Allow output files to overwrite input files (bug #21280). Thanks to

[pspp-builds.git] / src / data / make-file.h

diff --git a/src/data/make-file.h b/src/data/make-file.h
index ce56758ee87d2b9abc9d80f57e0958a636d30e5c..19d33ebe76bfc070b0f28aed4c11bc61c89b7111 100644 (file)
--- a/src/data/make-file.h
+++ b/src/data/make-file.h
@@ -29,4 +29,31 @@ int make_temp_file (int *fd, char **file_name);
    responsible for freeing *FILE_NAME. */
 int make_unique_file_stream (FILE **fp, char **file_name) ;
 
+
+/* Prepares to atomically replace a (potentially) existing file
+   by a new file, by creating a temporary file with the given
+   PERMISSIONS bits in the same directory as *FILE_NAME.
+
+   Special files are an exception: they are not atomically
+   replaced but simply opened for writing.
+
+   If successful, stores the temporary file's name in *TMP_NAME
+   and a stream for it opened according to MODE (which should be
+   "w" or "wb") in *FP.  Returns a ticket that can be used to
+   commit or abort the file replacement.  If neither action has
+   yet been taken, program termination via signal will cause
+   *TMP_FILE to be unlinked.
+
+   The caller is responsible for closing *FP, but *TMP_NAME is
+   owned by the callee. */
+struct replace_file *replace_file_start (const char *file_name,
+                                         const char *mode, mode_t permissions,
+                                         FILE **fp, char **tmp_name);
+
+/* Commits or aborts the replacement of a (potentially) existing
+   file by a new file, using the ticket returned by
+   replace_file_start.  Returns success. */
+bool replace_file_commit (struct replace_file *);
+bool replace_file_abort (struct replace_file *);
+
 #endif /* make-file.h */