feat: new SceneBuildIndex sample

Author: sator-imaging

Sample/ScenesInBuild.cs renamed to Sample/SceneBuildIndex.cs

@@ -1,8 +1,9 @@
 // NOTE: to avoid error until first source generation happens.
-public enum ScenesInBuild
+public enum SceneBuildIndex
 {
     NotInitialized = -9999,
     _,
     ToInitializeEnumValues,
     SeeAlternativeSourceGeneratorSampleFolder,
+
 }

Sample/ScenesInBuild.cs.meta renamed to Sample/SceneBuildIndex.cs.meta

@@ -0,0 +1,161 @@
+using System.Collections.Generic;
+using System.IO;
+using System.Text;
+using System.Text.RegularExpressions;
+
+#if UNITY_EDITOR
+using UnityEditor;
+using UnityEditor.Build;
+using UnityEditor.Build.Reporting;
+#endif
+
+namespace SatorImaging.UnitySourceGenerator
+{
+    // HOW TO USE: Add the following attribute to *target* class.
+    //             enum, ScenesInBuild will be generated in the target class namespace.
+    //[UnitySourceGenerator(typeof(SceneBuildIndexEnumGenerator))]
+    public class SceneBuildIndexGenerator
+
+#if UNITY_EDITOR
+        // NOTE: class definition is required to avoid build error due to referencing from USG attributes.
+        //       (or exclude [UnitySourceGenerator(typeof(...))] attributes from build)
+        : IPreprocessBuildWithReport
+#endif
+
+    {
+
+#if UNITY_EDITOR   // USG: class definition is required to avoid build error but methods are not.
+#pragma warning disable IDE0051
+
+        static string OutputFileName() => "Enum.cs";  // -> Test.<ClassName>.g.cs
+
+
+        const string ENUM_NAME = nameof(SceneBuildIndex);
+        readonly static Regex RE_REMOVE_INVALID = new Regex(@"[^A-Za-z_0-9]+", RegexOptions.Compiled);
+
+        static bool Emit(USGContext context, StringBuilder sb)
+        {
+            // code generation
+            sb.Append($@"
+namespace {context.TargetClass.Namespace}
+{{
+    public enum {ENUM_NAME}
+    {{
+");
+            /*  enum  ================================================================ */
+            sb.IndentLevel(2);
+
+            var scenePathList = new List<string>();
+            var sceneNameList = new List<string>();
+            for (int i = 0; i < UnityEditor.EditorBuildSettings.scenes.Length; i++)
+            {
+                var scene = UnityEditor.EditorBuildSettings.scenes[i];  //SceneManager.GetSceneAt(i);
+                scenePathList.Add(scene.path);
+                sceneNameList.Add(Path.GetFileNameWithoutExtension(scene.path));
+
+                var name = RE_REMOVE_INVALID.Replace(Path.GetFileNameWithoutExtension(scene.path), "_");
+                sb.IndentLine($"{name} = {i},");
+            }
+
+            //----------------------------------------------------------------------
+            sb.Append($@"
+    }}
+
+    public static class {ENUM_NAME}Resolver
+    {{
+        readonly static string[] Paths = new string[]
+        {{
+");
+            /*  paths  ================================================================ */
+            sb.IndentLevel(3);
+            foreach (var path in scenePathList)
+            {
+                sb.IndentLine($"\"{path}\",");
+            }
+            //----------------------------------------------------------------------
+            sb.Append($@"
+        }};
+
+        readonly static string[] Names = new string[]
+        {{
+");
+            /*  names  ================================================================ */
+            sb.IndentLevel(3);
+            foreach (var name in sceneNameList)
+            {
+                sb.IndentLine($"\"{name}\",");
+            }
+            //----------------------------------------------------------------------
+            sb.Append($@"
+        }};
+
+        public static {ENUM_NAME} GetByName(string name)
+        {{
+            int found = -1;
+            for (int i = 0; i < Names.Length; i++)
+            {{
+                if (Names[i] == name)
+                {{
+                    if (found < 0)
+                        found = i;
+                    else
+                        throw new System.Exception($""multiple scenes are found: '{{name}}'"");
+                }}
+            }}
+            if (found < 0)
+                throw new System.Exception($""scene file '{{name}}' is not registered in build settings."");
+            return ({ENUM_NAME})found;
+        }}
+
+        public static System.Collections.Generic.List<{ENUM_NAME}> GetListByPrefix(string fileNamePrefix)
+        {{
+            var ret = new System.Collections.Generic.List<{ENUM_NAME}>(capacity: Names.Length);
+            for (int i = 0; i < Names.Length; i++)
+            {{
+                if (Names[i].StartsWith(fileNamePrefix, System.StringComparison.Ordinal))
+                {{
+                    ret.Add(({ENUM_NAME})i);
+                }}
+            }}
+            return ret;
+        }}
+
+        ///<summary>Path must be started with 'Assets/'.</summary>
+        public static System.Collections.Generic.List<{ENUM_NAME}> GetListByPath(string assetsPath)
+        {{
+            var ret = new System.Collections.Generic.List<{ENUM_NAME}>(capacity: Paths.Length);
+            for (int i = 0; i < Paths.Length; i++)
+            {{
+                if (Paths[i].StartsWith(assetsPath, System.StringComparison.Ordinal))
+                {{
+                    ret.Add(({ENUM_NAME})i);
+                }}
+            }}
+            return ret;
+        }}
+    }}
+}}
+");
+            return true;
+        }
+
+
+        /*  events  ================================================================ */
+
+        public int callbackOrder => 0;
+        public void OnPreprocessBuild(BuildReport report) => ForceUpdate();
+
+        static void ForceUpdate() => USGUtility.ForceGenerateByType(typeof(SceneBuildIndexGenerator), false);
+
+        [InitializeOnLoadMethod]
+        static void RegisterEvent()
+        {
+            EditorBuildSettings.sceneListChanged -= ForceUpdate;
+            EditorBuildSettings.sceneListChanged += ForceUpdate;
+        }
+
+
+#pragma warning restore IDE0051
+#endif
+    }
+}