the list and make it the current element for the next iteration.
elements = append(elements, element)
currentElement = element
}
}
return elements
}