Allow implementation details to be excluded from signature patterns file
Previously, the signature-patterns.csv file (which was output in an sdk
snapshot) included implementation details, e.g. the names of classes
that are not part of any API, including the hidden API. This change
allows a bootclasspath_fragment module owner to customize the generated
signature patterns file to remove as many implementation details as
possible from the sdk snapshot. That means that implementation only
changes would not require that sdk snapshots be updated in sync with
the corresponding APEX.
Module owners can remove implementation in the following ways:
1) Limit the number of packages that are treated as split packages by
explicitly specifying the split packages in the split_packages
property. A split package is one whose classes are provided by
separate bootclasspath_fragment modules and so the signature
patterns has to include every class in that package provided by a
specific bootclasspath_fragment module, including implementation
classes, instead of just listing the package.
The default is to treat all packages as being split, so if no
split_packages is specified then it defaults to ["*"] which matches
all packages. Assuming that no package was split unless specifically
stated would require that all the modules that had split packages
explicitly list them before this change could be submitted as
without them this change would break the build.
Once all existing modules with split packages have been updated to
include them then the default may be changed.
2) Adding package prefixes for any hierarchy of packages that are
owned solely by that bootclasspath_fragment. This removes the need
to list the packages in that hierarchy, including implementation
specific packages.
Bug: 194063708
Test: atest --host verify_overlaps_test signature_patterns_test
m out/soong/hiddenapi/hiddenapi-flags.csv
- manually change files to cause difference in flags to check
that it detects the differences.
Change-Id: If2f90cfc41b6fff9fa4ac8b9d4973110938b9392
diff --git a/java/bootclasspath_fragment.go b/java/bootclasspath_fragment.go
index ced0048..8f18790 100644
--- a/java/bootclasspath_fragment.go
+++ b/java/bootclasspath_fragment.go
@@ -139,6 +139,74 @@
BootclasspathFragmentsDepsProperties
}
+type SourceOnlyBootclasspathProperties struct {
+ Hidden_api struct {
+ // Contains prefixes of a package hierarchy that is provided solely by this
+ // bootclasspath_fragment.
+ //
+ // This affects the signature patterns file that is used to select the subset of monolithic
+ // hidden API flags. See split_packages property for more details.
+ Package_prefixes []string
+
+ // The list of split packages provided by this bootclasspath_fragment.
+ //
+ // A split package is one that contains classes which are provided by multiple
+ // bootclasspath_fragment modules.
+ //
+ // This defaults to "*" - which treats all packages as being split. A module that has no split
+ // packages must specify an empty list.
+ //
+ // This affects the signature patterns file that is generated by a bootclasspath_fragment and
+ // used to select the subset of monolithic hidden API flags against which the flags generated
+ // by the bootclasspath_fragment are compared.
+ //
+ // The signature patterns file selects the subset of monolithic hidden API flags using a number
+ // of patterns, i.e.:
+ // * The qualified name (including package) of an outermost class, e.g. java/lang/Character.
+ // This selects all the flags for all the members of this class and any nested classes.
+ // * A package wildcard, e.g. java/lang/*. This selects all the flags for all the members of all
+ // the classes in this package (but not in sub-packages).
+ // * A recursive package wildcard, e.g. java/**. This selects all the flags for all the members
+ // of all the classes in this package and sub-packages.
+ //
+ // The signature patterns file is constructed as follows:
+ // * All the signatures are retrieved from the all-flags.csv file.
+ // * The member and inner class names are removed.
+ // * If a class is in a split package then that is kept, otherwise the class part is removed
+ // and replaced with a wildcard, i.e. *.
+ // * If a package matches a package prefix then the package is removed.
+ // * All the package prefixes are added with a recursive wildcard appended to each, i.e. **.
+ // * The resulting patterns are sorted.
+ //
+ // So, by default (i.e. without specifying any package_prefixes or split_packages) the signature
+ // patterns is a list of class names, because there are no package packages and all packages are
+ // assumed to be split.
+ //
+ // If any split packages are specified then only those packages are treated as split and all
+ // other packages are treated as belonging solely to the bootclasspath_fragment and so they use
+ // wildcard package patterns.
+ //
+ // So, if an empty list of split packages is specified then the signature patterns file just
+ // includes a wildcard package pattern for every package provided by the bootclasspath_fragment.
+ //
+ // If split_packages are specified and a package that is split is not listed then it could lead
+ // to build failures as it will select monolithic flags that are generated by another
+ // bootclasspath_fragment to compare against the flags provided by this fragment. The latter
+ // will obviously not contain those flags and that can cause the comparison and build to fail.
+ //
+ // If any package prefixes are specified then any matching packages are removed from the
+ // signature patterns and replaced with a single recursive package pattern.
+ //
+ // It is not strictly necessary to specify either package_prefixes or split_packages as the
+ // defaults will produce a valid set of signature patterns. However, those patterns may include
+ // implementation details, e.g. names of implementation classes or packages, which will be
+ // exported to the sdk snapshot in the signature patterns file. That is something that should be
+ // avoided where possible. Specifying package_prefixes and split_packages allows those
+ // implementation details to be excluded from the snapshot.
+ Split_packages []string
+ }
+}
+
type BootclasspathFragmentModule struct {
android.ModuleBase
android.ApexModuleBase
@@ -147,6 +215,8 @@
properties bootclasspathFragmentProperties
+ sourceOnlyProperties SourceOnlyBootclasspathProperties
+
// Collect the module directory for IDE info in java/jdeps.go.
modulePaths []string
}
@@ -180,7 +250,7 @@
func bootclasspathFragmentFactory() android.Module {
m := &BootclasspathFragmentModule{}
- m.AddProperties(&m.properties)
+ m.AddProperties(&m.properties, &m.sourceOnlyProperties)
android.InitApexModule(m)
android.InitSdkAwareModule(m)
initClasspathFragment(m, BOOTCLASSPATH)
@@ -590,7 +660,7 @@
// TODO(b/192868581): Remove once the source and prebuilts provide a signature patterns file of
// their own.
if output.SignaturePatternsPath == nil {
- output.SignaturePatternsPath = buildRuleSignaturePatternsFile(ctx, output.AllFlagsPath)
+ output.SignaturePatternsPath = buildRuleSignaturePatternsFile(ctx, output.AllFlagsPath, []string{"*"}, nil)
}
// Initialize a HiddenAPIInfo structure.
@@ -659,7 +729,20 @@
func (b *BootclasspathFragmentModule) produceHiddenAPIOutput(ctx android.ModuleContext, contents []android.Module, input HiddenAPIFlagInput) *HiddenAPIOutput {
// Generate the rules to create the hidden API flags and update the supplied hiddenAPIInfo with the
// paths to the created files.
- return hiddenAPIRulesForBootclasspathFragment(ctx, contents, input)
+ output := hiddenAPIRulesForBootclasspathFragment(ctx, contents, input)
+
+ // If the module specifies split_packages or package_prefixes then use those to generate the
+ // signature patterns.
+ splitPackages := b.sourceOnlyProperties.Hidden_api.Split_packages
+ packagePrefixes := b.sourceOnlyProperties.Hidden_api.Package_prefixes
+ if splitPackages != nil || packagePrefixes != nil {
+ if splitPackages == nil {
+ splitPackages = []string{"*"}
+ }
+ output.SignaturePatternsPath = buildRuleSignaturePatternsFile(ctx, output.AllFlagsPath, splitPackages, packagePrefixes)
+ }
+
+ return output
}
// produceBootImageFiles builds the boot image files from the source if it is required.