V315-025: Use new LAL's API for preprocessing

Instead of our custom one.

Author: AnthonyLeonardoGracio

source/ada/lsp-ada_handlers-file_readers.adb

@@ -15,12 +15,18 @@
 -- of the license.                                                          --
 ------------------------------------------------------------------------------
 
-with VSS.Strings;       use VSS.Strings;
-with LSP.Ada_Documents; use LSP.Ada_Documents;
-with LSP.Preprocessor;  use LSP.Preprocessor;
+with GNAT.Strings;                 use GNAT.Strings;
+with GNATCOLL.Traces;              use GNATCOLL.Traces;
+with VSS.Strings;                  use VSS.Strings;
+with VSS.Strings.Conversions;
+with LSP.Ada_Documents;            use LSP.Ada_Documents;
+with Libadalang.Preprocessing;     use Libadalang.Preprocessing;
+with Langkit_Support.File_Readers; use Langkit_Support.File_Readers;
 
 package body LSP.Ada_Handlers.File_Readers is
 
+   Me : constant Trace_Handle := Create ("ALS.FILE_READERS");
+
    ----------
    -- Read --
    ----------
@@ -34,22 +40,65 @@ package body LSP.Ada_Handlers.File_Readers is
       Diagnostics : in out
         Langkit_Support.Diagnostics.Diagnostics_Vectors.Vector)
    is
-      Doc : Document_Access;
+      Doc    : Document_Access;
+      Source : Preprocessed_Source := Preprocessed_Source'
+        (Buffer => null, Last => 0);
+      Buffer : GNAT.Strings.String_Access;
    begin
       --  First check if the file is an open document
       Doc := Self.Handler.Get_Open_Document
         (URI   => LSP.Types.File_To_URI (Filename),
          Force => False);
 
+      --  Preprocess the document's contents if open, or the file contents if
+      --  not.
       if Doc /= null then
-         --  There is a document - we can get this and preprocess
-         Contents := Preprocess_Buffer (Buffer => Doc.Text);
-
+         Buffer := new String'
+           (VSS.Strings.Conversions.To_UTF_8_String (Doc.Text));
       else
-         --  No open document: preprocess from the file
-         Contents := Preprocess_File (Filename => Filename,
-                                      Charset  => Charset);
+         Buffer := Create_From_UTF8 (Filename).Read_File;
+
+         --  Return an empty sring when failing to read the file (i.e: when the
+         --  file has been deleted).
+         if Buffer = null then
+            Buffer := new String'("");
+         end if;
+      end if;
+
+      --  If we have preprocessing data, use LAL's API to preoprocess the file.
+      --  Otherwise, just decode the contents of the document/file.
+
+      if Self.Preprocessing_Data /= No_Preprocessor_Data then
+         Libadalang.Preprocessing.Preprocess
+           (Data        => Self.Preprocessing_Data,
+            Filename    => Filename,
+            Input       => Buffer.all,
+            Contents    => Source,
+            Diagnostics => Diagnostics);
+
+         if Source.Buffer = null then
+            --  Log the diagnostics when processing has failed
+            for Diag of Diagnostics loop
+               Me.Trace (Langkit_Support.Diagnostics.To_Pretty_String (Diag));
+            end loop;
+         end if;
       end if;
+
+      --  Decode the preprocessed buffer (or the initial contents when there is
+      --  no preprocessing needed) in utf-8.
+
+      Decode_Buffer
+        (Buffer      => (if Source.Buffer /= null then
+                            Source.Buffer (1 .. Source.Last)
+                         else
+                            Buffer.all),
+         Charset     => "utf-8",
+         Read_BOM    => Read_BOM,
+         Contents    => Contents,
+         Diagnostics => Diagnostics);
+
+      Free (Source);
+      GNAT.Strings.Free (Buffer);
    end Read;
 
 end LSP.Ada_Handlers.File_Readers;

source/ada/lsp-ada_handlers-file_readers.ads

@@ -21,11 +21,16 @@
 
 with Langkit_Support.File_Readers;
 with Langkit_Support.Diagnostics;
+with Libadalang.Preprocessing;
 
 package LSP.Ada_Handlers.File_Readers is
 
    type LSP_Reader_Interface (Handler : access Message_Handler) is new
-     Langkit_Support.File_Readers.File_Reader_Interface with null record;
+     Langkit_Support.File_Readers.File_Reader_Interface with
+   record
+      Preprocessing_Data : Libadalang.Preprocessing.Preprocessor_Data :=
+           Libadalang.Preprocessing.No_Preprocessor_Data;
+   end record;
 
    overriding procedure Read
      (Self        : LSP_Reader_Interface;

source/ada/lsp-ada_handlers.adb

@@ -94,6 +94,7 @@ with Libadalang.Analysis;
 with Libadalang.Common;    use Libadalang.Common;
 with Libadalang.Doc_Utils;
 with Libadalang.Helpers;
+with Libadalang.Preprocessing;
 
 with GNATdoc.Comments.Helpers;
 
@@ -4682,7 +4683,48 @@ package body LSP.Ada_Handlers is
       procedure Create_Context_For_Non_Aggregate (P : Project_Type) is
          C : constant Context_Access := new Context (Self.Trace);
          Reader : LSP.Ada_Handlers.File_Readers.LSP_Reader_Interface (Self);
+
+         Default_Config : Libadalang.Preprocessing.File_Config;
+         File_Configs   : Libadalang.Preprocessing.File_Config_Maps.Map;
+
+         procedure Set_Line_Mode
+           (Config : in out Libadalang.Preprocessing.File_Config);
+         --  Used to force the preprocessing line mode to Blank_Lines, which
+         --  is needed to preserve the number of lines after preprocessing a
+         --  source file, otherwise LSP requests based on SLOCs will fail.
+
+         -------------------
+         -- Set_Line_Mode --
+         -------------------
+
+         procedure Set_Line_Mode
+           (Config : in out Libadalang.Preprocessing.File_Config) is
+         begin
+            if Config.Enabled then
+               Config.Line_Mode := Libadalang.Preprocessing.Blank_Lines;
+            end if;
+         end Set_Line_Mode;
+
       begin
+         --  Extract the preprocessing options from the context's project
+         --  and create the file reader which will preprocess the files
+         --  accordingly.
+
+         Libadalang.Preprocessing.Extract_Preprocessor_Data_From_Project
+           (Tree           => Self.Project_Tree.all,
+            Project        => P,
+            Default_Config => Default_Config,
+            File_Configs   => File_Configs);
+
+         Libadalang.Preprocessing.Iterate
+           (Default_Config => Default_Config,
+            File_Configs   => File_Configs,
+            Process        => Set_Line_Mode'Access);
+
+         Reader.Preprocessing_Data :=
+           Libadalang.Preprocessing.Create_Preprocessor_Data
+             (Default_Config, File_Configs);
+
          C.Initialize (Reader, Self.Follow_Symlinks);
          C.Load_Project (Tree    => Self.Project_Tree,
                          Root    => P,

testsuite/ada_lsp/preprocessor/p.gpr

@@ -1,2 +1,6 @@
 project p is
+
+   package Compiler is
+      for Default_Switches ("Ada") use ("-gnateDdebug=true");
+   end Compiler;
 end p;