feat: add shorebird_current_boot_patch_number function (#36)

* feat: add shorebird_current_boot_patch_number function

* Continue support for next_patch_version

* rename, return null in case of 0

shorebird_code_push/lib/src/generated/updater_bindings.g.dart

@@ -2084,6 +2084,18 @@ class UpdaterBindings {
   late final _shorebird_init = _shorebird_initPtr.asFunction<
       bool Function(ffi.Pointer<AppParameters>, ffi.Pointer<ffi.Char>)>();
 
+  /// The currently running patch number, or 0 if the release has not been
+  /// patched.
+  int shorebird_current_boot_patch_number() {
+    return _shorebird_current_boot_patch_number();
+  }
+
+  late final _shorebird_current_boot_patch_numberPtr =
+      _lookup<ffi.NativeFunction<ffi.UintPtr Function()>>(
+          'shorebird_current_boot_patch_number');
+  late final _shorebird_current_boot_patch_number =
+      _shorebird_current_boot_patch_numberPtr.asFunction<int Function()>();
+
   /// The patch number that will boot on the next run of the app, or 0 if there is
   /// no next patch.
   int shorebird_next_boot_patch_number() {
@@ -2157,8 +2169,9 @@ class UpdaterBindings {
       _shorebird_start_update_threadPtr.asFunction<void Function()>();
 
   /// Tell the updater that we're launching from what it told us was the
-  /// next patch to boot from.  This will copy the next_boot patch to be
-  /// the current_boot patch.
+  /// next patch to boot from. This will copy the next_boot patch to be the
+  /// current_boot patch.
+  ///
   /// It is required to call this function before calling
   /// shorebird_report_launch_success or shorebird_report_launch_failure.
   void shorebird_report_launch_start() {
@@ -2188,6 +2201,7 @@ class UpdaterBindings {
   /// as having been launched successfully.  We don't currently do anything
   /// with this information, but it could be used to record a point at which
   /// we will not roll back from.
+  ///
   /// This is not currently wired up to be called from the Engine.  It's unclear
   /// where best to connect it.  Expo waits 5 seconds after the app launches
   /// and then marks the launch as successful.  We could do something similar.

shorebird_code_push/lib/src/shorebird_code_push.dart

@@ -22,8 +22,21 @@ class ShorebirdCodePush {
 
   /// The version of the currently-installed patch. Null if no patch is
   /// installed (i.e., the app is running the release version).
-  Future<int?> currentPatchVersion() {
-    return _runInIsolate((updater) => updater.currentPatchNumber());
+  Future<int?> currentPatchNumber() {
+    return _runInIsolate((updater) {
+      final patchNumber = updater.currentPatchNumber();
+      return patchNumber == 0 ? null : patchNumber;
+    });
+  }
+
+  /// The version of the patch that will be run on the next app launch. If no
+  /// new patch has been downloaded, this will be the same as
+  /// [currentPatchNumber].
+  Future<int?> nextPatchNumber() {
+    return _runInIsolate((updater) {
+      final patchNumber = updater.nextPatchNumber();
+      return patchNumber == 0 ? null : patchNumber;
+    });
   }
 
   /// Creates an [Updater] in a separate isolate and runs the given function.

shorebird_code_push/lib/src/updater.dart

@@ -18,11 +18,9 @@ class Updater {
   static late UpdaterBindings bindings;
 
   /// The currently active patch number.
-  // TODO(bryanoltman): this will return the current number + 1 if an update is
-  // available. It should instead always return the current patch version.
   int currentPatchNumber() {
     try {
-      return bindings.shorebird_next_boot_patch_number();
+      return bindings.shorebird_current_boot_patch_number();
     } catch (e) {
       return 0;
     }
@@ -36,4 +34,14 @@ class Updater {
       return false;
     }
   }
+
+  /// The next patch number that will be loaded. Will be the same as
+  /// currentPatchNumber if no new patch is available.
+  int nextPatchNumber() {
+    try {
+      return bindings.shorebird_next_boot_patch_number();
+    } catch (e) {
+      return 0;
+    }
+  }
 }