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1 ------------------------------------------------------------------------------
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2 -- --
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3 -- GNAT COMPILER COMPONENTS --
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4 -- --
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5 -- G N A T . L O C K _ F I L E S --
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6 -- --
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7 -- S p e c --
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8 -- --
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9 -- Copyright (C) 1995-2017, AdaCore --
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10 -- --
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11 -- GNAT is free software; you can redistribute it and/or modify it under --
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12 -- terms of the GNU General Public License as published by the Free Soft- --
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13 -- ware Foundation; either version 3, or (at your option) any later ver- --
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14 -- sion. GNAT is distributed in the hope that it will be useful, but WITH- --
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15 -- OUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY --
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16 -- or FITNESS FOR A PARTICULAR PURPOSE. --
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17 -- --
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18 -- As a special exception under Section 7 of GPL version 3, you are granted --
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19 -- additional permissions described in the GCC Runtime Library Exception, --
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20 -- version 3.1, as published by the Free Software Foundation. --
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21 -- --
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22 -- You should have received a copy of the GNU General Public License and --
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23 -- a copy of the GCC Runtime Library Exception along with this program; --
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24 -- see the files COPYING3 and COPYING.RUNTIME respectively. If not, see --
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25 -- <http://www.gnu.org/licenses/>. --
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26 -- --
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27 -- GNAT was originally developed by the GNAT team at New York University. --
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28 -- Extensive contributions were provided by Ada Core Technologies Inc. --
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29 -- --
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30 ------------------------------------------------------------------------------
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31
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32 -- This package contains the necessary routines for using files for the
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33 -- purpose of providing reliable system wide locking capability.
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34
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35 package GNAT.Lock_Files is
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36 pragma Preelaborate;
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37
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38 Lock_Error : exception;
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39 -- Exception raised if file cannot be locked
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40
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41 subtype Path_Name is String;
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42 -- Pathname is used by all services provided in this unit to specify
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43 -- directory name and file name. On DOS based systems both directory
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44 -- separators are handled (i.e. slash and backslash).
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45
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46 procedure Lock_File
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47 (Directory : Path_Name;
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48 Lock_File_Name : Path_Name;
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49 Wait : Duration := 1.0;
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50 Retries : Natural := Natural'Last);
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51 -- Create a lock file Lock_File_Name in directory Directory. If the file
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52 -- cannot be locked because someone already owns the lock, this procedure
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53 -- waits Wait seconds and retries at most Retries times. If the file
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54 -- still cannot be locked, Lock_Error is raised. The default is to try
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55 -- every second, almost forever (Natural'Last times). The full path of
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56 -- the file is constructed by concatenating Directory and Lock_File_Name.
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57 -- Directory can optionally terminate with a directory separator.
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58
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59 procedure Lock_File
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60 (Lock_File_Name : Path_Name;
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61 Wait : Duration := 1.0;
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62 Retries : Natural := Natural'Last);
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63 -- See above. The full lock file path is given as one string
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64
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65 procedure Unlock_File (Directory : Path_Name; Lock_File_Name : Path_Name);
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66 -- Unlock a file. Directory can optionally terminate with a directory
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67 -- separator.
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68
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69 procedure Unlock_File (Lock_File_Name : Path_Name);
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70 -- Unlock a file whose full path is given in Lock_File_Name
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71
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72 end GNAT.Lock_Files;
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