Set system property from list of backported fixes

Because the caluculation of a BitSet is
to compicated for make a genrule and java are
used to ro.build.backported_fixes.alias_bitset.long_list to the end of
the system property file.

This part of the API for backported fixes.  See go/android-backported-fixes-spec

Bug: 377727445
Test: atest applied_backported_fixes_test backported_fixes_common_test
Change-Id: I2621e2fb52401495f796a5a4db330c5dfafbda40

3 files changed, 217 insertions, 0 deletions

diff --git a/backported_fixes/src/java/com/android/build/backportedfixes/Main.java b/backported_fixes/src/java/com/android/build/backportedfixes/Main.java
new file mode 100644
index 0000000000..79148cc838
--- /dev/null
+++ b/backported_fixes/src/java/com/android/build/backportedfixes/Main.java
@@ -0,0 +1,79 @@
+
+/*
+ * Copyright (C) 2024 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 com.android.build.backportedfixes;
+
+import static java.nio.charset.StandardCharsets.UTF_8;
+
+import com.android.build.backportedfixes.common.ClosableCollection;
+import com.android.build.backportedfixes.common.Parser;
+
+import com.beust.jcommander.JCommander;
+import com.beust.jcommander.Parameter;
+import com.beust.jcommander.converters.FileConverter;
+import com.google.common.io.Files;
+
+import java.io.File;
+import java.io.PrintWriter;
+import java.io.Writer;
+import java.util.Arrays;
+import java.util.List;
+import java.util.stream.Collectors;
+
+public final class Main {
+    @Parameter(description = "BackportedFix proto binary files", converter = FileConverter.class,
+            required = true)
+    List<File> fixFiles;
+    @Parameter(description = "The file to write the property value to.",
+            names = {"--property_file", "-p"}, converter = FileConverter.class, required = true)
+    File propertyFile;
+
+    public static void main(String... argv) throws Exception {
+        Main main = new Main();
+        JCommander.newBuilder().addObject(main).build().parse(argv);
+        main.run();
+    }
+
+    Main() {
+    }
+
+    private void run() throws Exception {
+        try (var fixStreams = ClosableCollection.wrap(Parser.getFileInputStreams(fixFiles));
+             var out = Files.newWriter(propertyFile, UTF_8)) {
+            var fixes = Parser.parseBackportedFixes(fixStreams.getCollection());
+            writeFixesAsAliasBitSet(fixes, out);
+        }
+    }
+
+    static void writeFixesAsAliasBitSet(BackportedFixes fixes, Writer out) {
+        PrintWriter printWriter = new PrintWriter(out);
+        printWriter.println("# The following backported fixes have been applied");
+        for (var f : fixes.getFixesList()) {
+            printWriter.printf("# https://issuetracker.google.com/issues/%d with alias %d",
+                    f.getKnownIssue(), f.getAlias());
+            printWriter.println();
+        }
+        var bsArray = Parser.getBitSetArray(
+                fixes.getFixesList().stream().mapToInt(BackportedFix::getAlias).toArray());
+        String bsString = Arrays.stream(bsArray).mapToObj(Long::toString).collect(
+                Collectors.joining(","));
+        printWriter.printf("ro.build.backported_fixes.alias_bitset.long_list=%s", bsString);
+        printWriter.println();
+        if (printWriter.checkError()) {
+            throw new RuntimeException("There was an error writing to " + out.toString());
+        }
+    }
+}
diff --git a/backported_fixes/src/java/com/android/build/backportedfixes/common/ClosableCollection.java b/backported_fixes/src/java/com/android/build/backportedfixes/common/ClosableCollection.java
new file mode 100644
index 0000000000..75b6730c88
--- /dev/null
+++ b/backported_fixes/src/java/com/android/build/backportedfixes/common/ClosableCollection.java
@@ -0,0 +1,67 @@
+/*
+ * Copyright (C) 2024 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 com.android.build.backportedfixes.common;
+
+import com.google.common.collect.ImmutableList;
+
+import java.util.ArrayList;
+import java.util.Collection;
+
+/** An AutoCloseable holder for a collection of AutoCloseables. */
+public final class ClosableCollection<T extends AutoCloseable, C extends Collection<T>> implements
+        AutoCloseable {
+    C source;
+
+    /** Makes the collection AutoCloseable. */
+    public static <T extends AutoCloseable, C extends Collection<T>> ClosableCollection<T, C> wrap(
+            C source) {
+        return new ClosableCollection<>(source);
+    }
+
+    private ClosableCollection(C source) {
+        this.source = source;
+    }
+
+    /** Get the source collection. */
+    public C getCollection() {
+        return source;
+    }
+
+    /**
+     * Closes each item in the collection.
+     *
+     * @throws Exception if any close throws an an exception, a new exception is thrown with
+     *                   all the exceptions thrown closing the streams added as a suppressed
+     *                   exceptions.
+     */
+    @Override
+    public void close() throws Exception {
+        var failures = new ArrayList<Exception>();
+        for (T t : source) {
+            try {
+                t.close();
+            } catch (Exception e) {
+                failures.add(e);
+            }
+        }
+        if (!failures.isEmpty()) {
+            Exception e = new Exception(
+                    "%d of %d failed while closing".formatted(failures.size(), source.size()));
+            failures.forEach(e::addSuppressed);
+            throw e;
+        }
+    }
+}
diff --git a/backported_fixes/src/java/com/android/build/backportedfixes/common/Parser.java b/backported_fixes/src/java/com/android/build/backportedfixes/common/Parser.java
new file mode 100644
index 0000000000..6b08b8f3b3
--- /dev/null
+++ b/backported_fixes/src/java/com/android/build/backportedfixes/common/Parser.java
@@ -0,0 +1,71 @@
+/*
+ * Copyright (C) 2024 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 com.android.build.backportedfixes.common;
+
+import com.android.build.backportedfixes.BackportedFix;
+import com.android.build.backportedfixes.BackportedFixes;
+
+import com.google.common.collect.ImmutableList;
+
+import java.io.File;
+import java.io.FileInputStream;
+import java.io.FileNotFoundException;
+import java.io.IOException;
+import java.io.InputStream;
+import java.util.BitSet;
+import java.util.List;
+
+
+/** Static utilities for working with {@link BackportedFixes}. */
+public final class Parser {
+
+    /** Creates list of FileInputStreams for a list of files. */
+    public static ImmutableList<FileInputStream> getFileInputStreams(List<File> fixFiles) throws
+            FileNotFoundException {
+        var streams = ImmutableList.<FileInputStream>builder();
+        for (var f : fixFiles) {
+            streams.add(new FileInputStream(f));
+        }
+        return streams.build();
+    }
+
+    /** Converts a list of backported fix aliases into a long array representing a {@link BitSet} */
+    public static long[] getBitSetArray(int[] aliases) {
+        BitSet bs = new BitSet();
+        for (int a : aliases) {
+            bs.set(a);
+        }
+        return bs.toLongArray();
+    }
+
+    /**
+     * Creates a {@link BackportedFixes} from a list of {@link BackportedFix} binary proto streams.
+     */
+    public static BackportedFixes parseBackportedFixes(List<? extends InputStream> fixStreams)
+            throws
+            IOException {
+        var fixes = BackportedFixes.newBuilder();
+        for (var s : fixStreams) {
+            BackportedFix fix = BackportedFix.parseFrom(s);
+            fixes.addFixes(fix);
+            s.close();
+        }
+        return fixes.build();
+    }
+
+    private Parser() {
+    }
+}