------------------------------------------------------------------------------ -- -- -- GNAT RUN-TIME COMPONENTS -- -- -- -- S Y S T E M . M M A P . O S _ I N T E R F A C E -- -- -- -- B o d y -- -- -- -- Copyright (C) 2007-2024, AdaCore -- -- -- -- This library is free software; you can redistribute it and/or modify it -- -- under terms of the GNU General Public License as published by the Free -- -- Software Foundation; either version 3, or (at your option) any later -- -- version. This library is distributed in the hope that it will be useful, -- -- but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHAN- -- -- TABILITY or FITNESS FOR A PARTICULAR PURPOSE. -- -- -- -- As a special exception under Section 7 of GPL version 3, you are granted -- -- additional permissions described in the GCC Runtime Library Exception, -- -- version 3.1, as published by the Free Software Foundation. -- -- -- -- You should have received a copy of the GNU General Public License and -- -- a copy of the GCC Runtime Library Exception along with this program; -- -- see the files COPYING3 and COPYING.RUNTIME respectively. If not, see -- -- . -- -- -- -- GNAT was originally developed by the GNAT team at New York University. -- -- Extensive contributions were provided by Ada Core Technologies Inc. -- -- -- ------------------------------------------------------------------------------ with Ada.IO_Exceptions; with System.Strings; use System.Strings; with System.OS_Lib; pragma Unreferenced (System.OS_Lib); -- Only used to generate same runtime dependencies and same binder file on -- GNU/Linux and Windows. package body System.Mmap.OS_Interface is use Win; function Align (Addr : File_Size) return File_Size; -- Align some offset/length to the lowest page boundary function Open_Common (Filename : String; Use_Mmap_If_Available : Boolean; Write : Boolean) return System_File; function From_UTF8 (Path : String) return Wide_String; -- Convert from UTF-8 to Wide_String --------------- -- From_UTF8 -- --------------- function From_UTF8 (Path : String) return Wide_String is function MultiByteToWideChar (Codepage : Interfaces.C.unsigned; Flags : Interfaces.C.unsigned; Mbstr : Address; Mb : Natural; Wcstr : Address; Wc : Natural) return Integer; pragma Import (Stdcall, MultiByteToWideChar, "MultiByteToWideChar"); Current_Codepage : Interfaces.C.unsigned; pragma Import (C, Current_Codepage, "__gnat_current_codepage"); Len : Natural; begin -- Compute length of the result Len := MultiByteToWideChar (Current_Codepage, 0, Path'Address, Path'Length, Null_Address, 0); if Len = 0 then raise Constraint_Error; end if; declare -- Declare result Res : Wide_String (1 .. Len); begin -- And compute it Len := MultiByteToWideChar (Current_Codepage, 0, Path'Address, Path'Length, Res'Address, Len); if Len = 0 then raise Constraint_Error; end if; return Res; end; end From_UTF8; ----------------- -- Open_Common -- ----------------- function Open_Common (Filename : String; Use_Mmap_If_Available : Boolean; Write : Boolean) return System_File is dwDesiredAccess, dwShareMode : DWORD; PageFlags : DWORD; W_Filename : constant Wide_String := From_UTF8 (Filename) & Wide_Character'Val (0); File_Handle, Mapping_Handle : HANDLE; SizeH : aliased DWORD; Size : File_Size; begin if Write then dwDesiredAccess := GENERIC_READ + GENERIC_WRITE; dwShareMode := 0; PageFlags := Win.PAGE_READWRITE; else dwDesiredAccess := GENERIC_READ; dwShareMode := Win.FILE_SHARE_READ; PageFlags := Win.PAGE_READONLY; end if; -- Actually open the file File_Handle := CreateFile (W_Filename'Address, dwDesiredAccess, dwShareMode, null, OPEN_EXISTING, Win.FILE_ATTRIBUTE_NORMAL, 0); if File_Handle = Win.INVALID_HANDLE_VALUE then return Invalid_System_File; end if; -- Compute its size Size := File_Size (Win.GetFileSize (File_Handle, SizeH'Access)); if Size = Win.INVALID_FILE_SIZE then return Invalid_System_File; end if; if SizeH /= 0 and then File_Size'Size > 32 then Size := Size + (File_Size (SizeH) * 2 ** 32); end if; -- Then create a mapping object, if needed. On Win32, file memory -- mapping is always available. if Use_Mmap_If_Available then Mapping_Handle := Win.CreateFileMapping (File_Handle, null, PageFlags, 0, DWORD (Size), Standard.System.Null_Address); else Mapping_Handle := Win.INVALID_HANDLE_VALUE; end if; return (Handle => File_Handle, Mapped => Use_Mmap_If_Available, Mapping_Handle => Mapping_Handle, Write => Write, Length => Size); end Open_Common; --------------- -- Open_Read -- --------------- function Open_Read (Filename : String; Use_Mmap_If_Available : Boolean := True) return System_File is begin return Open_Common (Filename, Use_Mmap_If_Available, False); end Open_Read; ---------------- -- Open_Write -- ---------------- function Open_Write (Filename : String; Use_Mmap_If_Available : Boolean := True) return System_File is begin return Open_Common (Filename, Use_Mmap_If_Available, True); end Open_Write; ----------- -- Close -- ----------- procedure Close (File : in out System_File) is Ignored : BOOL; pragma Unreferenced (Ignored); begin Ignored := CloseHandle (File.Mapping_Handle); Ignored := CloseHandle (File.Handle); File.Handle := Win.INVALID_HANDLE_VALUE; File.Mapping_Handle := Win.INVALID_HANDLE_VALUE; end Close; -------------------- -- Read_From_Disk -- -------------------- function Read_From_Disk (File : System_File; Offset, Length : File_Size) return System.Strings.String_Access is Buffer : String_Access := new String (1 .. Integer (Length)); Pos : DWORD; NbRead : aliased DWORD; pragma Unreferenced (Pos); begin Pos := Win.SetFilePointer (File.Handle, LONG (Offset), null, Win.FILE_BEGIN); if Win.ReadFile (File.Handle, Buffer.all'Address, DWORD (Length), NbRead'Unchecked_Access, null) = Win.FALSE then System.Strings.Free (Buffer); raise Ada.IO_Exceptions.Device_Error; end if; return Buffer; end Read_From_Disk; ------------------- -- Write_To_Disk -- ------------------- procedure Write_To_Disk (File : System_File; Offset, Length : File_Size; Buffer : System.Strings.String_Access) is Pos : DWORD; NbWritten : aliased DWORD; pragma Unreferenced (Pos); begin pragma Assert (File.Write); Pos := Win.SetFilePointer (File.Handle, LONG (Offset), null, Win.FILE_BEGIN); if Win.WriteFile (File.Handle, Buffer.all'Address, DWORD (Length), NbWritten'Unchecked_Access, null) = Win.FALSE then raise Ada.IO_Exceptions.Device_Error; end if; end Write_To_Disk; -------------------- -- Create_Mapping -- -------------------- procedure Create_Mapping (File : System_File; Offset, Length : in out File_Size; Mutable : Boolean; Mapping : out System_Mapping) is Flags : DWORD; begin if File.Write then Flags := Win.FILE_MAP_WRITE; elsif Mutable then Flags := Win.FILE_MAP_COPY; else Flags := Win.FILE_MAP_READ; end if; -- Adjust offset and mapping length to account for the required -- alignment of offset on page boundary. declare Queried_Offset : constant File_Size := Offset; begin Offset := Align (Offset); -- First extend the length to compensate the offset shift, then align -- it on the upper page boundary, so that the whole queried area is -- covered. Length := Length + Queried_Offset - Offset; Length := Align (Length + Get_Page_Size - 1); -- But do not exceed the length of the file if Offset + Length > File.Length then Length := File.Length - Offset; end if; end; if Length > File_Size (Integer'Last) then raise Ada.IO_Exceptions.Device_Error; else Mapping := Invalid_System_Mapping; Mapping.Address := Win.MapViewOfFile (File.Mapping_Handle, Flags, 0, DWORD (Offset), SIZE_T (Length)); Mapping.Length := Length; end if; end Create_Mapping; --------------------- -- Dispose_Mapping -- --------------------- procedure Dispose_Mapping (Mapping : in out System_Mapping) is Ignored : BOOL; pragma Unreferenced (Ignored); begin Ignored := Win.UnmapViewOfFile (Mapping.Address); Mapping := Invalid_System_Mapping; end Dispose_Mapping; ------------------- -- Get_Page_Size -- ------------------- function Get_Page_Size return File_Size is SystemInfo : aliased SYSTEM_INFO; begin GetSystemInfo (SystemInfo'Unchecked_Access); return File_Size (SystemInfo.dwAllocationGranularity); end Get_Page_Size; ----------- -- Align -- ----------- function Align (Addr : File_Size) return File_Size is begin return Addr - Addr mod Get_Page_Size; end Align; end System.Mmap.OS_Interface;