htrdr

commit 39c7f999f3adc1665695a1aa58f2db9eeaa7c094
parent 708cb160434792ffbf9d8196544fb29d81e6add4
Author: Vincent Forest <vincent.forest@meso-star.com>
Date:   Thu,  9 Aug 2018 11:42:19 +0200

Implement the is_file_updated internal function

This function checks that the submitted filename was modified wrt
previous mtime and size data saved in a "stamp" file located in the
current execution directory. If either the stamp file did not exist or
if its content is different of the data returned by the "stat" system
function, then the file is considered as updated.

Diffstat:
M
src/htrdr.c
 | 
100
+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++--
M
src/htrdr_c.h
 | 
6
++++++

2 files changed, 104 insertions(+), 2 deletions(-)
diff --git a/src/htrdr.c b/src/htrdr.c
@@ -13,9 +13,10 @@
  * You should have received a copy of the GNU General Public License
  * along with this program. If not, see <http://www.gnu.org/licenses/>. */
 
-#define _POSIX_C_SOURCE 200112L /* open support */
+#define _POSIX_C_SOURCE 200809L /* stat.st_tim support */
 
 #include "htrdr.h"
+#include "htrdr_c.h"
 #include "htrdr_args.h"
 #include "htrdr_buffer.h"
 #include "htrdr_camera.h"
@@ -25,6 +26,7 @@
 
 #include <rsys/clock_time.h>
 #include <rsys/mem_allocator.h>
+#include <rsys/str.h>
 
 #include <star/s3d.h>
 #include <star/s3daw.h>
@@ -32,10 +34,12 @@
 #include <star/svx.h>
 
 #include <errno.h>
+#include <fcntl.h> /* open */
+#include <libgen.h> /* basename */
 #include <stdarg.h>
 #include <stdio.h>
 #include <unistd.h>
-#include <fcntl.h> /* open */
+#include <sys/time.h> /* timespec */
 #include <sys/stat.h> /* S_IRUSR & S_IWUSR */
 
 #include <omp.h>
@@ -432,3 +436,95 @@ htrdr_log_warn(struct htrdr* htrdr, const char* msg, ...)
   va_end(vargs_list);
 }
 
+/*******************************************************************************
+ * Local functions
+ ******************************************************************************/
+res_T
+is_file_updated(struct htrdr* htrdr, const char* filename, int* out_upd)
+{
+  struct str str;
+  struct stat statbuf;
+  ssize_t n;
+  off_t size;
+  struct timespec mtime;
+  int fd = -1;
+  int err;
+  int upd;
+  res_T res = RES_OK;
+  ASSERT(htrdr && filename && out_upd);
+
+  str_init(htrdr->allocator, &str);
+
+  err = stat(filename, &statbuf);
+  if(err) {
+    htrdr_log_err(htrdr, "%s: could not stat the file -- %s.\n",
+      filename, strerror(errno));
+    res = RES_IO_ERR;
+    goto error;
+  }
+
+  if(!S_ISREG(statbuf.st_mode)) {
+    htrdr_log_err(htrdr, "%s: not a regular file.\n", filename);
+    res = RES_IO_ERR;
+    goto error;
+  }
+
+  #define CHK_STR(Func, ErrMsg) {                                              \
+    res = str_##Func;                                                          \
+    if(res != RES_OK) {                                                        \
+      htrdr_log_err(htrdr, "%s: "ErrMsg"\n", filename);                        \
+      goto error;                                                              \
+    }                                                                          \
+  } (void)0
+  CHK_STR(set(&str, filename), "could not copy the filename");
+  CHK_STR(set(&str, basename(str_get(&str))), "could not setup the basename");
+  CHK_STR(insert(&str, 0, ".htrdr_"), "could not setup the stamp prefix");
+  CHK_STR(append(&str, ".stamp"), "could not setup the stamp extension");
+  #undef CHK_STR
+
+  #define CHK_IO(Func, ErrMsg) {                                               \
+    if((Func) < 0) {                                                           \
+      htrdr_log_err(htrdr, "%s: "ErrMsg" -- %s.\n",                            \
+        str_cget(&str), strerror(errno));                                      \
+      res = RES_IO_ERR;                                                        \
+      goto error;                                                              \
+    }                                                                          \
+  } (void) 0
+
+  fd = open(str_cget(&str), O_CREAT|O_RDWR, S_IRUSR|S_IWUSR);
+  CHK_IO(fd, "could not open/create the file");
+
+  CHK_IO(n = read(fd, &mtime, sizeof(mtime)), "could read the `mtime' data");
+
+  upd = (size_t)n != sizeof(mtime)
+      ||mtime.tv_nsec != statbuf.st_mtim.tv_nsec
+      ||mtime.tv_sec  != statbuf.st_mtim.tv_sec;
+
+  if(!upd) {
+    CHK_IO(n = read(fd, &size, sizeof(size)), "could not read the `size' data");
+    upd = (size_t)n != sizeof(size) || statbuf.st_size != size;
+  }
+
+  if(upd) {
+    CHK_IO(lseek(fd, 0, SEEK_SET), "could not rewind the file descriptor");
+
+    /* NOTE: Ignore n >=0 but != sizeof(DATA). In such case stamp is currupted
+     * and on the next invocation on the same filename, this function will
+     * return 1 */
+    n = write(fd, &statbuf.st_mtim, sizeof(statbuf.st_mtim));
+    CHK_IO(n, "could not update the `mtime' data");
+    n = write(fd, &statbuf.st_size, sizeof(statbuf.st_size));
+    CHK_IO(n, "could not update the `size' data");
+
+    CHK_IO(fsync(fd), "could not sync the file with storage device");
+  }
+
+  #undef CHK_IO
+exit:
+  *out_upd = upd;
+  str_release(&str);
+  if(fd >= 0) CHK(close(fd) == 0);
+  return res;
+error:
+  goto exit;
+}
diff --git a/src/htrdr_c.h b/src/htrdr_c.h
@@ -33,5 +33,11 @@ wavelength_to_wavenumber(const double lambda/*In nanometer*/)
   return wavenumber_to_wavelength(lambda);
 }
 
+extern LOCAL_SYM res_T
+is_file_updated
+  (struct htrdr* htrdr,
+   const char* filename,
+   int* is_upd);
+
 #endif /* HTRDR_C_H */