Parse protos in library

Bug: 342636474
Test: m
Change-Id: I4934fa2332b00084f73453945d6b4743566f6e48

tools/aconfig/aconfig_device_paths/Android.bp

@@ -39,8 +39,8 @@ rust_library {
 
 genrule {
     name: "libaconfig_java_device_paths_src",
-    srcs: ["src/DevicePathsTemplate.java"],
-    out: ["DevicePaths.java"],
+    srcs: ["src/DeviceProtosTemplate.java"],
+    out: ["DeviceProtos.java"],
     tool_files: ["partition_aconfig_flags_paths.txt"],
     cmd: "sed -e '/TEMPLATE/{r$(location partition_aconfig_flags_paths.txt)' -e 'd}' $(in) > $(out)",
 }
@@ -48,5 +48,7 @@ genrule {
 java_library {
     name: "aconfig_device_paths_java",
     srcs: [":libaconfig_java_device_paths_src"],
-    sdk_version: "core_current",
+    static_libs: [
+        "libaconfig_java_proto_nano",
+    ],
 }

tools/aconfig/aconfig_device_paths/src/DeviceProtosTemplate.java

@@ -15,7 +15,12 @@
  */
 package android.aconfig;
 
+import android.aconfig.nano.Aconfig.parsed_flag;
+import android.aconfig.nano.Aconfig.parsed_flags;
+
 import java.io.File;
+import java.io.FileInputStream;
+import java.io.IOException;
 import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.List;
@@ -23,7 +28,7 @@ import java.util.List;
 /**
  * @hide
  */
-public class DevicePaths {
+public class DeviceProtos {
     static final String[] PATHS = {
         TEMPLATE
     };
@@ -31,12 +36,35 @@ public class DevicePaths {
     private static final String APEX_DIR = "/apex";
     private static final String APEX_ACONFIG_PATH_SUFFIX = "/etc/aconfig_flags.pb";
 
+    /**
+     * Returns a list of all on-device aconfig protos.
+     *
+     * May throw an exception if the protos can't be read at the call site. For
+     * example, some of the protos are in the apex/ partition, which is mounted
+     * somewhat late in the boot process.
+     *
+     * @throws IOException if we can't read one of the protos yet
+     * @return a list of all on-device aconfig protos
+     */
+    public static List<parsed_flag> loadAndParseFlagProtos() throws IOException {
+        ArrayList<parsed_flag> result = new ArrayList();
+
+        for (String path : parsedFlagsProtoPaths()) {
+            FileInputStream inputStream = new FileInputStream(path);
+            parsed_flags parsedFlags = parsed_flags.parseFrom(inputStream.readAllBytes());
+            for (parsed_flag flag : parsedFlags.parsedFlag) {
+                result.add(flag);
+            }
+        }
+
+        return result;
+    }
 
     /**
      * Returns the list of all on-device aconfig protos paths.
      * @hide
      */
-    public static List<String> parsedFlagsProtoPaths() {
+    private static List<String> parsedFlagsProtoPaths() {
         ArrayList<String> paths = new ArrayList(Arrays.asList(PATHS));
 
         File apexDirectory = new File(APEX_DIR);