------------------------------------------------------------------------------ -- -- -- 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 = 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;