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327 | -- SPDX-License-Identifier: Apache-2.0
--
-- Copyright (c) 2019 onox <denkpadje@gmail.com>
--
-- Licensed under the Apache License, Version 2.0 (the "License");
-- you may not use this file except in compliance with the License.
-- You may obtain a copy of the License at
--
-- http://www.apache.org/licenses/LICENSE-2.0
--
-- Unless required by applicable law or agreed to in writing, software
-- distributed under the License is distributed on an "AS IS" BASIS,
-- WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-- See the License for the specific language governing permissions and
-- limitations under the License.
with System;
with Ada.Streams;
with Ada.Unchecked_Conversion;
package body Inotify is
use type GNAT.OS_Lib.File_Descriptor;
overriding procedure Initialize (Object : in out Instance) is
function Inotify_Init return GNAT.OS_Lib.File_Descriptor
with Import, Convention => C, External_Name => "inotify_init";
begin
Object.Instance := Inotify_Init;
if Object.Instance = GNAT.OS_Lib.Invalid_FD then
raise Program_Error;
end if;
end Initialize;
overriding procedure Finalize (Object : in out Instance) is
Status : Boolean;
begin
if Object.Instance /= GNAT.OS_Lib.Invalid_FD then
GNAT.OS_Lib.Close (Object.Instance, Status);
Object.Instance := GNAT.OS_Lib.Invalid_FD;
if not Status then
raise Program_Error;
end if;
end if;
end Finalize;
function File_Descriptor (Object : Instance) return Integer is (Integer (Object.Instance));
use type Interfaces.C.int;
function Add_Watch
(Object : in out Instance;
Path : String;
Mask : Watch_Bits := All_Events) return Watch
is
function Inotify_Add_Watch
(Instance : GNAT.OS_Lib.File_Descriptor;
Path : Interfaces.C.char_array;
Mask : Interfaces.C.unsigned) return Interfaces.C.int
with Import, Convention => C, External_Name => "inotify_add_watch";
function Convert is new Ada.Unchecked_Conversion
(Source => Watch_Bits, Target => Interfaces.C.unsigned);
Result : constant Interfaces.C.int := Inotify_Add_Watch
(Object.Instance, Interfaces.C.To_C (Path), Convert (Mask));
begin
if Result = -1 then
raise Program_Error;
end if;
Object.Watches.Include (Result, Path);
return (Watch => Result);
end Add_Watch;
procedure Add_Watch
(Object : in out Instance;
Path : String;
Mask : Watch_Bits := All_Events)
is
Result : constant Watch := Instance'Class (Object).Add_Watch (Path, Mask);
begin
pragma Assert (Result.Watch /= -1);
end Add_Watch;
procedure Remove_Watch (Object : in out Instance; Subject : Watch) is
function Inotify_Remove_Watch
(Instance : GNAT.OS_Lib.File_Descriptor;
Watch : Interfaces.C.int) return Interfaces.C.int
with Import, Convention => C, External_Name => "inotify_rm_watch";
begin
-- Procedure Process_Events might read multiple events for a specific
-- watch and the callback for the first event may immediately try to
-- remove the watch
if Object.Defer_Remove then
if not Object.Pending_Removals.Contains (Subject) then
Object.Pending_Removals.Append (Subject);
end if;
return;
end if;
if Inotify_Remove_Watch (Object.Instance, Subject.Watch) = -1 then
raise Program_Error;
end if;
Object.Watches.Delete (Subject.Watch);
end Remove_Watch;
function Has_Watches (Object : in out Instance) return Boolean is
(not Object.Watches.Is_Empty);
function Name (Object : Instance; Subject : Watch) return String is
(Object.Watches.Element (Subject.Watch));
-----------------------------------------------------------------------------
type Inotify_Event is record
Watch : Interfaces.C.int; -- -1 if event queue has overflowed
Mask : Interfaces.C.unsigned;
Cookie : Interfaces.C.unsigned;
Length : Interfaces.C.unsigned;
end record
with Convention => C,
Alignment => 4;
type Event_Bits is record
Event : Event_Kind;
Queue_Overflowed : Boolean := False;
Ignored : Boolean := False;
Is_Directory : Boolean := False;
end record;
for Event_Bits use record
Event at 0 range 0 .. 13;
Queue_Overflowed at 0 range 14 .. 14;
Ignored at 0 range 15 .. 15;
Is_Directory at 0 range 30 .. 30;
end record;
for Event_Bits'Size use Interfaces.C.unsigned'Size;
for Event_Bits'Alignment use Interfaces.C.unsigned'Alignment;
procedure Process_Events
(Object : in out Instance;
Handle : not null access procedure
(Subject : Watch;
Event : Event_Kind;
Is_Directory : Boolean;
Name : String);
Move_Handle : not null access procedure
(Subject : Watch;
Is_Directory : Boolean;
From, To : String))
is
use Ada.Streams;
function Convert is new Ada.Unchecked_Conversion
(Source => Stream_Element_Array, Target => Inotify_Event);
function Convert is new Ada.Unchecked_Conversion
(Source => Interfaces.C.unsigned, Target => Event_Bits);
Event_In_Bytes : constant Stream_Element_Offset
:= Inotify_Event'Size / System.Storage_Unit;
Length : Stream_Element_Offset;
Buffer : Stream_Element_Array (1 .. 4096)
with Alignment => 4;
function Find_Move (Cookie : Interfaces.C.unsigned) return Move_Vectors.Cursor is
Cursor : Move_Vectors.Cursor := Move_Vectors.No_Element;
procedure Reverse_Iterate (Position : Move_Vectors.Cursor) is
use type Interfaces.C.unsigned;
begin
if Cookie = Object.Moves (Position).Key then
Cursor := Position;
end if;
end Reverse_Iterate;
begin
Object.Moves.Reverse_Iterate (Reverse_Iterate'Access);
return Cursor;
end Find_Move;
use type Ada.Containers.Count_Type;
begin
if Object.Watches.Is_Empty then
return;
end if;
Length := Stream_Element_Offset (GNAT.OS_Lib.Read
(Object.Instance, Buffer'Address, Buffer'Length));
if Length = -1 then
raise Read_Error;
end if;
if Length = 0 then
return;
end if;
declare
Index : Stream_Element_Offset := Buffer'First;
begin
Object.Defer_Remove := True;
while Index < Buffer'First + Length loop
declare
Event : constant Inotify_Event
:= Convert (Buffer (Index .. Index + Event_In_Bytes - 1));
Mask : constant Event_Bits := Convert (Event.Mask);
Name_Length : constant Stream_Element_Offset
:= Stream_Element_Offset (Event.Length);
begin
if Mask.Queue_Overflowed then
raise Queue_Overflow_Error;
end if;
pragma Assert (Event.Watch /= -1);
if Mask.Ignored then
Object.Watches.Exclude (Event.Watch);
else
declare
Directory : constant String := Object.Watches.Element (Event.Watch);
begin
if Name_Length > 0 then
declare
subtype Name_Array is Interfaces.C.char_array
(1 .. Interfaces.C.size_t (Event.Length));
subtype Name_Buffer is Stream_Element_Array
(1 .. Name_Length);
function Convert is new Ada.Unchecked_Conversion
(Source => Name_Buffer, Target => Name_Array);
Name_Index : constant Stream_Element_Offset
:= Index + Event_In_Bytes;
Name : constant String := Interfaces.C.To_Ada (Convert
(Buffer (Name_Index .. Name_Index + Name_Length - 1)));
begin
Handle
((Watch => Event.Watch), Mask.Event,
Mask.Is_Directory, Directory & "/" & Name);
case Mask.Event is
when Moved_From =>
if Object.Moves.Length = Object.Moves.Capacity then
Object.Moves.Delete_First;
end if;
Object.Moves.Append ((Event.Cookie,
(From => SU.To_Unbounded_String (Directory & "/" & Name),
To => <>)));
-- If inode is moved to outside watched directory,
-- then there will never be a Moved_To or Moved_Self
-- if instance is not recursive
when Moved_To =>
declare
Cursor : Move_Vectors.Cursor := Find_Move (Event.Cookie);
use type Move_Vectors.Cursor;
begin
if Cursor /= Move_Vectors.No_Element then
-- It's a rename
Move_Handle
(Subject => (Watch => Event.Watch),
Is_Directory => Mask.Is_Directory,
From => SU.To_String
(Object.Moves (Cursor).Value.From),
To => Directory & "/" & Name);
Object.Moves.Delete (Cursor);
else
Move_Handle
(Subject => (Watch => Event.Watch),
Is_Directory => Mask.Is_Directory,
From => "",
To => Directory & "/" & Name);
end if;
end;
when others =>
null;
end case;
end;
else
Handle
((Watch => Event.Watch), Mask.Event,
Mask.Is_Directory, Directory);
end if;
end;
end if;
Index := Index + Event_In_Bytes + Name_Length;
end;
end loop;
Object.Defer_Remove := False;
-- Remove pending removals of watches after having processed
-- all events
for Watch of Object.Pending_Removals loop
Object.Remove_Watch (Watch);
end loop;
Object.Pending_Removals.Clear;
end;
end Process_Events;
procedure Process_Events
(Object : in out Instance;
Handle : not null access procedure
(Subject : Watch;
Event : Event_Kind;
Is_Directory : Boolean;
Name : String))
is
procedure Move_Handle
(Subject : Watch;
Is_Directory : Boolean;
From, To : String) is null;
begin
Object.Process_Events (Handle, Move_Handle'Access);
end Process_Events;
end Inotify;
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