Add a function to create config_setting(s)

The use case for this is creating config_setting(s) specific to an apex
variant and selecting stub/impl in that config_setting. We likely need
only a handful of such config_setting(s), but determining that list
requires iterating the build graph.

Test: go test ./bp2build
Change-Id: I9aa552e3d0bcf67513023c3a7d4bbf8fae464ee4
diff --git a/bp2build/build_conversion.go b/bp2build/build_conversion.go
index b7678a4..a860484 100644
--- a/bp2build/build_conversion.go
+++ b/bp2build/build_conversion.go
@@ -600,6 +600,11 @@
 		// TODO(b/164227191): implement pretty print for interfaces.
 		// Interfaces are used for for arch, multilib and target properties.
 		return "", nil
+	case reflect.Map:
+		if v, ok := propertyValue.Interface().(bazel.StringMapAttribute); ok {
+			return starlark_fmt.PrintStringStringDict(v, indent), nil
+		}
+		return "", fmt.Errorf("bp2build expects map of type map[string]string for field: %s", propertyValue)
 	default:
 		return "", fmt.Errorf(
 			"unexpected kind for property struct field: %s", propertyValue.Kind())
diff --git a/bp2build/build_conversion_test.go b/bp2build/build_conversion_test.go
index 73ee26b..1b64055 100644
--- a/bp2build/build_conversion_test.go
+++ b/bp2build/build_conversion_test.go
@@ -1898,3 +1898,36 @@
 		Description:          "Generating API contribution Bazel targets for custom module",
 	})
 }
+
+func TestGenerateConfigSetting(t *testing.T) {
+	bp := `
+	custom {
+		name: "foo",
+		test_config_setting: true,
+	}
+	`
+	expectedBazelTargets := []string{
+		MakeBazelTargetNoRestrictions(
+			"config_setting",
+			"foo_config_setting",
+			AttrNameToString{
+				"flag_values": `{
+        "//build/bazel/rules/my_string_setting": "foo",
+    }`,
+			},
+		),
+		MakeBazelTarget(
+			"custom",
+			"foo",
+			AttrNameToString{},
+		),
+	}
+	registerCustomModule := func(ctx android.RegistrationContext) {
+		ctx.RegisterModuleType("custom", customModuleFactoryHostAndDevice)
+	}
+	RunBp2BuildTestCase(t, registerCustomModule, Bp2buildTestCase{
+		Blueprint:            bp,
+		ExpectedBazelTargets: expectedBazelTargets,
+		Description:          "Generating API contribution Bazel targets for custom module",
+	})
+}
diff --git a/bp2build/bzl_conversion_test.go b/bp2build/bzl_conversion_test.go
index a8e557d..fa1bf8a 100644
--- a/bp2build/bzl_conversion_test.go
+++ b/bp2build/bzl_conversion_test.go
@@ -108,6 +108,7 @@
         "string_literal_prop": attr.string(),
         "string_prop": attr.string(),
         "string_ptr_prop": attr.string(),
+        "test_config_setting": attr.bool(),
     },
 )
 
@@ -139,6 +140,7 @@
         "string_literal_prop": attr.string(),
         "string_prop": attr.string(),
         "string_ptr_prop": attr.string(),
+        "test_config_setting": attr.bool(),
     },
 )
 
@@ -170,6 +172,7 @@
         "string_literal_prop": attr.string(),
         "string_prop": attr.string(),
         "string_ptr_prop": attr.string(),
+        "test_config_setting": attr.bool(),
         # test_prop start
 #         "test_string_prop": attr.string(),
         # test_prop end
diff --git a/bp2build/testing.go b/bp2build/testing.go
index 6e919db..fd99ff0 100644
--- a/bp2build/testing.go
+++ b/bp2build/testing.go
@@ -317,6 +317,8 @@
 	One_to_many_prop *bool
 
 	Api *string // File describing the APIs of this module
+
+	Test_config_setting *bool // Used to test generation of config_setting targets
 }
 
 type customModule struct {
@@ -490,6 +492,27 @@
 	}
 
 	ctx.CreateBazelTargetModule(props, android.CommonAttributes{Name: m.Name()}, attrs)
+
+	if proptools.Bool(m.props.Test_config_setting) {
+		m.createConfigSetting(ctx)
+	}
+
+}
+
+func (m *customModule) createConfigSetting(ctx android.TopDownMutatorContext) {
+	csa := bazel.ConfigSettingAttributes{
+		Flag_values: bazel.StringMapAttribute{
+			"//build/bazel/rules/my_string_setting": m.Name(),
+		},
+	}
+	ca := android.CommonAttributes{
+		Name: m.Name() + "_config_setting",
+	}
+	ctx.CreateBazelConfigSetting(
+		csa,
+		ca,
+		ctx.ModuleDir(),
+	)
 }
 
 var _ android.ApiProvider = (*customModule)(nil)