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------------------------------------------------------------------------------
-- --
-- GNAT COMPILER COMPONENTS --
-- --
-- P R J . E X T --
-- --
-- S p e c --
-- --
-- Copyright (C) 2000-2013, Free Software Foundation, Inc. --
-- --
-- GNAT is free software; you can redistribute it and/or modify it under --
-- terms of the GNU General Public License as published by the Free Soft- --
-- ware Foundation; either version 3, or (at your option) any later ver- --
-- sion. GNAT is distributed in the hope that it will be useful, but WITH- --
-- OUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY --
-- or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License --
-- for more details. You should have received a copy of the GNU General --
-- Public License distributed with GNAT; see file COPYING3. If not, go to --
-- http://www.gnu.org/licenses for a complete copy of the license. --
-- --
-- GNAT was originally developed by the GNAT team at New York University. --
-- Extensive contributions were provided by Ada Core Technologies Inc. --
-- --
------------------------------------------------------------------------------
-- Subprograms to set, get and cache external references, to be used as
-- External functions in project files.
with GNAT.Dynamic_HTables;
package Prj.Ext is
-------------------------
-- External References --
-------------------------
-- External references influence the way a project tree is processed (in
-- particular they provide the values for the typed string variables that
-- are then used in case constructions).
-- External references are project-tree specific, so that when multiple
-- trees are loaded in parallel we can have different scenarios (or even
-- load the same tree twice and see different views of it).
type External_References is private;
No_External_Refs : constant External_References;
procedure Initialize
(Self : out External_References;
Copy_From : External_References := No_External_Refs);
-- Initialize Self, and copy all values from Copy_From if needed.
-- This has no effect if Self was already initialized.
procedure Free (Self : in out External_References);
-- Free memory used by Self
type External_Source is
(From_Command_Line,
From_Environment,
From_External_Attribute);
-- Indicates where was the value of an external reference defined. They are
-- prioritized in that order, so that a user can always use the command
-- line to override a value coming from his environment, or an environment
-- variable to override a value defined in an aggregate project through the
-- "for External()..." attribute.
procedure Add
(Self : External_References;
External_Name : String;
Value : String;
Source : External_Source := External_Source'First;
Silent : Boolean := False);
-- Add an external reference (or modify an existing one). No overriding is
-- done if the Source's priority is less than the one used to previously
-- set the value of the variable. The default for Source is such that
-- overriding always occurs. When Silent is True, nothing is output even
-- with non default verbosity.
function Value_Of
(Self : External_References;
External_Name : Name_Id;
With_Default : Name_Id := No_Name)
return Name_Id;
-- Get the value of an external reference, and cache it for future uses
function Check
(Self : External_References;
Declaration : String) return Boolean;
-- Check that an external declaration <external>=<value> is correct.
-- If it is correct, the external reference is Added.
procedure Reset (Self : External_References);
-- Clear the internal data structure that stores the external references
-- and free any allocated memory.
private
-- Use a Static_HTable, rather than a Simple_HTable
-- The issue is that we need to be able to copy the contents of the table
-- (in Initialize), but this isn't doable for Simple_HTable for which
-- iterators do not return the key.
type Name_To_Name;
type Name_To_Name_Ptr is access all Name_To_Name;
type Name_To_Name is record
Key : Name_Id;
Value : Name_Id;
Source : External_Source;
Next : Name_To_Name_Ptr;
end record;
procedure Set_Next (E : Name_To_Name_Ptr; Next : Name_To_Name_Ptr);
function Next (E : Name_To_Name_Ptr) return Name_To_Name_Ptr;
function Get_Key (E : Name_To_Name_Ptr) return Name_Id;
package Name_To_Name_HTable is new GNAT.Dynamic_HTables.Static_HTable
(Header_Num => Header_Num,
Element => Name_To_Name,
Elmt_Ptr => Name_To_Name_Ptr,
Null_Ptr => null,
Set_Next => Set_Next,
Next => Next,
Key => Name_Id,
Get_Key => Get_Key,
Hash => Hash,
Equal => "=");
-- General type for htables associating name_id to name_id. This is in
-- particular used to store the values of external references.
type Instance_Access is access all Name_To_Name_HTable.Instance;
type External_References is record
Refs : Instance_Access;
-- External references are stored in this hash table (and manipulated
-- through subprogrames in prj-ext.ads). External references are
-- project-tree specific so that one can load the same tree twice but
-- have two views of it, for instance.
end record;
No_External_Refs : constant External_References := (Refs => null);
end Prj.Ext;