Add infrastructure to support PythonBinary

Add a new request type with its own StarLark function
Hook it up via GetPythonBinary
Add to MockBazelContext a LabelToPythonBinary
Add a test for the new request type

Test: request_type_test.go:TestGetPythonBinaryParseResults
Change-Id: I05f6506adfbbdac8b3f40475509ed02ab8e844e5

android/bazel_handler.go

@@ -80,6 +80,9 @@ type BazelContext interface {
 	// Returns the results of GetOutputFiles and GetCcObjectFiles in a single query (in that order).
 	GetCcInfo(label string, archType ArchType) (cquery.CcInfo, bool, error)
 
+	// Returns the executable binary resultant from building together the python sources
+	GetPythonBinary(label string, archType ArchType) (string, bool)
+
 	// ** End cquery methods
 
 	// Issues commands to Bazel to receive results for all cquery requests
@@ -134,8 +137,9 @@ var _ BazelContext = noopBazelContext{}
 type MockBazelContext struct {
 	OutputBaseDir string
 
-	LabelToOutputFiles map[string][]string
-	LabelToCcInfo      map[string]cquery.CcInfo
+	LabelToOutputFiles  map[string][]string
+	LabelToCcInfo       map[string]cquery.CcInfo
+	LabelToPythonBinary map[string]string
 }
 
 func (m MockBazelContext) GetOutputFiles(label string, archType ArchType) ([]string, bool) {
@@ -148,6 +152,11 @@ func (m MockBazelContext) GetCcInfo(label string, archType ArchType) (cquery.CcI
 	return result, ok, nil
 }
 
+func (m MockBazelContext) GetPythonBinary(label string, archType ArchType) (string, bool) {
+	result, ok := m.LabelToPythonBinary[label]
+	return result, ok
+}
+
 func (m MockBazelContext) InvokeBazel() error {
 	panic("unimplemented")
 }
@@ -185,6 +194,16 @@ func (bazelCtx *bazelContext) GetCcInfo(label string, archType ArchType) (cquery
 	return ret, ok, err
 }
 
+func (bazelCtx *bazelContext) GetPythonBinary(label string, archType ArchType) (string, bool) {
+	rawString, ok := bazelCtx.cquery(label, cquery.GetPythonBinary, archType)
+	var ret string
+	if ok {
+		bazelOutput := strings.TrimSpace(rawString)
+		ret = cquery.GetPythonBinary.ParseResult(bazelOutput)
+	}
+	return ret, ok
+}
+
 func (n noopBazelContext) GetOutputFiles(label string, archType ArchType) ([]string, bool) {
 	panic("unimplemented")
 }
@@ -193,6 +212,10 @@ func (n noopBazelContext) GetCcInfo(label string, archType ArchType) (cquery.CcI
 	panic("unimplemented")
 }
 
+func (n noopBazelContext) GetPythonBinary(label string, archType ArchType) (string, bool) {
+	panic("unimplemented")
+}
+
 func (n noopBazelContext) GetPrebuiltCcStaticLibraryFiles(label string, archType ArchType) ([]string, bool) {
 	panic("unimplemented")
 }

bazel/cquery/request_type.go

@@ -6,8 +6,9 @@ import (
 )
 
 var (
-	GetOutputFiles = &getOutputFilesRequestType{}
-	GetCcInfo      = &getCcInfoType{}
+	GetOutputFiles  = &getOutputFilesRequestType{}
+	GetPythonBinary = &getPythonBinaryRequestType{}
+	GetCcInfo       = &getCcInfoType{}
 )
 
 type CcInfo struct {
@@ -28,6 +29,8 @@ type CcInfo struct {
 
 type getOutputFilesRequestType struct{}
 
+type getPythonBinaryRequestType struct{}
+
 // Name returns a string name for this request type. Such request type names must be unique,
 // and must only consist of alphanumeric characters.
 func (g getOutputFilesRequestType) Name() string {
@@ -53,6 +56,31 @@ func (g getOutputFilesRequestType) ParseResult(rawString string) []string {
 	return splitOrEmpty(rawString, ", ")
 }
 
+// Name returns a string name for this request type. Such request type names must be unique,
+// and must only consist of alphanumeric characters.
+func (g getPythonBinaryRequestType) Name() string {
+	return "getPythonBinary"
+}
+
+// StarlarkFunctionBody returns a starlark function body to process this request type.
+// The returned string is the body of a Starlark function which obtains
+// all request-relevant information about a target and returns a string containing
+// this information.
+// The function should have the following properties:
+//   - `target` is the only parameter to this function (a configured target).
+//   - The return value must be a string.
+//   - The function body should not be indented outside of its own scope.
+func (g getPythonBinaryRequestType) StarlarkFunctionBody() string {
+	return "return providers(target)['FilesToRunProvider'].executable.path"
+}
+
+// ParseResult returns a value obtained by parsing the result of the request's Starlark function.
+// The given rawString must correspond to the string output which was created by evaluating the
+// Starlark given in StarlarkFunctionBody.
+func (g getPythonBinaryRequestType) ParseResult(rawString string) string {
+	return rawString
+}
+
 type getCcInfoType struct{}
 
 // Name returns a string name for this request type. Such request type names must be unique,

bazel/cquery/request_type_test.go

@@ -37,6 +37,31 @@ func TestGetOutputFilesParseResults(t *testing.T) {
 	}
 }
 
+func TestGetPythonBinaryParseResults(t *testing.T) {
+	testCases := []struct {
+		description    string
+		input          string
+		expectedOutput string
+	}{
+		{
+			description:    "no result",
+			input:          "",
+			expectedOutput: "",
+		},
+		{
+			description:    "one result",
+			input:          "test",
+			expectedOutput: "test",
+		},
+	}
+	for _, tc := range testCases {
+		actualOutput := GetPythonBinary.ParseResult(tc.input)
+		if !reflect.DeepEqual(tc.expectedOutput, actualOutput) {
+			t.Errorf("%q: expected %#v != actual %#v", tc.description, tc.expectedOutput, actualOutput)
+		}
+	}
+}
+
 func TestGetCcInfoParseResults(t *testing.T) {
 	testCases := []struct {
 		description          string