Select statements

See the blueprint cl for more information.

Things still to do:
 - Support selecting on product variables and
   variants
 - Test/Support property struct reflection tags
   like arch_variant, path, and variant_prepend
 - Test that selects combine well with existing
   configurability mechanisms like arch:, target:,
   multilib:, python's version:, etc.

Bug: 323382414
Test: go tests
Change-Id: If5d1ea1ad0c4ebabffaea91d62e1a1c6f926a793

1 files changed, 34 insertions, 0 deletions

diff --git a/android/module_context.go b/android/module_context.go
index 1cab63022..3fc5d0158 100644
--- a/android/module_context.go
+++ b/android/module_context.go
@@ -21,6 +21,7 @@ import (
 	"strings"
 
 	"github.com/google/blueprint"
+	"github.com/google/blueprint/parser"
 	"github.com/google/blueprint/proptools"
 )
 
@@ -212,6 +213,10 @@ type ModuleContext interface {
 	// GenerateAndroidBuildActions.  If it is called then the struct will be written out and included in
 	// the module-info.json generated by Make, and Make will not generate its own data for this module.
 	ModuleInfoJSON() *ModuleInfoJSON
+
+	// EvaluateConfiguration makes ModuleContext a valid proptools.ConfigurableEvaluator, so this context
+	// can be used to evaluate the final value of Configurable properties.
+	EvaluateConfiguration(parser.SelectType, string) (string, bool)
 }
 
 type moduleContext struct {
@@ -714,3 +719,32 @@ func (m *moduleContext) HostRequiredModuleNames() []string {
 func (m *moduleContext) TargetRequiredModuleNames() []string {
 	return m.module.TargetRequiredModuleNames()
 }
+
+func (m *moduleContext) EvaluateConfiguration(ty parser.SelectType, condition string) (string, bool) {
+	switch ty {
+	case parser.SelectTypeReleaseVariable:
+		if v, ok := m.Config().productVariables.BuildFlags[condition]; ok {
+			return v, true
+		}
+		return "", false
+	case parser.SelectTypeProductVariable:
+		// TODO: Might add these on a case-by-case basis
+		m.ModuleErrorf("TODO(b/323382414): Product variables are not yet supported in selects")
+		return "", false
+	case parser.SelectTypeSoongConfigVariable:
+		parts := strings.Split(condition, ":")
+		namespace := parts[0]
+		variable := parts[1]
+		if n, ok := m.Config().productVariables.VendorVars[namespace]; ok {
+			if v, ok := n[variable]; ok {
+				return v, true
+			}
+		}
+		return "", false
+	case parser.SelectTypeVariant:
+		m.ModuleErrorf("TODO(b/323382414): Variants are not yet supported in selects")
+		return "", false
+	default:
+		panic("Should be unreachable")
+	}
+}