1 files changed, 126 insertions, 0 deletions
diff --git a/go/tools/gopackagesdriver/main.go b/go/tools/gopackagesdriver/main.go
new file mode 100644
index 00000000..fea2d2c1
--- /dev/null
+++ b/go/tools/gopackagesdriver/main.go
@@ -0,0 +1,126 @@
+// Copyright 2021 The Bazel Authors. 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 main
+
+import (
+	"context"
+	"encoding/json"
+	"fmt"
+	"go/types"
+	"os"
+	"strings"
+)
+
+type driverResponse struct {
+	// NotHandled is returned if the request can't be handled by the current
+	// driver. If an external driver returns a response with NotHandled, the
+	// rest of the driverResponse is ignored, and go/packages will fallback
+	// to the next driver. If go/packages is extended in the future to support
+	// lists of multiple drivers, go/packages will fall back to the next driver.
+	NotHandled bool
+
+	// Sizes, if not nil, is the types.Sizes to use when type checking.
+	Sizes *types.StdSizes
+
+	// Roots is the set of package IDs that make up the root packages.
+	// We have to encode this separately because when we encode a single package
+	// we cannot know if it is one of the roots as that requires knowledge of the
+	// graph it is part of.
+	Roots []string `json:",omitempty"`
+
+	// Packages is the full set of packages in the graph.
+	// The packages are not connected into a graph.
+	// The Imports if populated will be stubs that only have their ID set.
+	// Imports will be connected and then type and syntax information added in a
+	// later pass (see refine).
+	Packages []*FlatPackage
+}
+
+var (
+	// Injected via x_defs.
+
+	rulesGoRepositoryName string
+	goDefaultAspect       = rulesGoRepositoryName + "//go/tools/gopackagesdriver:aspect.bzl%go_pkg_info_aspect"
+	bazelBin              = getenvDefault("GOPACKAGESDRIVER_BAZEL", "bazel")
+	bazelStartupFlags     = strings.Fields(os.Getenv("GOPACKAGESDRIVER_BAZEL_FLAGS"))
+	bazelQueryFlags       = strings.Fields(os.Getenv("GOPACKAGESDRIVER_BAZEL_QUERY_FLAGS"))
+	bazelQueryScope       = getenvDefault("GOPACKAGESDRIVER_BAZEL_QUERY_SCOPE", "")
+	bazelBuildFlags       = strings.Fields(os.Getenv("GOPACKAGESDRIVER_BAZEL_BUILD_FLAGS"))
+	workspaceRoot         = os.Getenv("BUILD_WORKSPACE_DIRECTORY")
+	additionalAspects     = strings.Fields(os.Getenv("GOPACKAGESDRIVER_BAZEL_ADDTL_ASPECTS"))
+	additionalKinds       = strings.Fields(os.Getenv("GOPACKAGESDRIVER_BAZEL_KINDS"))
+	emptyResponse         = &driverResponse{
+		NotHandled: true,
+		Sizes:      types.SizesFor("gc", "amd64").(*types.StdSizes),
+		Roots:      []string{},
+		Packages:   []*FlatPackage{},
+	}
+)
+
+func run() (*driverResponse, error) {
+	ctx, cancel := signalContext(context.Background(), os.Interrupt)
+	defer cancel()
+
+	queries := os.Args[1:]
+
+	request, err := ReadDriverRequest(os.Stdin)
+	if err != nil {
+		return emptyResponse, fmt.Errorf("unable to read request: %w", err)
+	}
+
+	bazel, err := NewBazel(ctx, bazelBin, workspaceRoot, bazelStartupFlags)
+	if err != nil {
+		return emptyResponse, fmt.Errorf("unable to create bazel instance: %w", err)
+	}
+
+	bazelJsonBuilder, err := NewBazelJSONBuilder(bazel, request.Tests)
+	if err != nil {
+		return emptyResponse, fmt.Errorf("unable to build JSON files: %w", err)
+	}
+
+	labels, err := bazelJsonBuilder.Labels(ctx, queries)
+	if err != nil {
+		return emptyResponse, fmt.Errorf("unable to lookup package: %w", err)
+	}
+
+	jsonFiles, err := bazelJsonBuilder.Build(ctx, labels, request.Mode)
+	if err != nil {
+		return emptyResponse, fmt.Errorf("unable to build JSON files: %w", err)
+	}
+
+	driver, err := NewJSONPackagesDriver(jsonFiles, bazelJsonBuilder.PathResolver())
+	if err != nil {
+		return emptyResponse, fmt.Errorf("unable to load JSON files: %w", err)
+	}
+
+	// Note: we are returning all files required to build a specific package.
+	// For file queries (`file=`), this means that the CompiledGoFiles will
+	// include more than the only file being specified.
+	return driver.GetResponse(labels), nil
+}
+
+func main() {
+	response, err := run()
+	if err := json.NewEncoder(os.Stdout).Encode(response); err != nil {
+		fmt.Fprintf(os.Stderr, "unable to encode response: %v", err)
+	}
+	if err != nil {
+		fmt.Fprintf(os.Stderr, "error: %v", err)
+		// gopls will check the packages driver exit code, and if there is an
+		// error, it will fall back to go list. Obviously we don't want that,
+		// so force a 0 exit code.
+		os.Exit(0)
+	}
+}