FIXED: Handle source files with epoch time stamp

Flatpak seems to set the modification time of all times in the sandbox
to the epoch (0).  This was used as a special value to indicate the
source file was not a file.   We now keep a seperate flag and use the
_integer_ 0 to indicate something is not a source file in the Prolog
world.   It is probably better to use something else, but this avoids
type issues in possibly unknown dependent code.

boot/init.pl

@@ -2290,7 +2290,7 @@
     fail.
 '$noload'(_, FullFile, _Options) :-
     '$time_source_file'(FullFile, Time, system),
-    Time > 0.0,
+    float(Time),
     !.
 '$noload'(not_loaded, FullFile, _) :-
     source_file(FullFile),
@@ -3000,7 +3000,7 @@
 	  error(_, _),
 	  fail),
     !.
-'$modified_id'(_, 0.0, _).
+'$modified_id'(_, 0, _).
 
 
 '$compile_type'(What) :-

boot/syspred.pl

@@ -245,8 +245,8 @@
 %   if the canonical name  as   defined  by  absolute_file_name/2 is
 %   known as a loaded filename.
 %
-%   Note that Time = 0.0 is used by  PlDoc and other code that needs
-%   to create a file record without being interested in the time.
+%   Note that Time = 0 is used by PlDoc and other code that needs to
+%   create a file record without being interested in the time.
 
 source_file(File) :-
     (   current_prolog_flag(access_level, user)
@@ -260,7 +260,7 @@
         ), !
     ;   '$time_source_file'(File, Time, Level)
     ),
-    Time > 0.0.
+    float(Time).
 
 %!  source_file(+Head, -File) is semidet.
 %!  source_file(?Head, ?File) is nondet.

src/pl-incl.h

@@ -1989,6 +1989,7 @@ struct sourceFile
   unsigned int	number_of_clauses;	/* number of clauses */
   unsigned int	index;			/* index number (1,2,...) */
   unsigned int	references;		/* Reference count */
+  unsigned	isfile     : 1;		/* Is a real file */
   unsigned	system     : 1;		/* system sourcefile: do not reload */
   unsigned	from_state : 1;		/* Loaded from resource DB state */
   unsigned	resource   : 1;		/* Loaded from resource DB file */

src/pl-qlf.c

@@ -164,16 +164,16 @@ Below is an informal description of the format of a `.qlf' file:
 			XR_FUNCTOR <XR/name> <num>	% functor
 			XR_PRED    <XR/fdef> <XR/module>% predicate
 			XR_MODULE  <XR/name>		% module
-			XR_FILE	   's'|'u' <XR/atom> <time>
+			XR_FILE	   's'|'u'|'S'|'U' <XR/atom> <time>
 				   '-'
 			XR_BLOB_TYPE <len><chars>	% blob type-name
 <term>		::=	<num>				% # variables in term
 			<theterm>
 <theterm>	::=	<XR/atomic>			% atomic data
 		      | 'v' <num>			% variable
 		      | 't' <XR/functor> {<theterm>}	% compound
-<system>	::=	's'				% system source file
-		      | 'u'				% user source file
+<system>	::=	's' | 'S'			% system source file
+		      | 'u' | 'U'			% user source file
 <time>		::=	<word>				% time file was loaded
 <line>		::=	<num>
 <codes>		::=	<num> {<code>}
@@ -841,6 +841,8 @@ loadXRc(DECL_LD wic_state *state, int c)
       switch( (c=Qgetc(fd)) )
       { case 'u':
 	case 's':
+	case 'U':
+	case 'S':
 	{ atom_t name   = word2atom(loadXR(state));
 	  double time   = qlfGetDouble(fd);
 	  PL_chars_t text;
@@ -853,8 +855,9 @@ loadXRc(DECL_LD wic_state *state, int c)
 	  PL_STRINGS_RELEASE();
 
 	  if ( sf->mtime == 0.0 )
-	  { sf->mtime   = time;
-	    sf->system = (c == 's' ? TRUE : FALSE);
+	  { sf->mtime  = time;
+	    sf->system = !!(c == 's' || c == 'S');
+	    sf->isfile = !!(c == 's' || c == 'u');
 	  }
 	  sf->count++;
 	  xr = ptr2word(sf);
@@ -1814,7 +1817,7 @@ qlfLoadSource(wic_state *state)
 { IOSTREAM *fd = state->wicFd;
   char *str = qlfGetString(fd, NULL);
   double time = qlfGetDouble(fd);
-  unsigned int issys = (Qgetc(fd) == 's') ? TRUE : FALSE;
+  int ftype = Qgetc(fd);
   atom_t fname;
 
   if ( !str )
@@ -1830,7 +1833,8 @@ qlfLoadSource(wic_state *state)
   state->currentSource = lookupSourceFile(fname, TRUE);
   PL_unregister_atom(fname);		/* locked with sourceFile */
   state->currentSource->mtime = time;
-  state->currentSource->system = issys&0x1;
+  state->currentSource->system = !!(ftype == 's' || ftype == 'S');
+  state->currentSource->isfile = !!(ftype == 's' || ftype == 'u');
   if ( GD->bootsession )		/* (**) */
     state->currentSource->count++;
   else
@@ -2485,6 +2489,13 @@ saveXRProc(DECL_LD wic_state *state, Procedure p)
   saveXRModule(state, p->definition->module);
 }
 
+static inline int
+src_file_status(const SourceFile f)
+{ if ( f->isfile )
+    return f->system ? 's' : 'u';
+  else
+    return f->system ? 'S' : 'U';
+}
 
 #define saveXRSourceFile(state, f) LDFUNC(saveXRSourceFile, state, f)
 static void
@@ -2499,7 +2510,7 @@ saveXRSourceFile(DECL_LD wic_state *state, SourceFile f)
   if ( f )
   { DEBUG(MSG_QLF_XR, Sdprintf("XR(%d) = file %s\n",
 			       state->savedXRTableId, stringAtom(f->name)));
-    Sputc(f->system ? 's' : 'u', fd);
+    Sputc(src_file_status(f), fd);
     saveXR(state, f->name);
     qlfPutDouble(f->mtime, fd);
   } else
@@ -3666,7 +3677,7 @@ qlfSaveSource(wic_state *state, SourceFile f)
   Sputc('F', fd);
   qlfPutString(text.text.t, text.length, fd);
   qlfPutDouble(f->mtime, fd);
-  Sputc(f->system ? 's' : 'u', fd);
+  Sputc(src_file_status(f), fd);
   PL_STRINGS_RELEASE();
 
   state->currentSource = f;

src/pl-srcfile.c

@@ -3,7 +3,7 @@
     Author:        Jan Wielemaker
     E-mail:        J.Wielemaker@vu.nl
     WWW:           http://www.swi-prolog.org
-    Copyright (c)  2014-2021, VU University Amsterdam
+    Copyright (c)  2014-2024, VU University Amsterdam
 			      CWI, Amsterdam
 			      SWI-Prolog Solutions b.v.
     All rights reserved.
@@ -303,6 +303,7 @@ lookupSourceFile_unlocked(atom_t name, int create)
   { file = allocHeapOrHalt(sizeof(*file));
     memset(file, 0, sizeof(*file));
 
+    file->mtime	     = 0.0;
     file->name       = name;
     file->system     = GD->bootsession&1;
     file->from_state = GD->bootsession&1;
@@ -639,6 +640,16 @@ PRED_IMPL("$source_file_predicates", 2, source_file_predicates, 0)
 }
 
 
+#define unify_src_file_time(t, f) LDFUNC(unify_src_file_time, t, f)
+
+static int
+unify_src_file_time(DECL_LD term_t t, const SourceFile f)
+{ if ( f->isfile )
+    return PL_unify_float(t, f->mtime);
+
+  return PL_unify_integer(t, 0);
+}
+
 static
 PRED_IMPL("$time_source_file", 3, time_source_file, PL_FA_NONDETERMINISTIC)
 { PRED_LD
@@ -669,7 +680,7 @@ PRED_IMPL("$time_source_file", 3, time_source_file, PL_FA_NONDETERMINISTIC)
       continue;
 
     if ( PL_unify_atom(file, f->name) &&
-	 PL_unify_float(time, f->mtime) &&
+	 unify_src_file_time(time, f) &&
 	 PL_unify_atom(type, f->system ? ATOM_system : ATOM_user) )
     { PL_close_foreign_frame(fid);
       ForeignRedoInt(index+1);
@@ -1694,16 +1705,25 @@ static
 PRED_IMPL("$start_consult", 2, start_consult, 0)
 { PRED_LD
   atom_t name;
-  double time;
-
   term_t file = A1;
   term_t modified = A2;
 
-  if ( PL_get_atom_ex(file, &name) &&
-       PL_get_float_ex(modified, &time) )
-  { SourceFile sf = lookupSourceFile(name, TRUE);
+  if ( PL_get_atom_ex(file, &name) )
+  { int isfile, i;
+    double mtime;
+
+    if ( PL_get_integer(modified, &i) && i == 0 )
+    { isfile = FALSE;
+      mtime = 0.0;
+    } else if ( PL_get_float_ex(modified, &mtime) )
+    { isfile = TRUE;
+    } else
+      return FALSE;
+
+    SourceFile sf = lookupSourceFile(name, TRUE);
 
-    sf->mtime = time;
+    sf->mtime = mtime;
+    sf->isfile = isfile&1;
     startConsult(sf);
     releaseSourceFile(sf);