Move compliance commands into subdirectories

Move each compliance command into its own directory to avoid Go tooling
considering all the files to be a single package and complaining about
conflicting global names.

Test: go test ./...
Change-Id: I3db6310e7368bcc7fe6a3704b40a84078ed44209

tools/compliance/cmd/listshare/listshare.go

@@ -0,0 +1,120 @@
+// Copyright 2021 Google LLC
+//
+// 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 (
+	"flag"
+	"fmt"
+	"io"
+	"os"
+	"path/filepath"
+	"sort"
+	"strings"
+
+	"android/soong/tools/compliance"
+)
+
+func init() {
+	flag.Usage = func() {
+		fmt.Fprintf(os.Stderr, `Usage: %s file.meta_lic {file.meta_lic...}
+
+Outputs a csv file with 1 project per line in the first field followed
+by target:condition pairs describing why the project must be shared.
+
+Each target is the path to a generated license metadata file for a
+Soong module or Make target, and the license condition is either
+restricted (e.g. GPL) or reciprocal (e.g. MPL).
+`, filepath.Base(os.Args[0]))
+	}
+}
+
+var (
+	failNoneRequested = fmt.Errorf("\nNo license metadata files requested")
+	failNoLicenses    = fmt.Errorf("No licenses found")
+)
+
+func main() {
+	flag.Parse()
+
+	// Must specify at least one root target.
+	if flag.NArg() == 0 {
+		flag.Usage()
+		os.Exit(2)
+	}
+
+	err := listShare(os.Stdout, os.Stderr, flag.Args()...)
+	if err != nil {
+		if err == failNoneRequested {
+			flag.Usage()
+		}
+		fmt.Fprintf(os.Stderr, "%s\n", err.Error())
+		os.Exit(1)
+	}
+	os.Exit(0)
+}
+
+// listShare implements the listshare utility.
+func listShare(stdout, stderr io.Writer, files ...string) error {
+	// Must be at least one root file.
+	if len(files) < 1 {
+		return failNoneRequested
+	}
+
+	// Read the license graph from the license metadata files (*.meta_lic).
+	licenseGraph, err := compliance.ReadLicenseGraph(os.DirFS("."), stderr, files)
+	if err != nil {
+		return fmt.Errorf("Unable to read license metadata file(s) %q: %v\n", files, err)
+	}
+	if licenseGraph == nil {
+		return failNoLicenses
+	}
+
+	// shareSource contains all source-sharing resolutions.
+	shareSource := compliance.ResolveSourceSharing(licenseGraph)
+
+	// Group the resolutions by project.
+	presolution := make(map[string]compliance.LicenseConditionSet)
+	for _, target := range shareSource.AttachesTo() {
+		rl := shareSource.Resolutions(target)
+		sort.Sort(rl)
+		for _, r := range rl {
+			for _, p := range r.ActsOn().Projects() {
+				if _, ok := presolution[p]; !ok {
+					presolution[p] = r.Resolves()
+					continue
+				}
+				presolution[p] = presolution[p].Union(r.Resolves())
+			}
+		}
+	}
+
+	// Sort the projects for repeatability/stability.
+	projects := make([]string, 0, len(presolution))
+	for p := range presolution {
+		projects = append(projects, p)
+	}
+	sort.Strings(projects)
+
+	// Output the sorted projects and the source-sharing license conditions that each project resolves.
+	for _, p := range projects {
+		if presolution[p].IsEmpty() {
+			fmt.Fprintf(stdout, "%s\n", p)
+		} else {
+			fmt.Fprintf(stdout, "%s,%s\n", p, strings.Join(presolution[p].Names(), ","))
+		}
+	}
+
+	return nil
+}