Add snogpaths.cc and snogpaths.h

These just define some functions to return the install paths
determined at build-time.

.gitignore

@@ -19,6 +19,7 @@ teapot.msh
 # Ignore generated sources
 #
 version.cc
+snogpaths-data.h
 snograw_lua_wrap.cc
 swigluarun.h
 

Makefile.am

@@ -75,7 +75,7 @@ dist-hook:
 
 # Some extra stuff that needs cleaning up
 #
-CLEANFILES = liblua.a snograw.so version.cc
+CLEANFILES = liblua.a snograw.so version.cc snogpaths-data.h
 
 # We only clean up "snograw_lua_wrap.cc" and "swigluarun.h" if it's
 # possible to regenerate them.
@@ -396,9 +396,28 @@ libsnogutil_a_SOURCES = compiler.h cond-var.h excepts.h file-funs.cc	\
 	nice-io.cc nice-io.h num-cores.cc num-cores.h pool.h		\
 	radical-inverse.h random.h random-boost.h random-std.h		\
 	random-rand.h random-tr1.h ref.h rusage.h snogassert.cc		\
-	snogassert.h snogmath.h string-funs.cc string-funs.h thread.h	\
-	threading.h threading-boost.h threading-std.h timeval.cc	\
-	timeval.h val-table.cc unique-ptr.h val-table.h
+	snogassert.h snogmath.h snogpaths.cc snogpaths.h		\
+	string-funs.cc string-funs.h thread.h threading.h		\
+	threading-boost.h threading-std.h timeval.cc timeval.h		\
+	val-table.cc unique-ptr.h val-table.h
+
+
+snogpaths.cc: snogpaths-data.h
+
+# automagically-computed paths
+#
+snogpaths-data.h: Makefile
+	$(snogpaths_verbose)( \
+	  echo '// this file is automatically generated'; \
+	  echo '#define SNOGRAY_PREFIX "$(prefix)"'; \
+	  echo '#define SNOGRAY_BINDIR "$(bindir)"'; \
+	  echo '#define SNOGRAY_PKGDATADIR "$(pkgdatadir)"' ) > "$@"
+
+# automake "silent-rules" hook for snogpaths-data.h
+#
+snogpaths_verbose = $(snogpaths_verbose_$(V))
+snogpaths_verbose_ = $(snogpaths_verbose_$(AM_DEFAULT_VERBOSITY))
+snogpaths_verbose_0 = @echo "  PATHS " $@;
 
 
 ################################################################

snogpaths.cc

@@ -0,0 +1,63 @@
+// snogpaths.cc -- Handling of installation paths
+//
+//  Copyright (C) 2012  Miles Bader <miles@gnu.org>
+//
+// This source code is free software; you can redistribute it and/or
+// modify it under the terms of the GNU General Public License as
+// published by the Free Software Foundation; either version 3, or (at
+// your option) any later version.  See the file COPYING for more details.
+//
+// Written by Miles Bader <miles@gnu.org>
+//
+
+#include "snogpaths-data.h"
+
+#include "snogpaths.h"
+
+
+//
+// Currently these functions just return the statically configured
+// install paths.
+//
+// A better method would be try and make everything "relocatable", by
+// detecting the run-time install prefix, and making other names
+// relative to that.  This can be done as follows:
+//
+// 1. Determine the absolute runtime name of the executable.
+//    There should be a function that main calls to pass in
+//    argv[0]; it can be used as-is if absolute, or searched for
+//    in PATH if not.
+// 
+// 2. Determine the relative bindir suffix by removing the static
+//    install prefix from the static bindir (if the static bindir
+//    is not relative to the static prefix, give up).
+//
+// 3. Remove the filename and relative bindir suffix from the end
+//    of the absolute runtime executable name (if they don't
+//    match, give up), yielding the runtime prefix.
+//
+// 4. Determine the relative suffixes for other paths (datadir,
+//    etc) by removing the static prefix from their static
+//    versions, as in (2).
+//
+// 5. Append the runtime prefix and the relative suffixes
+//    determined in (4) to yield the absolute runtime paths.
+//
+
+std::string
+snogray::installed_prefix ()
+{
+  return SNOGRAY_PREFIX;
+}
+
+std::string
+snogray::installed_bindir ()
+{
+  return SNOGRAY_BINDIR;
+}
+
+std::string
+snogray::installed_pkgdatadir ()
+{
+  return SNOGRAY_PKGDATADIR;
+}

snogpaths.h

@@ -0,0 +1,27 @@
+// snogpaths.h -- Handling of installation paths
+//
+//  Copyright (C) 2012  Miles Bader <miles@gnu.org>
+//
+// This source code is free software; you can redistribute it and/or
+// modify it under the terms of the GNU General Public License as
+// published by the Free Software Foundation; either version 3, or (at
+// your option) any later version.  See the file COPYING for more details.
+//
+// Written by Miles Bader <miles@gnu.org>
+//
+
+#ifndef SNOGRAY_SNOGPATHS_H
+#define SNOGRAY_SNOGPATHS_H
+
+#include <string>
+
+
+namespace snogray {
+
+std::string installed_prefix ();
+std::string installed_bindir ();
+std::string installed_pkgdatadir ();
+
+}
+
+#endif // SNOGRAY_SNOGPATHS_H