1 files changed, 250 insertions, 0 deletions
diff --git a/go/tools/gopackagesdriver/bazel_json_builder.go b/go/tools/gopackagesdriver/bazel_json_builder.go
new file mode 100644
index 00000000..163be082
--- /dev/null
+++ b/go/tools/gopackagesdriver/bazel_json_builder.go
@@ -0,0 +1,250 @@
+// 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 (
+	"bufio"
+	"context"
+	"errors"
+	"fmt"
+	"io/ioutil"
+	"os"
+	"path"
+	"path/filepath"
+	"regexp"
+	"strings"
+)
+
+type BazelJSONBuilder struct {
+	bazel        *Bazel
+	includeTests bool
+}
+
+var RulesGoStdlibLabel = rulesGoRepositoryName + "//:stdlib"
+
+var _defaultKinds = []string{"go_library", "go_test", "go_binary"}
+
+var externalRe = regexp.MustCompile(".*\\/external\\/([^\\/]+)(\\/(.*))?\\/([^\\/]+.go)")
+
+func (b *BazelJSONBuilder) fileQuery(filename string) string {
+	label := filename
+
+	if filepath.IsAbs(filename) {
+		label, _ = filepath.Rel(b.bazel.WorkspaceRoot(), filename)
+	} else if strings.HasPrefix(filename, "./") {
+		label = strings.TrimPrefix(filename, "./")
+	}
+
+	if matches := externalRe.FindStringSubmatch(filename); len(matches) == 5 {
+		// if filepath is for a third party lib, we need to know, what external
+		// library this file is part of.
+		matches = append(matches[:2], matches[3:]...)
+		label = fmt.Sprintf("@%s//%s", matches[1], strings.Join(matches[2:], ":"))
+	}
+
+	relToBin, err := filepath.Rel(b.bazel.info["output_path"], filename)
+	if err == nil && !strings.HasPrefix(relToBin, "../") {
+		parts := strings.SplitN(relToBin, string(filepath.Separator), 3)
+		relToBin = parts[2]
+		// We've effectively converted filename from bazel-bin/some/path.go to some/path.go;
+		// Check if a BUILD.bazel files exists under this dir, if not walk up and repeat.
+		relToBin = filepath.Dir(relToBin)
+		_, err = os.Stat(filepath.Join(b.bazel.WorkspaceRoot(), relToBin, "BUILD.bazel"))
+		for errors.Is(err, os.ErrNotExist) && relToBin != "." {
+			relToBin = filepath.Dir(relToBin)
+			_, err = os.Stat(filepath.Join(b.bazel.WorkspaceRoot(), relToBin, "BUILD.bazel"))
+		}
+
+		if err == nil {
+			// return package path found and build all targets (codegen doesn't fall under go_library)
+			// Otherwise fallback to default
+			if relToBin == "." {
+				relToBin = ""
+			}
+			label = fmt.Sprintf("//%s:all", relToBin)
+			additionalKinds = append(additionalKinds, "go_.*")
+		}
+	}
+
+	kinds := append(_defaultKinds, additionalKinds...)
+	return fmt.Sprintf(`kind("%s", same_pkg_direct_rdeps("%s"))`, strings.Join(kinds, "|"), label)
+}
+
+func (b *BazelJSONBuilder) getKind() string {
+	kinds := []string{"go_library"}
+	if b.includeTests {
+		kinds = append(kinds, "go_test")
+	}
+
+	return strings.Join(kinds, "|")
+}
+
+func (b *BazelJSONBuilder) localQuery(request string) string {
+	request = path.Clean(request)
+	if filepath.IsAbs(request) {
+		if relPath, err := filepath.Rel(workspaceRoot, request); err == nil {
+			request = relPath
+		}
+	}
+
+	if !strings.HasSuffix(request, "...") {
+		request = fmt.Sprintf("%s:*", request)
+	}
+
+	return fmt.Sprintf(`kind("%s", %s)`, b.getKind(), request)
+}
+
+func (b *BazelJSONBuilder) packageQuery(importPath string) string {
+	if strings.HasSuffix(importPath, "/...") {
+		importPath = fmt.Sprintf(`^%s(/.+)?$`, strings.TrimSuffix(importPath, "/..."))
+	}
+
+	return fmt.Sprintf(
+		`kind("%s", attr(importpath, "%s", deps(%s)))`,
+		b.getKind(),
+		importPath,
+		bazelQueryScope)
+}
+
+func (b *BazelJSONBuilder) queryFromRequests(requests ...string) string {
+	ret := make([]string, 0, len(requests))
+	for _, request := range requests {
+		result := ""
+		if strings.HasSuffix(request, ".go") {
+			f := strings.TrimPrefix(request, "file=")
+			result = b.fileQuery(f)
+		} else if isLocalPattern(request) {
+			result = b.localQuery(request)
+		} else if request == "builtin" || request == "std" {
+			result = fmt.Sprintf(RulesGoStdlibLabel)
+		} else if bazelQueryScope != "" {
+			result = b.packageQuery(request)
+		}
+
+		if result != "" {
+			ret = append(ret, result)
+		}
+	}
+	if len(ret) == 0 {
+		return RulesGoStdlibLabel
+	}
+	return strings.Join(ret, " union ")
+}
+
+func NewBazelJSONBuilder(bazel *Bazel, includeTests bool) (*BazelJSONBuilder, error) {
+	return &BazelJSONBuilder{
+		bazel:        bazel,
+		includeTests: includeTests,
+	}, nil
+}
+
+func (b *BazelJSONBuilder) outputGroupsForMode(mode LoadMode) string {
+	og := "go_pkg_driver_json_file,go_pkg_driver_stdlib_json_file,go_pkg_driver_srcs"
+	if mode&NeedExportsFile != 0 {
+		og += ",go_pkg_driver_export_file"
+	}
+	return og
+}
+
+func (b *BazelJSONBuilder) query(ctx context.Context, query string) ([]string, error) {
+	queryArgs := concatStringsArrays(bazelQueryFlags, []string{
+		"--ui_event_filters=-info,-stderr",
+		"--noshow_progress",
+		"--order_output=no",
+		"--output=label",
+		"--nodep_deps",
+		"--noimplicit_deps",
+		"--notool_deps",
+		query,
+	})
+	labels, err := b.bazel.Query(ctx, queryArgs...)
+	if err != nil {
+		return nil, fmt.Errorf("unable to query: %w", err)
+	}
+
+	return labels, nil
+}
+
+func (b *BazelJSONBuilder) Labels(ctx context.Context, requests []string) ([]string, error) {
+	labels, err := b.query(ctx, b.queryFromRequests(requests...))
+	if err != nil {
+		return nil, fmt.Errorf("query failed: %w", err)
+	}
+
+	if len(labels) == 0 {
+		return nil, fmt.Errorf("found no labels matching the requests")
+	}
+
+	return labels, nil
+}
+
+func (b *BazelJSONBuilder) Build(ctx context.Context, labels []string, mode LoadMode) ([]string, error) {
+	aspects := append(additionalAspects, goDefaultAspect)
+
+	buildArgs := concatStringsArrays([]string{
+		"--experimental_convenience_symlinks=ignore",
+		"--ui_event_filters=-info,-stderr",
+		"--noshow_progress",
+		"--aspects=" + strings.Join(aspects, ","),
+		"--output_groups=" + b.outputGroupsForMode(mode),
+		"--keep_going", // Build all possible packages
+	}, bazelBuildFlags)
+
+	if len(labels) < 100 {
+		buildArgs = append(buildArgs, labels...)
+	} else {
+		// To avoid hitting MAX_ARGS length, write labels to a file and use `--target_pattern_file`
+		targetsFile, err := ioutil.TempFile("", "gopackagesdriver_targets_")
+		if err != nil {
+			return nil, fmt.Errorf("unable to create target pattern file: %w", err)
+		}
+		writer := bufio.NewWriter(targetsFile)
+		defer writer.Flush()
+		for _, l := range labels {
+			writer.WriteString(l + "\n")
+		}
+		if err := writer.Flush(); err != nil {
+			return nil, fmt.Errorf("unable to flush data to target pattern file: %w", err)
+		}
+		defer func() {
+			targetsFile.Close()
+			os.Remove(targetsFile.Name())
+		}()
+
+		buildArgs = append(buildArgs, "--target_pattern_file="+targetsFile.Name())
+	}
+	files, err := b.bazel.Build(ctx, buildArgs...)
+	if err != nil {
+		return nil, fmt.Errorf("unable to bazel build %v: %w", buildArgs, err)
+	}
+
+	ret := []string{}
+	for _, f := range files {
+		if strings.HasSuffix(f, ".pkg.json") {
+			ret = append(ret, f)
+		}
+	}
+
+	return ret, nil
+}
+
+func (b *BazelJSONBuilder) PathResolver() PathResolverFunc {
+	return func(p string) string {
+		p = strings.Replace(p, "__BAZEL_EXECROOT__", b.bazel.ExecutionRoot(), 1)
+		p = strings.Replace(p, "__BAZEL_WORKSPACE__", b.bazel.WorkspaceRoot(), 1)
+		p = strings.Replace(p, "__BAZEL_OUTPUT_BASE__", b.bazel.OutputBase(), 1)
+		return p
+	}
+}