fbuf: New data structure for buffered file I/O.

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

diff --git a/src/data/make-file.h b/src/data/make-file.h
index ce56758ee87d2b9abc9d80f57e0958a636d30e5c..d908db336681c9b4179c126abe601f7b1c34f126 100644 (file)
--- a/src/data/make-file.h
+++ b/src/data/make-file.h
@@ -1,5 +1,5 @@
 /* PSPP - a program for statistical analysis.
-   Copyright (C) 2004 Free Software Foundation, Inc.
+   Copyright (C) 2004, 2010 Free Software Foundation, Inc.
 
    This program is free software: you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
@@ -14,19 +14,43 @@
    You should have received a copy of the GNU General Public License
    along with this program.  If not, see <http://www.gnu.org/licenses/>. */
 
-#ifndef MKFILE_H
-#define MKFILE_H
+#ifndef MAKE_FILE_H
+#define MAKE_FILE_H
 
+#include <stdbool.h>
+#include <stdio.h>
+#include <sys/types.h>
 
-/* Creates a temporary file and stores its name in *FILE_NAME and
-   a file descriptor for it in *FD.  Returns success.  Caller is
-   responsible for freeing *FILE_NAME. */
-int make_temp_file (int *fd, char **file_name);
+struct file_handle;
 
+/* Prepares to atomically replace a (potentially) existing file by a new file,
+   by creating a temporary file with the given PERMISSIONS bits.
 
-/* Creates a temporary file and stores its name in *FILE_NAME and
-   a file stream for it in *FP.  Returns success.  Caller is
-   responsible for freeing *FILE_NAME. */
-int make_unique_file_stream (FILE **fp, char **file_name) ;
+   Special files are an exception: they are not atomically
+   replaced but simply opened for writing.
+
+   If successful, returns a ticket that can be used to commit or abort the file
+   replacement.  If neither action is taken, program termination via signal
+   will abort.  Depending on the function, stores a file descriptor in *FD or a
+   stream in *FP for the newly opened file.  The descriptor or stream is opened
+   for writing a binary file if BINARY is true, otherwise a text file (this
+   disctinction only matters on Windows).
+
+   On error, returns NULL and stores NULL in *FP or -1 in *FD.
+
+   The caller is responsible for closing *FP or *FD. */
+
+struct replace_file *replace_file_start (const struct file_handle *fh,
+                                         bool binary, mode_t permissions,
+                                         FILE **fp);
+struct replace_file *replace_file_start_fd (const struct file_handle *fh,
+                                            bool binary,
+                                            mode_t permissions, int *fd);
+
+/* 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 */