Merge pull request #46 from sjvrensburg/macos-prep

macOS compatibility: native library resolution and config paths

Author: sjvrensburg

CLAUDE.md

@@ -138,7 +138,7 @@ Four SkSL shaders compiled at startup via `SKRuntimeEffect.CreateColorFilter()`.
 
 ## Configuration
 
-Config: `~/.config/railreader2/config.json` (Linux) or `%APPDATA%\railreader2\config.json` (Windows). Auto-created with defaults. Editable live via Settings panel. See `Services/AppConfig.cs` for all fields and defaults.
+Config: `~/.config/railreader2/config.json` (Linux), `%APPDATA%\railreader2\config.json` (Windows), or `~/Library/Application Support/railreader2/config.json` (macOS). Auto-created with defaults. Editable live via Settings panel. See `Services/AppConfig.cs` for all fields and defaults.
 
 Key fields: `rail_zoom_threshold`, `snap_duration_ms`, `scroll_speed_start/max`, `scroll_ramp_time`, `analysis_lookahead_pages`, `ui_font_scale`, `colour_effect/intensity`, `motion_blur/intensity`, `pixel_snapping`, `line_focus_blur/intensity`, `line_highlight_tint/opacity`, `auto_scroll_line_pause_ms/block_pause_ms`, `jump_percentage`, `dark_mode`, `navigable_classes[]`, `recent_files[]`.
 
@@ -148,6 +148,8 @@ Key fields: `rail_zoom_threshold`, `snap_duration_ms`, `scroll_speed_start/max`,
 
 - ONNX model outputs `[N, 7]` tensors with reading order as the 7th column (Global Pointer Mechanism)
 - `PdfOutlineExtractor` uses direct PDFium P/Invoke (`FPDF_*`/`FPDFBookmark_*`) since PDFtoImage doesn't expose bookmarks
+- `PdfiumResolver.Initialize()` must be called before any PDFium P/Invoke — registers a `DllImportResolver` that maps "pdfium" to the correct platform-specific native library (pdfium.dll / libpdfium.so / libpdfium.dylib). Called in all entry points (GUI, CLI, Agent)
+- ONNX runtime pre-loading in `LayoutAnalyzer` static constructor handles Linux (.so) and macOS (.dylib); Windows uses OnnxRuntime's own resolver
 - SkiaSharp 3.x explicitly overrides Avalonia 11's bundled 2.88 — required for `SKRuntimeEffect.CreateColorFilter()`
 - TODO.md and DISTRIBUTION.md are legacy Rust files — disregard them
 - Without the ONNX model, layout falls back to simple horizontal strip detection

src/RailReader.Agent/Program.cs

@@ -6,6 +6,8 @@
 using RailReader.Core.Services;
 using RailReader.Agent;
 
+PdfiumResolver.Initialize();
+
 // --- Check for --capture-screenshots mode ---
 if (args.Length >= 1 && args[0] == "--capture-screenshots")
 {

src/RailReader.Cli/Program.cs

@@ -2,6 +2,9 @@
 using RailReader.Cli;
 using RailReader.Cli.Commands;
 using RailReader.Cli.Output;
+using RailReader.Core.Services;
+
+PdfiumResolver.Initialize();
 
 var jsonOption = new Option<bool>("--json") { Description = "Output in JSON format for machine consumption", Recursive = true };
 

src/RailReader.Core/Services/AppConfig.cs

@@ -48,9 +48,15 @@ public static string ConfigDir
     {
         get
         {
-            var baseDir = OperatingSystem.IsWindows()
-                ? Environment.GetFolderPath(Environment.SpecialFolder.ApplicationData)
-                : Path.Combine(Environment.GetFolderPath(Environment.SpecialFolder.UserProfile), ".config");
+            string baseDir;
+            if (OperatingSystem.IsWindows())
+                baseDir = Environment.GetFolderPath(Environment.SpecialFolder.ApplicationData);
+            else if (OperatingSystem.IsMacOS())
+                baseDir = Path.Combine(Environment.GetFolderPath(Environment.SpecialFolder.UserProfile),
+                    "Library", "Application Support");
+            else
+                baseDir = Path.Combine(Environment.GetFolderPath(Environment.SpecialFolder.UserProfile), ".config");
+
             var dir = Path.Combine(baseDir, "railreader2");
             Directory.CreateDirectory(dir);
             return dir;

src/RailReader.Core/Services/LayoutAnalyzer.cs

@@ -17,15 +17,29 @@ static LayoutAnalyzer()
         // P/Invoke inside OnnxRuntime finds it already loaded — no resolver conflict.
         // (SetDllImportResolver can only be called once per assembly and OnnxRuntime
         // registers its own, so we must not use it.)
-        if (!RuntimeInformation.IsOSPlatform(OSPlatform.Linux)) return;
+        if (RuntimeInformation.IsOSPlatform(OSPlatform.Windows)) return;
 
+        // Platform-specific library name and fallback RIDs
+        string ext, fallbackRid;
+        if (RuntimeInformation.IsOSPlatform(OSPlatform.OSX))
+        {
+            ext = ".dylib";
+            fallbackRid = "osx-arm64";
+        }
+        else
+        {
+            ext = ".so";
+            fallbackRid = "linux-x64";
+        }
+
+        string libName = $"libonnxruntime{ext}";
         string[] candidates =
         [
             Path.Combine(AppContext.BaseDirectory,
-                "runtimes", RuntimeInformation.RuntimeIdentifier, "native", "libonnxruntime.so"),
+                "runtimes", RuntimeInformation.RuntimeIdentifier, "native", libName),
             Path.Combine(AppContext.BaseDirectory,
-                "runtimes", "linux-x64", "native", "libonnxruntime.so"),
-            Path.Combine(AppContext.BaseDirectory, "libonnxruntime.so"),
+                "runtimes", fallbackRid, "native", libName),
+            Path.Combine(AppContext.BaseDirectory, libName),
         ];
 
         foreach (var path in candidates)

src/RailReader.Core/Services/PdfiumResolver.cs

@@ -0,0 +1,74 @@
+using System.Reflection;
+using System.Runtime.InteropServices;
+
+namespace RailReader.Core.Services;
+
+/// <summary>
+/// Registers a DllImport resolver for the "pdfium" native library.
+/// On Linux/macOS the NuGet package ships as libpdfium.so/.dylib in
+/// runtimes/{rid}/native/. .NET's default probing normally finds it
+/// (tries lib prefix + platform extension), but this resolver provides
+/// an explicit fallback to guarantee resolution on all platforms.
+///
+/// Call <see cref="Initialize"/> once at startup, before any P/Invoke
+/// into PDFium (PdfOutlineExtractor, PdfTextService).
+/// PDFtoImage must be referenced so the native asset is deployed.
+/// </summary>
+public static class PdfiumResolver
+{
+    private static bool s_initialized;
+
+    public static void Initialize()
+    {
+        if (s_initialized) return;
+        s_initialized = true;
+
+        NativeLibrary.SetDllImportResolver(
+            typeof(PdfiumResolver).Assembly,
+            ResolvePdfium);
+    }
+
+    private static IntPtr ResolvePdfium(string libraryName, Assembly assembly, DllImportSearchPath? searchPath)
+    {
+        if (libraryName != "pdfium")
+            return IntPtr.Zero; // fall back to default resolution
+
+        // Try default probing first (handles most cases)
+        if (NativeLibrary.TryLoad(libraryName, assembly, searchPath, out var handle))
+            return handle;
+
+        // Explicit platform-specific fallback
+        string ext, prefix;
+        if (RuntimeInformation.IsOSPlatform(OSPlatform.Windows))
+        {
+            ext = ".dll";
+            prefix = "";
+        }
+        else if (RuntimeInformation.IsOSPlatform(OSPlatform.OSX))
+        {
+            ext = ".dylib";
+            prefix = "lib";
+        }
+        else
+        {
+            ext = ".so";
+            prefix = "lib";
+        }
+
+        string libFile = $"{prefix}pdfium{ext}";
+        string[] candidates =
+        [
+            Path.Combine(AppContext.BaseDirectory,
+                "runtimes", RuntimeInformation.RuntimeIdentifier, "native", libFile),
+            Path.Combine(AppContext.BaseDirectory, libFile),
+        ];
+
+        foreach (var path in candidates)
+        {
+            if (File.Exists(path) && NativeLibrary.TryLoad(path, out handle))
+                return handle;
+        }
+
+        return IntPtr.Zero;
+    }
+}

src/RailReader2/Program.cs

@@ -1,4 +1,5 @@
 using Avalonia;
+using RailReader.Core.Services;
 
 namespace RailReader2;
 
@@ -7,6 +8,7 @@ internal sealed class Program
     [STAThread]
     public static void Main(string[] args)
     {
+        PdfiumResolver.Initialize();
         BuildAvaloniaApp()
             .StartWithClassicDesktopLifetime(args);
     }