refactor(git_types): use enums (#53)

Use Dart's new feature "Enhanced enums with members".

lib/src/config.dart

@@ -99,7 +99,7 @@ class Config with IterableMixin<ConfigEntry> {
     final name = entryPointer.ref.name.cast<Utf8>().toDartString();
     final value = entryPointer.ref.value.cast<Utf8>().toDartString();
     final includeDepth = entryPointer.ref.include_depth;
-    final level = GitConfigLevel.values.singleWhere(
+    final level = GitConfigLevel.values.firstWhere(
       (e) => entryPointer.ref.level == e.value,
     );
 
@@ -261,7 +261,7 @@ class _ConfigIterator implements Iterator<ConfigEntry> {
         final name = entry.value.ref.name.cast<Utf8>().toDartString();
         final value = entry.value.ref.value.cast<Utf8>().toDartString();
         final includeDepth = entry.value.ref.include_depth;
-        final level = GitConfigLevel.values.singleWhere(
+        final level = GitConfigLevel.values.firstWhere(
           (e) => entry.value.ref.level == e.value,
         );
 

lib/src/diff.dart

@@ -481,7 +481,7 @@ class DiffDelta {
 
   /// Type of change.
   GitDelta get status {
-    return GitDelta.values.singleWhere(
+    return GitDelta.values.firstWhere(
       (e) => _diffDeltaPointer.ref.status == e.value,
     );
   }
@@ -552,7 +552,7 @@ class DiffFile {
 
   /// One of the [GitFilemode] values.
   GitFilemode get mode {
-    return GitFilemode.values.singleWhere((e) => _diffFile.mode == e.value);
+    return GitFilemode.values.firstWhere((e) => _diffFile.mode == e.value);
   }
 
   @override

lib/src/index.dart

@@ -349,7 +349,7 @@ class IndexEntry {
 
   /// UNIX file attributes of a index entry.
   GitFilemode get mode {
-    return GitFilemode.values.singleWhere(
+    return GitFilemode.values.firstWhere(
       (mode) => _indexEntryPointer.ref.mode == mode.value,
     );
   }

lib/src/merge.dart

@@ -69,7 +69,7 @@ class Merge {
     final result = GitMergeAnalysis.values
         .where((e) => analysisInt[0] & e.value == e.value)
         .toSet();
-    final preference = GitMergePreference.values.singleWhere(
+    final preference = GitMergePreference.values.firstWhere(
       (e) => analysisInt[1] == e.value,
     );
 

lib/src/odb.dart

@@ -125,7 +125,7 @@ class OdbObject {
   /// Type of an ODB object.
   GitObject get type {
     final typeInt = bindings.objectType(_odbObjectPointer);
-    return GitObject.values.singleWhere((e) => typeInt == e.value);
+    return GitObject.values.firstWhere((e) => typeInt == e.value);
   }
 
   /// Uncompressed, raw data as read from the ODB, without the leading header.

lib/src/patch.dart

@@ -220,7 +220,7 @@ class Patch {
         );
         lines.add(
           DiffLine._(
-            origin: GitDiffLine.values.singleWhere(
+            origin: GitDiffLine.values.firstWhere(
               (e) => linePointer.ref.origin == e.value,
             ),
             oldLineNumber: linePointer.ref.old_lineno,

lib/src/rebase.dart

@@ -158,7 +158,7 @@ class RebaseOperation {
 
   /// Type of rebase operation.
   GitRebaseOperation get type {
-    return GitRebaseOperation.values.singleWhere(
+    return GitRebaseOperation.values.firstWhere(
       (e) => _rebaseOperationPointer.ref.type == e.value,
     );
   }

lib/src/repository.dart

@@ -330,7 +330,7 @@ class Repository {
   /// cherry-pick, etc) is in progress.
   GitRepositoryState get state {
     final stateInt = bindings.state(_repoPointer);
-    return GitRepositoryState.values.singleWhere(
+    return GitRepositoryState.values.firstWhere(
       (state) => stateInt == state.value,
     );
   }

lib/src/submodule.dart

@@ -229,7 +229,7 @@ class Submodule {
   /// Ignore rule that will be used for the submodule.
   GitSubmoduleIgnore get ignore {
     final ruleInt = bindings.ignore(_submodulePointer);
-    return GitSubmoduleIgnore.values.singleWhere((e) => ruleInt == e.value);
+    return GitSubmoduleIgnore.values.firstWhere((e) => ruleInt == e.value);
   }
 
   /// Sets the ignore rule for the submodule in the configuration.
@@ -245,7 +245,7 @@ class Submodule {
   /// This value controls the behavior of the `git submodule update` command.
   GitSubmoduleUpdate get updateRule {
     final ruleInt = bindings.updateRule(_submodulePointer);
-    return GitSubmoduleUpdate.values.singleWhere((e) => ruleInt == e.value);
+    return GitSubmoduleUpdate.values.firstWhere((e) => ruleInt == e.value);
   }
 
   /// Sets the update rule for the submodule in the configuration.

lib/src/tree.dart

@@ -137,7 +137,7 @@ class TreeEntry {
   /// UNIX file attributes of a tree entry.
   GitFilemode get filemode {
     final modeInt = bindings.entryFilemode(_treeEntryPointer);
-    return GitFilemode.values.singleWhere((mode) => modeInt == mode.value);
+    return GitFilemode.values.firstWhere((mode) => modeInt == mode.value);
   }
 
   /// Releases memory allocated for tree entry object.

test/diff_test.dart

@@ -471,13 +471,13 @@ index e69de29..c217c63 100644
         newTree: Tree.lookup(repo: repo, oid: repo.index.writeTree()),
       );
       expect(
-        diff.deltas.singleWhere((e) => e.newFile.path == 'staged_new').status,
+        diff.deltas.firstWhere((e) => e.newFile.path == 'staged_new').status,
         GitDelta.added,
       );
 
       diff.findSimilar();
       expect(
-        diff.deltas.singleWhere((e) => e.newFile.path == 'staged_new').status,
+        diff.deltas.firstWhere((e) => e.newFile.path == 'staged_new').status,
         GitDelta.renamed,
       );
     });