Optimize filterArchStruct when nothing is filtered

Runtime-created struct types have limit on the name of the type,
which is the full text of the fields in the struct.  Avoid creating
runtime struct types when filtering produces an identical struct.
Also add tests and godoc for filterArchStruct.

Test: arch_test.go
Change-Id: If7eb27ea9e72073d5252e93f2110b08889ed76b1

1 files changed, 232 insertions, 0 deletions

diff --git a/android/arch_test.go b/android/arch_test.go
new file mode 100644
index 000000000..0589e6c3a
--- /dev/null
+++ b/android/arch_test.go
@@ -0,0 +1,232 @@
+// Copyright 2019 Google Inc. All rights reserved.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package android
+
+import (
+	"reflect"
+	"testing"
+)
+
+type Named struct {
+	A *string `android:"arch_variant"`
+	B *string
+}
+
+type NamedAllFiltered struct {
+	A *string
+}
+
+type NamedNoneFiltered struct {
+	A *string `android:"arch_variant"`
+}
+
+func TestFilterArchStruct(t *testing.T) {
+	tests := []struct {
+		name     string
+		in       interface{}
+		out      interface{}
+		filtered bool
+	}{
+		// Property tests
+		{
+			name: "basic",
+			in: &struct {
+				A *string `android:"arch_variant"`
+				B *string
+			}{},
+			out: &struct {
+				A *string
+			}{},
+			filtered: true,
+		},
+		{
+			name: "all filtered",
+			in: &struct {
+				A *string
+			}{},
+			out:      nil,
+			filtered: true,
+		},
+		{
+			name: "none filtered",
+			in: &struct {
+				A *string `android:"arch_variant"`
+			}{},
+			out: &struct {
+				A *string `android:"arch_variant"`
+			}{},
+			filtered: false,
+		},
+
+		// Sub-struct tests
+		{
+			name: "substruct",
+			in: &struct {
+				A struct {
+					A *string `android:"arch_variant"`
+					B *string
+				} `android:"arch_variant"`
+			}{},
+			out: &struct {
+				A struct {
+					A *string
+				}
+			}{},
+			filtered: true,
+		},
+		{
+			name: "substruct all filtered",
+			in: &struct {
+				A struct {
+					A *string
+				} `android:"arch_variant"`
+			}{},
+			out:      nil,
+			filtered: true,
+		},
+		{
+			name: "substruct none filtered",
+			in: &struct {
+				A struct {
+					A *string `android:"arch_variant"`
+				} `android:"arch_variant"`
+			}{},
+			out: &struct {
+				A struct {
+					A *string `android:"arch_variant"`
+				} `android:"arch_variant"`
+			}{},
+			filtered: false,
+		},
+
+		// Named sub-struct tests
+		{
+			name: "named substruct",
+			in: &struct {
+				A Named `android:"arch_variant"`
+			}{},
+			out: &struct {
+				A struct {
+					A *string
+				}
+			}{},
+			filtered: true,
+		},
+		{
+			name: "substruct all filtered",
+			in: &struct {
+				A NamedAllFiltered `android:"arch_variant"`
+			}{},
+			out:      nil,
+			filtered: true,
+		},
+		{
+			name: "substruct none filtered",
+			in: &struct {
+				A NamedNoneFiltered `android:"arch_variant"`
+			}{},
+			out: &struct {
+				A NamedNoneFiltered `android:"arch_variant"`
+			}{},
+			filtered: false,
+		},
+
+		// Pointer to sub-struct tests
+		{
+			name: "pointer substruct",
+			in: &struct {
+				A *struct {
+					A *string `android:"arch_variant"`
+					B *string
+				} `android:"arch_variant"`
+			}{},
+			out: &struct {
+				A *struct {
+					A *string
+				}
+			}{},
+			filtered: true,
+		},
+		{
+			name: "pointer substruct all filtered",
+			in: &struct {
+				A *struct {
+					A *string
+				} `android:"arch_variant"`
+			}{},
+			out:      nil,
+			filtered: true,
+		},
+		{
+			name: "pointer substruct none filtered",
+			in: &struct {
+				A *struct {
+					A *string `android:"arch_variant"`
+				} `android:"arch_variant"`
+			}{},
+			out: &struct {
+				A *struct {
+					A *string `android:"arch_variant"`
+				} `android:"arch_variant"`
+			}{},
+			filtered: false,
+		},
+
+		// Pointer to named sub-struct tests
+		{
+			name: "pointer named substruct",
+			in: &struct {
+				A *Named `android:"arch_variant"`
+			}{},
+			out: &struct {
+				A *struct {
+					A *string
+				}
+			}{},
+			filtered: true,
+		},
+		{
+			name: "pointer substruct all filtered",
+			in: &struct {
+				A *NamedAllFiltered `android:"arch_variant"`
+			}{},
+			out:      nil,
+			filtered: true,
+		},
+		{
+			name: "pointer substruct none filtered",
+			in: &struct {
+				A *NamedNoneFiltered `android:"arch_variant"`
+			}{},
+			out: &struct {
+				A *NamedNoneFiltered `android:"arch_variant"`
+			}{},
+			filtered: false,
+		},
+	}
+
+	for _, test := range tests {
+		t.Run(test.name, func(t *testing.T) {
+			out, filtered := filterArchStruct(reflect.TypeOf(test.in))
+			if filtered != test.filtered {
+				t.Errorf("expected filtered %v, got %v", test.filtered, filtered)
+			}
+			expected := reflect.TypeOf(test.out)
+			if out != expected {
+				t.Errorf("expected type %v, got %v", expected, out)
+			}
+		})
+	}
+}