Implement license notice generator for Bazel.

Bug: 190817312
Test: treehugger
Change-Id: I36521c0a91e5c7e09745407b7ab50f8e91c7296d

5 files changed, 333 insertions, 0 deletions

diff --git a/compliance/Android.bp b/compliance/Android.bp
new file mode 100644
index 00000000..0e709429
--- /dev/null
+++ b/compliance/Android.bp
@@ -0,0 +1,24 @@
+//
+// Copyright (C) 2022 The Android Open Source Project
+//
+// 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 {
+    default_applicable_licenses: ["Android-Apache-2.0"],
+}
+
+blueprint_go_binary {
+    name: "bazel_notice_gen",
+    srcs: ["cmd/bazel_notice_gen/bazel_notice_gen.go"],
+    testSrcs: ["cmd/bazel_notice_gen/bazel_notice_gen_test.go"],
+}
diff --git a/compliance/cmd/bazel_notice_gen/bazel_notice_gen.go b/compliance/cmd/bazel_notice_gen/bazel_notice_gen.go
new file mode 100644
index 00000000..75a206cc
--- /dev/null
+++ b/compliance/cmd/bazel_notice_gen/bazel_notice_gen.go
@@ -0,0 +1,174 @@
+// Copyright 2022 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 (
+	"compress/gzip"
+	"crypto/md5"
+	"encoding/json"
+	"flag"
+	"fmt"
+	"html/template"
+	"io"
+	"os"
+	"strings"
+)
+
+var (
+	inputFile   string
+	outputFile  = flag.String("o", "", "output file")
+	listTargets = flag.Bool("list_targets", false, "list targets using each license")
+)
+
+type LicenseKind struct {
+	Target     string   `json:"target"`
+	Name       string   `json:"name"`
+	Conditions []string `json:"conditions"`
+}
+
+type License struct {
+	Rule            string        `json:"rule"`
+	CopyrightNotice string        `json:"copyright_notice"`
+	PackageName     string        `json:"package_name"`
+	PackageUrl      string        `json:"package_url"`
+	PackageVersion  string        `json:"package_version"`
+	LicenseFile     string        `json:"license_text"`
+	LicenseKinds    []LicenseKind `json:"license_kinds"`
+	Licensees       []string      `json:"licensees"`
+}
+
+type LicenseTextHash string
+
+// generator generates the notices for the given set of licenses read from the JSON-encoded string.
+// As the contents of the license files is often the same, they are read into the map by their hash.
+type generator struct {
+	Licenses         []License
+	LicenseTextHash  map[string]LicenseTextHash // License.rule->hash of license text contents
+	LicenseTextIndex map[LicenseTextHash]string
+}
+
+func newGenerator(in string) *generator {
+	g := generator{}
+	decoder := json.NewDecoder(strings.NewReader(in))
+	decoder.DisallowUnknownFields() //useful to detect typos, e.g. in unit tests
+	err := decoder.Decode(&g.Licenses)
+	maybeQuit(err)
+	return &g
+}
+
+func (g *generator) buildLicenseTextIndex() {
+	g.LicenseTextHash = make(map[string]LicenseTextHash, len(g.Licenses))
+	g.LicenseTextIndex = make(map[LicenseTextHash]string)
+	for _, l := range g.Licenses {
+		if l.LicenseFile == "" {
+			continue
+		}
+		data, err := os.ReadFile(l.LicenseFile)
+		if err != nil {
+			fmt.Fprintf(os.Stderr, "%s: bad license file %s: %s\n", l.Rule, l.LicenseFile, err)
+			os.Exit(1)
+		}
+		h := LicenseTextHash(fmt.Sprintf("%x", md5.Sum(data)))
+		g.LicenseTextHash[l.Rule] = h
+		if _, found := g.LicenseTextIndex[h]; !found {
+			g.LicenseTextIndex[h] = string(data)
+		}
+	}
+}
+
+func (g *generator) generate(sink io.Writer, listTargets bool) {
+	const tpl = `<!DOCTYPE html>
+<html>
+  <head>
+    <style type="text/css">
+      body { padding: 2px; margin: 0; }
+      .license { background-color: seashell; margin: 1em;}
+      pre { padding: 1em; }</style></head>
+  <body>
+    The following software has been included in this product and contains the license and notice as shown below.<p>
+    {{- $x := . }}
+	{{- range .Licenses }}
+    {{ if .PackageName  }}<strong>{{.PackageName}}</strong>{{- else }}Rule: {{.Rule}}{{ end }}
+    {{- if .CopyrightNotice }}<br>Copyright Notice: {{.CopyrightNotice}}{{ end }}
+    {{- $v := index $x.LicenseTextHash .Rule }}{{- if $v }}<br><a href=#{{$v}}>License</a>{{- end }}<br>
+    {{- if list_targets }}
+    Used by: {{- range .Licensees }} {{.}} {{- end }}<hr>
+    {{- end }}
+    {{- end }}
+    {{ range $k, $v := .LicenseTextIndex }}<div id="{{$k}}" class="license"><pre>{{$v}}
+    </pre></div> {{- end }}
+  </body>
+</html>
+`
+	funcMap := template.FuncMap{
+		"list_targets": func() bool { return listTargets },
+	}
+	t, err := template.New("NoticesPage").Funcs(funcMap).Parse(tpl)
+	maybeQuit(err)
+	if g.LicenseTextHash == nil {
+		g.buildLicenseTextIndex()
+	}
+	maybeQuit(t.Execute(sink, g))
+}
+
+func maybeQuit(err error) {
+	if err == nil {
+		return
+	}
+
+	fmt.Fprintln(os.Stderr, err)
+	os.Exit(1)
+}
+
+func processArgs() {
+	flag.Usage = func() {
+		fmt.Fprintln(os.Stderr, `usage: bazelhtmlnotice -o <output> <input>`)
+		flag.PrintDefaults()
+		os.Exit(2)
+	}
+	flag.Parse()
+	if len(flag.Args()) != 1 {
+		flag.Usage()
+	}
+	inputFile = flag.Arg(0)
+}
+
+func setupWriting() (io.Writer, io.Closer, *os.File) {
+	if *outputFile == "" {
+		return os.Stdout, nil, nil
+	}
+	ofile, err := os.Create(*outputFile)
+	maybeQuit(err)
+	if !strings.HasSuffix(*outputFile, ".gz") {
+		return ofile, nil, ofile
+	}
+	gz, err := gzip.NewWriterLevel(ofile, gzip.BestCompression)
+	maybeQuit(err)
+	return gz, gz, ofile
+}
+
+func main() {
+	processArgs()
+	data, err := os.ReadFile(inputFile)
+	maybeQuit(err)
+	sink, closer, ofile := setupWriting()
+	newGenerator(string(data)).generate(sink, *listTargets)
+	if closer != nil {
+		maybeQuit(closer.Close())
+	}
+	if ofile != nil {
+		maybeQuit(ofile.Close())
+	}
+}
diff --git a/compliance/cmd/bazel_notice_gen/bazel_notice_gen_test.go b/compliance/cmd/bazel_notice_gen/bazel_notice_gen_test.go
new file mode 100644
index 00000000..31953871
--- /dev/null
+++ b/compliance/cmd/bazel_notice_gen/bazel_notice_gen_test.go
@@ -0,0 +1,128 @@
+// Copyright 2022 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 (
+	"bytes"
+	"testing"
+)
+
+func Test_doit(t *testing.T) {
+	input := `
+[
+  {
+    "rule": "@//build/soong/licenses:Android-Apache-2.0",
+    "license_kinds": [
+      {
+        "target": "@//build/soong/licenses:SPDX-license-identifier-Apache-2.0",
+        "name": "SPDX-license-identifier-Apache-2.0",
+        "conditions": ["notice"]
+      }
+    ],
+    "copyright_notice": "Copyright (C) The Android Open Source Project",
+    "package_name": "Discombobulator",
+    "package_url": null,
+    "package_version": null,
+    "license_text": "../../testdata/NOTICE_LICENSE",
+	"licensees": [
+        "@//bionic/libc:libc_bionic_ndk",
+		"@//system/logging/liblog:liblog"
+    ]
+ },
+ {
+    "rule": "@//external/scudo:external_scudo_license",
+    "license_kinds": [
+      {
+        "target": "@//build/soong/licenses:SPDX-license-identifier-Apache-2.0",
+        "name": "SPDX-license-identifier-Apache-2.0",
+        "conditions": ["notice"]
+      }
+    ],
+    "copyright_notice": "",
+    "package_name": "Scudo Standalone",
+    "package_url": null,
+    "package_version": null,
+	"licensees": [
+        "@//external/scudo:foo"
+    ]
+  }
+]
+`
+	tests := []struct {
+		name        string
+		in          string
+		listTargets bool
+		want        string
+	}{
+		{
+			name:        "ListTargets",
+			in:          input,
+			listTargets: true,
+			want: `<!DOCTYPE html>
+<html>
+  <head>
+    <style type="text/css">
+      body { padding: 2px; margin: 0; }
+      .license { background-color: seashell; margin: 1em;}
+      pre { padding: 1em; }</style></head>
+  <body>
+    The following software has been included in this product and contains the license and notice as shown below.<p>
+    <strong>Discombobulator</strong><br>Copyright Notice: Copyright (C) The Android Open Source Project<br><a href=#b9835e4a000fb18a4c8970690daa3b95>License</a><br>
+    Used by: @//bionic/libc:libc_bionic_ndk @//system/logging/liblog:liblog<hr>
+    <strong>Scudo Standalone</strong><br>
+    Used by: @//external/scudo:foo<hr>
+    <div id="b9835e4a000fb18a4c8970690daa3b95" class="license"><pre>neque porro quisquam est qui do-
+lorem ipsum
+
+    </pre></div>
+  </body>
+</html>
+`,
+		},
+		{
+			name:        "NoTargets",
+			in:          input,
+			listTargets: false,
+			want: `<!DOCTYPE html>
+<html>
+  <head>
+    <style type="text/css">
+      body { padding: 2px; margin: 0; }
+      .license { background-color: seashell; margin: 1em;}
+      pre { padding: 1em; }</style></head>
+  <body>
+    The following software has been included in this product and contains the license and notice as shown below.<p>
+    <strong>Discombobulator</strong><br>Copyright Notice: Copyright (C) The Android Open Source Project<br><a href=#b9835e4a000fb18a4c8970690daa3b95>License</a><br>
+    <strong>Scudo Standalone</strong><br>
+    <div id="b9835e4a000fb18a4c8970690daa3b95" class="license"><pre>neque porro quisquam est qui do-
+lorem ipsum
+
+    </pre></div>
+  </body>
+</html>
+`,
+		},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			buf := bytes.Buffer{}
+			newGenerator(tt.in).generate(&buf, tt.listTargets)
+			got := buf.String()
+			if got != tt.want {
+				t.Errorf("doit() = %v, want %v", got, tt.want)
+			}
+		})
+	}
+}
diff --git a/compliance/go.mod b/compliance/go.mod
new file mode 100644
index 00000000..336254d2
--- /dev/null
+++ b/compliance/go.mod
@@ -0,0 +1,5 @@
+module android/bazel/compliance
+
+
+
+go 1.19
diff --git a/compliance/testdata/NOTICE_LICENSE b/compliance/testdata/NOTICE_LICENSE
new file mode 100644
index 00000000..da74c170
--- /dev/null
+++ b/compliance/testdata/NOTICE_LICENSE
@@ -0,0 +1,2 @@
+neque porro quisquam est qui do-
+lorem ipsum