Migrate edicon to Ruby Implementation

This pull request introduces a Ruby-based implementation of the previously C-based `edicon.exe`. Opting for a Ruby reimplement over fixing the existing C code will shorten the build times and make maintenance easier, leveraging widely accessible Microsoft documentation.

Reference Information:
The original `edicon.c` contained several issues that are being addressed by this reimplementation:

- `BeginUpdateResource` was incorrectly compared to `INVALID_HANDLE_VALUE`. Proper error checking requires comparison to `NULL`.
- The calculation of `GroupIconSize` was incorrect. It should have been calculated using the size of `IconDirResEntry` multiplied by the number of images, instead of using `IconDirectoryEntry`.
This reimplement ensures that the functionality of `EdIcon` is preserved while simplifying future enhancements and maintenance.

Author: shinokaro

Rakefile

@@ -16,7 +16,7 @@ STUB_DIR   = "share/ocran"
 BUILD_DIR  = "src"
 
 if WINDOWS
-  STUB_NAMES = %w[stub stubw edicon]
+  STUB_NAMES = %w[stub stubw]
   STUB_EXE_EXT = ".exe"
 else
   STUB_NAMES = %w[stub]

lib/ocran/ed_icon.rb

@@ -0,0 +1,157 @@
+# frozen_string_literal: true
+require "fiddle/import"
+require "fiddle/types"
+
+module Ocran
+  # Changes the Icon in a PE executable.
+  module EdIcon
+    extend Fiddle::Importer
+    dlload "kernel32.dll"
+
+    include Fiddle::Win32Types
+    typealias "LPVOID", "void*"
+    typealias "LPCWSTR", "char*"
+
+    module Successive
+      include Enumerable
+
+      def each
+        return to_enum(__method__) unless block_given?
+
+        entry = self
+        while true
+          yield(entry)
+          entry = self.class.new(tail)
+        end
+      end
+
+      def tail
+        to_ptr + self.class.size
+      end
+    end
+
+    # Icon file header
+    IconHeader = struct(
+      [
+        "WORD Reserved",
+        "WORD ResourceType",
+        "WORD ImageCount"
+      ]
+    ).include(Successive)
+
+    icon_info = [
+      "BYTE Width",
+      "BYTE Height",
+      "BYTE Colors",
+      "BYTE Reserved",
+      "WORD Planes",
+      "WORD BitsPerPixel",
+      "DWORD ImageSize"
+    ]
+
+    # Icon File directory entry structure
+    IconDirectoryEntry = struct(icon_info + ["DWORD ImageOffset"]).include(Successive)
+
+    # Group Icon Resource directory entry structure
+    IconDirResEntry = struct(icon_info + ["WORD ResourceID"]).include(Successive)
+
+    class IconFile < IconHeader
+      def initialize(icon_filename)
+        @data = File.binread(icon_filename)
+        super(Fiddle::Pointer.to_ptr(@data))
+
+        entries_end = IconHeader.size + self.ImageCount * IconDirectoryEntry.size
+        if entries_end > @data.bytesize
+          raise "Icon file too small for declared ImageCount"
+        end
+
+        entries.each_with_index do |entry, i|
+          if entry.ImageOffset + entry.ImageSize > @data.bytesize
+            raise "Icon entry #{i} exceeds file bounds"
+          end
+        end
+      end
+
+      def entries
+        IconDirectoryEntry.new(self.tail).take(self.ImageCount)
+      end
+    end
+
+    class GroupIcon < IconHeader
+      attr_reader :size
+
+      def initialize(image_count, resource_type)
+        @size = IconHeader.size + image_count * IconDirResEntry.size
+        super(Fiddle.malloc(@size), Fiddle::RUBY_FREE)
+        self.Reserved = 0
+        self.ResourceType = resource_type
+        self.ImageCount = image_count
+      end
+
+      def entries
+        IconDirResEntry.new(self.tail).take(self.ImageCount)
+      end
+    end
+
+    MAKEINTRESOURCE = -> (i) { Fiddle::Pointer.new(i) }
+    RT_ICON = MAKEINTRESOURCE.(3)
+    RT_GROUP_ICON = MAKEINTRESOURCE.(RT_ICON.to_i + 11)
+
+    MAKELANGID = -> (p, s) { s << 10 | p }
+    LANG_NEUTRAL = 0x00
+    SUBLANG_DEFAULT = 0x01
+    LANGID = MAKELANGID.(LANG_NEUTRAL, SUBLANG_DEFAULT)
+
+    extern "DWORD GetLastError()"
+    extern "HANDLE BeginUpdateResourceW(LPCWSTR, BOOL)"
+    extern "BOOL EndUpdateResourceW(HANDLE, BOOL)"
+    extern "BOOL UpdateResourceW(HANDLE, LPCWSTR, LPCWSTR, WORD, LPVOID, DWORD)"
+
+    class << self
+      def update_icon(executable_filename, icon_filename)
+        update_resource(executable_filename) do |handle|
+          icon_file = IconFile.new(icon_filename)
+          icon_entries = icon_file.entries
+
+          # Create the RT_ICON resources
+          icon_entries.each_with_index do |entry, i|
+            if UpdateResourceW(handle, RT_ICON, 101 + i, LANGID, icon_file.to_i + entry.ImageOffset, entry.ImageSize) == 0
+              raise "failed to UpdateResource(#{GetLastError()})"
+            end
+          end
+
+          # Create the RT_GROUP_ICON structure
+          group_icon = GroupIcon.new(icon_file.ImageCount, icon_file.ResourceType)
+          group_icon.entries.zip(icon_entries).each_with_index do |(res, icon), i|
+            res.Width = icon.Width
+            res.Height = icon.Height
+            res.Colors = icon.Colors
+            res.Reserved = icon.Reserved
+            res.Planes = icon.Planes
+            res.BitsPerPixel = icon.BitsPerPixel
+            res.ImageSize = icon.ImageSize
+            res.ResourceID = 101 + i
+          end
+
+          # Save the RT_GROUP_ICON resource
+          if UpdateResourceW(handle, RT_GROUP_ICON, 100, LANGID, group_icon, group_icon.size) == 0
+            raise "Failed to create group icon(#{GetLastError()})"
+          end
+        end
+      end
+
+      def update_resource(executable_filename)
+        handle = BeginUpdateResourceW(executable_filename.encode("UTF-16LE"), 0)
+        if handle == Fiddle::NULL
+          raise "Failed to BeginUpdateResourceW(#{GetLastError()})"
+        end
+
+        yield(handle)
+
+        if EndUpdateResourceW(handle, 0) == 0
+          raise "Failed to EndUpdateResourceW(#{GetLastError()})"
+        end
+      end
+    end
+  end
+end

lib/ocran/stub_builder.rb

@@ -27,7 +27,6 @@ class StubBuilder
     STUB_PATH = File.expand_path(WINDOWS ? "stub.exe" : "stub", base_dir)
     STUBW_PATH = WINDOWS ? File.expand_path("stubw.exe", base_dir) : nil
     LZMA_PATH = WINDOWS ? File.expand_path("lzma.exe", base_dir) : nil
-    EDICON_PATH = WINDOWS ? File.expand_path("edicon.exe", base_dir) : nil
 
     def self.find_posix_lzma_cmd
       if system("which lzma > /dev/null 2>&1")
@@ -122,7 +121,8 @@ def initialize(path, chdir_before: nil, debug_extract: nil, debug_mode: nil,
 
       # Embed icon resource (Windows only)
       if icon_path && WINDOWS
-        system(EDICON_PATH, stub, icon_path.to_s, exception: true)
+        require_relative "ed_icon"
+        EdIcon.update_icon(stub, icon_path.to_s)
       end
 
       File.open(stub, "ab") do |of|

src/Makefile

@@ -21,7 +21,7 @@ else
   STUB_CFLAGS     := $(CFLAGS) -D_CONSOLE
   STUBW_CFLAGS    := $(CFLAGS)
   SYSTEM_UTILS_SRC := system_utils.c
-  PROG_NAMES      := stub stubw edicon
+  PROG_NAMES      := stub stubw
   RESOURCE_OBJ    := stub.res
 endif
 
@@ -62,13 +62,11 @@ ifeq ($(IS_POSIX),)
 stubw$(EXEEXT): $(COMMON_OBJS) $(WINDOW_OBJS)
 	$(CC) $(LDFLAGS) $(GUI_LDFLAGS) $^ $(LDLIBS) -o $@
 
-edicon$(EXEEXT): edicon.o
-	$(CC) $(LDFLAGS) $^ -o $@
 endif
 
 clean:
 	rm -f $(BINARIES) $(COMMON_OBJS) $(CONSOLE_OBJS) $(WINDOW_OBJS) \
-	      edicon.o $(RESOURCE_OBJ)
+	      $(RESOURCE_OBJ)
 
 install: $(BINARIES)
 	mkdir -p $(BINDIR)