1------------------------------------------------------------------------------
2--                                                                          --
3--                         GNAT COMPILER COMPONENTS                         --
4--                                                                          --
5--                               O U T P U T                                --
6--                                                                          --
7--                                 S p e c                                  --
8--                                                                          --
9--          Copyright (C) 1992-2013, Free Software Foundation, Inc.         --
10--                                                                          --
11-- GNAT is free software;  you can  redistribute it  and/or modify it under --
12-- terms of the  GNU General Public License as published  by the Free Soft- --
13-- ware  Foundation;  either version 3,  or (at your option) any later ver- --
14-- sion.  GNAT is distributed in the hope that it will be useful, but WITH- --
15-- OUT ANY WARRANTY;  without even the  implied warranty of MERCHANTABILITY --
16-- or FITNESS FOR A PARTICULAR PURPOSE.                                     --
17--                                                                          --
18-- As a special exception under Section 7 of GPL version 3, you are granted --
19-- additional permissions described in the GCC Runtime Library Exception,   --
20-- version 3.1, as published by the Free Software Foundation.               --
21--                                                                          --
22-- You should have received a copy of the GNU General Public License and    --
23-- a copy of the GCC Runtime Library Exception along with this program;     --
24-- see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see    --
25-- <http://www.gnu.org/licenses/>.                                          --
26--                                                                          --
27-- GNAT was originally developed  by the GNAT team at  New York University. --
28-- Extensive contributions were provided by Ada Core Technologies Inc.      --
29--                                                                          --
30------------------------------------------------------------------------------
31
32--  This package contains low level output routines used by the compiler for
33--  writing error messages and informational output. It is also used by the
34--  debug source file output routines (see Sprint.Print_Debug_Line).
35
36with Hostparm; use Hostparm;
37with Types;    use Types;
38
39pragma Warnings (Off);
40--  This package is used also by gnatcoll
41with System.OS_Lib; use System.OS_Lib;
42pragma Warnings (On);
43
44package Output is
45   pragma Elaborate_Body;
46
47   type Output_Proc is access procedure (S : String);
48   --  This type is used for the Set_Special_Output procedure. If Output_Proc
49   --  is called, then instead of lines being written to standard error or
50   --  standard output, a call is made to the given procedure for each line,
51   --  passing the line with an end of line character (which is a single
52   --  ASCII.LF character, even in systems which normally use CR/LF or some
53   --  other sequence for line end).
54
55   -----------------
56   -- Subprograms --
57   -----------------
58
59   procedure Set_Special_Output (P : Output_Proc);
60   --  Sets subsequent output to call procedure P. If P is null, then the call
61   --  cancels the effect of a previous call, reverting the output to standard
62   --  error or standard output depending on the mode at the time of previous
63   --  call. Any exception generated by by calls to P is simply propagated to
64   --  the caller of the routine causing the write operation.
65
66   procedure Cancel_Special_Output;
67   --  Cancels the effect of a call to Set_Special_Output, if any. The output
68   --  is then directed to standard error or standard output depending on the
69   --  last call to Set_Standard_Error or Set_Standard_Output. It is never an
70   --  error to call Cancel_Special_Output. It has the same effect as calling
71   --  Set_Special_Output (null).
72
73   procedure Ignore_Output (S : String);
74   --  Does nothing. To disable output, pass Ignore_Output'Access to
75   --  Set_Special_Output.
76
77   procedure Set_Standard_Error;
78   --  Sets subsequent output to appear on the standard error file (whatever
79   --  that might mean for the host operating system, if anything) when
80   --  no special output is in effect. When a special output is in effect,
81   --  the output will appear on standard error only after special output
82   --  has been cancelled.
83
84   procedure Set_Standard_Output;
85   --  Sets subsequent output to appear on the standard output file (whatever
86   --  that might mean for the host operating system, if anything) when no
87   --  special output is in effect. When a special output is in effect, the
88   --  output will appear on standard output only after special output has been
89   --  cancelled. Output to standard output is the default mode before any call
90   --  to either of the Set procedures.
91
92   procedure Set_Output (FD : File_Descriptor);
93   --  Sets subsequent output to appear on the given file descriptor when no
94   --  special output is in effect. When a special output is in effect, the
95   --  output will appear on the given file descriptor only after special
96   --  output has been cancelled.
97
98   procedure Indent;
99   --  Increases the current indentation level. Whenever a line is written
100   --  (triggered by Eol), an appropriate amount of whitespace is added to the
101   --  beginning of the line, wrapping around if it gets too long.
102
103   procedure Outdent;
104   --  Decreases the current indentation level
105
106   procedure Write_Char (C : Character);
107   --  Write one character to the standard output file. If the character is LF,
108   --  this is equivalent to Write_Eol.
109
110   procedure Write_Erase_Char (C : Character);
111   --  If last character in buffer matches C, erase it, otherwise no effect
112
113   procedure Write_Eol;
114   --  Write an end of line (whatever is required by the system in use, e.g.
115   --  CR/LF for DOS, or LF for Unix) to the standard output file. This routine
116   --  also empties the line buffer, actually writing it to the file. Note that
117   --  Write_Eol is the only routine that causes any actual output to be
118   --  written. Trailing spaces are removed.
119
120   procedure Write_Eol_Keep_Blanks;
121   --  Similar as Write_Eol, except that trailing spaces are not removed
122
123   procedure Write_Int (Val : Int);
124   --  Write an integer value with no leading blanks or zeroes. Negative values
125   --  are preceded by a minus sign).
126
127   procedure Write_Spaces (N : Nat);
128   --  Write N spaces
129
130   procedure Write_Str (S : String);
131   --  Write a string of characters to the standard output file. Note that
132   --  end of line is normally handled separately using WRITE_EOL, but it is
133   --  allowable for the string to contain LF (but not CR) characters, which
134   --  are properly interpreted as end of line characters. The string may also
135   --  contain horizontal tab characters.
136
137   procedure Write_Line (S : String);
138   --  Equivalent to Write_Str (S) followed by Write_Eol;
139
140   function Last_Char return Character;
141   --  Returns last character written on the current line, or null if the
142   --  current line is (so far) empty.
143
144   procedure Delete_Last_Char;
145   --  Deletes last character written on the current line, no effect if the
146   --  current line is (so far) empty.
147
148   function Column return Pos;
149   pragma Inline (Column);
150   --  Returns the number of the column about to be written (e.g. a value of 1
151   --  means the current line is empty).
152
153   -------------------------
154   -- Buffer Save/Restore --
155   -------------------------
156
157   --  This facility allows the current line buffer to be saved and restored
158
159   type Saved_Output_Buffer is private;
160   --  Type used for Save/Restore_Buffer
161
162   Buffer_Max : constant := Hostparm.Max_Line_Length;
163   --  Maximal size of a buffered output line
164
165   function Save_Output_Buffer return Saved_Output_Buffer;
166   --  Save current line buffer and reset line buffer to empty
167
168   procedure Restore_Output_Buffer (S : Saved_Output_Buffer);
169   --  Restore previously saved output buffer. The value in S is not affected
170   --  so it is legitimate to restore a buffer more than once.
171
172   --------------------------
173   -- Debugging Procedures --
174   --------------------------
175
176   --  The following procedures are intended only for debugging purposes,
177   --  for temporary insertion into the text in environments where a debugger
178   --  is not available. They all have non-standard very short lower case
179   --  names, precisely to make sure that they are only used for debugging.
180
181   procedure w (C : Character);
182   --  Dump quote, character, quote, followed by line return
183
184   procedure w (S : String);
185   --  Dump string followed by line return
186
187   procedure w (V : Int);
188   --  Dump integer followed by line return
189
190   procedure w (B : Boolean);
191   --  Dump Boolean followed by line return
192
193   procedure w (L : String; C : Character);
194   --  Dump contents of string followed by blank, quote, character, quote
195
196   procedure w (L : String; S : String);
197   --  Dump two strings separated by blanks, followed by line return
198
199   procedure w (L : String; V : Int);
200   --  Dump contents of string followed by blank, integer, line return
201
202   procedure w (L : String; B : Boolean);
203   --  Dump contents of string followed by blank, Boolean, line return
204
205private
206   --  Note: the following buffer and column position are maintained by the
207   --  subprograms defined in this package, and cannot be directly modified or
208   --  accessed by a client.
209
210   Buffer : String (1 .. Buffer_Max + 1) := (others => '*');
211   for Buffer'Alignment use 4;
212   --  Buffer used to build output line. We do line buffering because it
213   --  is needed for the support of the debug-generated-code option (-gnatD).
214   --  Historically it was first added because on VMS, line buffering is
215   --  needed with certain file formats. So in any case line buffering must
216   --  be retained for this purpose, even if other reasons disappear. Note
217   --  any attempt to write more output to a line than can fit in the buffer
218   --  will be silently ignored. The alignment clause improves the efficiency
219   --  of the save/restore procedures.
220
221   Next_Col : Positive range 1 .. Buffer'Length + 1 := 1;
222   --  Column about to be written
223
224   type Saved_Output_Buffer is record
225      Buffer          : String (1 .. Buffer_Max + 1);
226      Next_Col        : Positive;
227      Cur_Indentation : Natural;
228   end record;
229
230end Output;
231