Add documentation for the different files created by hiddenapi
Test: m nothing
Bug: 178361284
Change-Id: Id55646b9d4b7bc1acdb4ed6a6dd4456b746eb54c
diff --git a/java/hiddenapi_singleton.go b/java/hiddenapi_singleton.go
index 4bd255c..ccb8745 100644
--- a/java/hiddenapi_singleton.go
+++ b/java/hiddenapi_singleton.go
@@ -28,9 +28,64 @@
}
type hiddenAPISingletonPathsStruct struct {
- flags android.OutputPath
- index android.OutputPath
- metadata android.OutputPath
+ // The path to the CSV file that contains the flags that will be encoded into the dex boot jars.
+ //
+ // It is created by the generate_hiddenapi_lists.py tool that is passed the stubFlags along with
+ // a number of additional files that are used to augment the information in the stubFlags with
+ // manually curated data.
+ flags android.OutputPath
+
+ // The path to the CSV index file that contains mappings from Java signature to source location
+ // information for all Java elements annotated with the UnsupportedAppUsage annotation in the
+ // source of all the boot jars.
+ //
+ // It is created by the merge_csv tool which merges all the hiddenAPI.indexCSVPath files that have
+ // been created by the rest of the build. That includes the index files generated for
+ // <x>-hiddenapi modules.
+ index android.OutputPath
+
+ // The path to the CSV metadata file that contains mappings from Java signature to the value of
+ // properties specified on UnsupportedAppUsage annotations in the source of all the boot jars.
+ //
+ // It is created by the merge_csv tool which merges all the hiddenAPI.metadataCSVPath files that
+ // have been created by the rest of the build. That includes the metadata files generated for
+ // <x>-hiddenapi modules.
+ metadata android.OutputPath
+
+ // The path to the CSV metadata file that contains mappings from Java signature to flags obtained
+ // from the public, system and test API stubs.
+ //
+ // This is created by the hiddenapi tool which is given dex files for the public, system and test
+ // API stubs (including product specific stubs) along with dex boot jars, so does not include
+ // <x>-hiddenapi modules. For each API surface (i.e. public, system, test) it records which
+ // members in the dex boot jars match a member in the dex stub jars for that API surface and then
+ // outputs a file containing the signatures of all members in the dex boot jars along with the
+ // flags that indicate which API surface it belongs, if any.
+ //
+ // e.g. a dex member that matches a member in the public dex stubs would have flags
+ // "public-api,system-api,test-api" set (as system and test are both supersets of public). A dex
+ // member that didn't match a member in any of the dex stubs is still output it just has an empty
+ // set of flags.
+ //
+ // The notion of matching is quite complex, it is not restricted to just exact matching but also
+ // follows the Java inheritance rules. e.g. if a method is public then all overriding/implementing
+ // methods are also public. If an interface method is public and a class inherits an
+ // implementation of that method from a super class then that super class method is also public.
+ // That ensures that any method that can be called directly by an App through a public method is
+ // visible to that App.
+ //
+ // Propagating the visibility of members across the inheritance hierarchy at build time will cause
+ // problems when modularizing and unbundling as it that propagation can cross module boundaries.
+ // e.g. Say that a private framework class implements a public interface and inherits an
+ // implementation of one of its methods from a core platform ART class. In that case the ART
+ // implementation method needs to be marked as public which requires the build to have access to
+ // the framework implementation classes at build time. The work to rectify this is being tracked
+ // at http://b/178693149.
+ //
+ // This file (or at least those items marked as being in the public-api) is used by hiddenapi when
+ // creating the metadata and flags for the individual modules in order to perform consistency
+ // checks and filter out bridge methods that are part of the public API. The latter relies on the
+ // propagation of visibility across the inheritance hierarchy.
stubFlags android.OutputPath
}