Provide an aliased function IO_TruncateOutputFiles() for other I/O thorns

to check whether or not to truncate existing output files.
The default is to not truncate after recovering. This can be overwritten by
the new boolean parameter IO::truncate_files_after_recovering.


git-svn-id: http://svn.cactuscode.org/arrangements/CactusBase/IOUtil/trunk@219 b32723a9-ab3a-4a60-88e2-2e5d99d7c17a

4 files changed, 87 insertions, 0 deletions

diff --git a/doc/documentation.tex b/doc/documentation.tex
index 3ce359f..bbf1dad 100644
--- a/doc/documentation.tex
+++ b/doc/documentation.tex
@@ -423,6 +423,8 @@ parameters. The most important ones are:
     method used to recover from the recovery file.
   \item {\tt IO::recover\_dir}\\
     directory where the recovery file is located
+  \item {\tt IO::truncate\_files\_after\_recovering}\\
+    whether or not to truncate already existing output files after recovering
 \end{itemize}
 
 To checkpoint your simulation, you need to enable checkpointing by setting
@@ -463,6 +465,15 @@ file(s) to create a single file with unchunked data.
 Note that Cactus checkpoint files are platform independent so you can restart
 from your checkpoint file on a different machine/architecture.
 
+By default, existing output files will be appended to rather than truncated after
+successful recovery. If you don't want this, you can force I/O methods to
+always truncate existing output files. Thorn {\bf IOUtil} provides an aliased
+function for other I/O thorns to call:
+\begin{verbatim}
+  CCTK_INT FUNCTION IO_TruncateOutputFiles (CCTK_POINTER_TO_CONST IN cctkGH)
+\end{verbatim}
+This function simply returns 1 or 0 if output files should or should not be truncated.
+
 \vskip .5cm
 \noindent{\bf WARNING:}
 
diff --git a/interface.ccl b/interface.ccl
index 40f0d99..8ffef18 100644
--- a/interface.ccl
+++ b/interface.ccl
@@ -11,3 +11,11 @@ CCTK_INT FUNCTION Coord_GetDefaultSystem  \
    CCTK_INT IN systemdim)
 
 REQUIRES FUNCTION Coord_GetDefaultSystem
+
+
+CCTK_INT FUNCTION IO_TruncateOutputFiles \
+  (CCTK_POINTER_TO_CONST IN GH)
+
+PROVIDES FUNCTION IO_TruncateOutputFiles \
+  WITH IOUtil_TruncateOutputFiles        \
+  LANGUAGE C
diff --git a/param.ccl b/param.ccl
index e6d0045..50277b8 100644
--- a/param.ccl
+++ b/param.ccl
@@ -296,3 +296,10 @@ INT out_xyplane_zi "z-index (from 0) for 2D planes in xy, overrrides IO::out_xyp
    0:* :: "An index between [0, nz)"
   -1:  :: "Default to physical coordinate IO::out_xyplane_z"
 } -1
+
+
+private:
+
+BOOLEAN truncate_files_after_recovering "Truncate existing output files after recovering ?" STEERABLE = RECOVER
+{
+} "no"
diff --git a/src/Startup.c b/src/Startup.c
index 44f82ef..4dc619c 100644
--- a/src/Startup.c
+++ b/src/Startup.c
@@ -80,6 +80,21 @@ static int DumpParameters (FILE *outfile);
                CCTK_ParameterFilename
                IOUtil_AdvertiseFile
 @@*/
+typedef void (*signal_handler_t) (int sig);
+static signal_handler_t old_signal_handler[32];
+
+static void new_signal_handler (int sig)
+{
+  fprintf (stderr, "called new_signal_handler with signal %d calling %p\n", sig, old_signal_handler[sig]);
+  if (old_signal_handler[sig])
+  {
+    old_signal_handler[sig] (sig);
+  }
+  exit (0);
+}
+
+#include <signal.h>
+
 void IOUtil_Startup (void)
 {
   char parfile[256];
@@ -87,6 +102,15 @@ void IOUtil_Startup (void)
   DECLARE_CCTK_PARAMETERS
 
 
+#if 0
+{
+int i;
+for (i = 0; i < 32; i++)
+{
+  old_signal_handler[i] = signal (i, new_signal_handler);
+}
+}
+#endif
   CCTK_RegisterGHExtensionSetupGH (CCTK_RegisterGHExtension ("IO"), SetupGH);
 
   /* advertise the parameter file */
@@ -139,6 +163,43 @@ int IOUtil_UpdateParFile (const cGH *GH)
 }
 
 
+ /*@@
+   @routine    IOUtil_TruncateOutputFiles
+   @date       Wed 17 November 2004
+   @author     Thomas Radke
+   @desc
+               Aliased function 'IO_TruncateOutputFiles' which can be called
+               by I/O methods to check whether to truncate existing output
+               files or not.
+   @enddesc
+
+   @var        GH
+   @vdesc      pointer to grid hierarchy
+   @vtype      const cGH *
+   @vio        in
+   @endvar
+
+   @returntype CCTK_INT
+   @returndesc 1 or 0 for truncate or not
+               -1 in case of an error (wrong value for GH parameter)
+   @endreturndesc
+@@*/
+CCTK_INT IOUtil_TruncateOutputFiles (const CCTK_POINTER_TO_CONST GH)
+{
+  const ioGH *myGH;
+  DECLARE_CCTK_PARAMETERS
+
+
+  myGH = CCTK_GHExtension (GH, "IO");
+  if (! myGH)
+  {
+    return (-1);
+  }
+
+  return (! myGH->recovered || truncate_files_after_recovering);
+}
+
+
 /********************************************************************
  ***********************    Local Functions   ***********************
  ********************************************************************/