support sandboxed rust rules

This commit adds support for compiling rust rules inside the sbox
sandbox. To compile a rust module with sandboxing enabled, the entry
point to the crate must be specified via the `crate_root` property, and
all input sources and compile-time data must be specified via the `srcs`
and `compile_data` properties.

Bug: 286077158
Change-Id: I8c9dc5cf7578037a583b4be2e2f73cf20ffd4408

rust/compiler.go

@@ -82,6 +82,9 @@ type BaseCompilerProperties struct {
 	//          not directly used as source files.
 	Crate_root *string `android:"path,arch_variant"`
 
+	// Additional data files that are used during compilation only. These are not accessible at runtime.
+	Compile_data []string `android:"path,arch_variant"`
+
 	// name of the lint set that should be used to validate this module.
 	//
 	// Possible values are "default" (for using a sensible set of lints
@@ -343,6 +346,23 @@ func (compiler *baseCompiler) compile(ctx ModuleContext, flags Flags, deps PathD
 	panic(fmt.Errorf("baseCrater doesn't know how to crate things!"))
 }
 
+func (compile *baseCompiler) crateRoot(ctx ModuleContext) android.Path {
+	if compile.Properties.Crate_root != nil {
+		return android.PathForModuleSrc(ctx, *compile.Properties.Crate_root)
+	}
+	return nil
+}
+
+// compilationSourcesAndData returns a list of files necessary to complete the compilation.
+// This includes the rust source files as well as any other data files that
+// are referenced during the build.
+func (compile *baseCompiler) compilationSourcesAndData(ctx ModuleContext) android.Paths {
+	return android.PathsForModuleSrc(ctx, android.Concat(
+		compile.Properties.Srcs,
+		compile.Properties.Compile_data,
+	))
+}
+
 func (compiler *baseCompiler) rustdoc(ctx ModuleContext, flags Flags,
 	deps PathDeps) android.OptionalPath {