diff options
Diffstat (limited to 'android/deapexer.go')
| -rw-r--r-- | android/deapexer.go | 81 |
1 files changed, 64 insertions, 17 deletions
diff --git a/android/deapexer.go b/android/deapexer.go index 63508d78b..f3c541c17 100644 --- a/android/deapexer.go +++ b/android/deapexer.go @@ -15,31 +15,67 @@ package android import ( - "fmt" - "strings" - "github.com/google/blueprint" ) // Provides support for interacting with the `deapexer` module to which a `prebuilt_apex` module // will delegate the work to export files from a prebuilt '.apex` file. +// +// The actual processing that is done is quite convoluted but it is all about combining information +// from multiple different sources in order to allow a prebuilt module to use a file extracted from +// an apex file. As follows: +// +// 1. A prebuilt module, e.g. prebuilt_bootclasspath_fragment or java_import needs to use a file +// from a prebuilt_apex/apex_set. It knows the path of the file within the apex but does not know +// where the apex file is or what apex to use. +// +// 2. The connection between the prebuilt module and the prebuilt_apex/apex_set is created through +// use of an exported_... property on the latter. That causes four things to occur: +// a. A `deapexer` mopdule is created by the prebuilt_apex/apex_set to extract files from the +// apex file. +// b. A dependency is added from the prebuilt_apex/apex_set modules onto the prebuilt modules +// listed in those properties. +// c. An APEX variant is created for each of those prebuilt modules. +// d. A dependency is added from the prebuilt modules to the `deapexer` module. +// +// 3. The prebuilt_apex/apex_set modules do not know which files are available in the apex file. +// That information could be specified on the prebuilt_apex/apex_set modules but without +// automated generation of those modules it would be expensive to maintain. So, instead they +// obtain that information from the prebuilt modules. They do not know what files are actually in +// the apex file either but they know what files they need from it. So, the +// prebuilt_apex/apex_set modules obtain the files that should be in the apex file from those +// modules and then pass those onto the `deapexer` module. +// +// 4. The `deapexer` module's ninja rule extracts all the files from the apex file into an output +// directory and checks that all the expected files are there. The expected files are declared as +// the outputs of the ninja rule so they are available to other modules. +// +// 5. The prebuilt modules then retrieve the paths to the files that they needed from the `deapexer` +// module. +// +// The files that are passed to `deapexer` and those that are passed back have a unique identifier +// that links them together. e.g. If the `deapexer` is passed something like this: +// core-libart{.dexjar} -> javalib/core-libart.jar +// it will return something like this: +// core-libart{.dexjar} -> out/soong/.....deapexer.../javalib/core-libart.jar +// +// The reason why the `deapexer` module is separate from the prebuilt_apex/apex_set is to avoid +// cycles. e.g. +// prebuilt_apex "com.android.art" depends upon java_import "core-libart": +// This is so it can create an APEX variant of the latter and obtain information about the +// files that it needs from the apex file. +// java_import "core-libart" depends upon `deapexer` module: +// This is so it can retrieve the paths to the files it needs. // The information exported by the `deapexer` module, access it using `DeapxerInfoProvider`. type DeapexerInfo struct { // map from the name of an exported file from a prebuilt_apex to the path to that file. The - // exported file name is of the form <module>{<tag>} where <tag> is currently only allowed to be - // ".dexjar". + // exported file name is of the form <module>{<tag>}. // // See Prebuilt.ApexInfoMutator for more information. exports map[string]Path } -// The set of supported prebuilt export tags. Used to verify the tag parameter for -// `PrebuiltExportPath`. -var supportedPrebuiltExportTags = map[string]struct{}{ - ".dexjar": {}, -} - // PrebuiltExportPath provides the path, or nil if not available, of a file exported from the // prebuilt_apex that created this ApexInfo. // @@ -51,12 +87,6 @@ var supportedPrebuiltExportTags = map[string]struct{}{ // // See apex/deapexer.go for more information. func (i DeapexerInfo) PrebuiltExportPath(name, tag string) Path { - - if _, ok := supportedPrebuiltExportTags[tag]; !ok { - panic(fmt.Errorf("unsupported prebuilt export tag %q, expected one of %s", - tag, strings.Join(SortedStringKeys(supportedPrebuiltExportTags), ", "))) - } - path := i.exports[name+"{"+tag+"}"] return path } @@ -79,5 +109,22 @@ type deapexerTagStruct struct { blueprint.BaseDependencyTag } +// Mark this tag so dependencies that use it are excluded from APEX contents. +func (t deapexerTagStruct) ExcludeFromApexContents() {} + +var _ ExcludeFromApexContentsTag = DeapexerTag + // A tag that is used for dependencies on the `deapexer` module. var DeapexerTag = deapexerTagStruct{} + +// RequiredFilesFromPrebuiltApex must be implemented by modules that require files to be exported +// from a prebuilt_apex/apex_set. +type RequiredFilesFromPrebuiltApex interface { + // RequiredFilesFromPrebuiltApex returns a map from the key (module name plus tag) to the required + // path of the file within the prebuilt .apex file. + // + // For each key/file pair this will cause the file to be extracted out of the prebuilt .apex file, + // and the path to the extracted file will be stored in the DeapexerInfo using that key, The path + // can then be retrieved using the PrebuiltExportPath(name, tag) method. + RequiredFilesFromPrebuiltApex(ctx BaseModuleContext) map[string]string +} |