From b1c9b798a6dd391aeaea31663a65164815701244 Mon Sep 17 00:00:00 2001 From: Jonathan Nieder Date: Sun, 2 Jan 2011 21:10:59 -0600 Subject: vcs-svn: teach line_buffer about temporary files It can sometimes be useful to write information temporarily to file, to read back later. These functions allow a program to use the line_buffer facilities when doing so. It works like this: 1. find a unique filename with buffer_tmpfile_init. 2. rewind with buffer_tmpfile_rewind. This returns a stdio handle for writing. 3. when finished writing, declare so with buffer_tmpfile_prepare_to_read. The return value indicates how many bytes were written. 4. read whatever portion of the file is needed. 5. if finished, remove the temporary file with buffer_deinit. otherwise, go back to step 2, The svn support would use this to buffer the postimage from delta application until the length is known and fast-import can receive the resulting blob. Based-on-patch-by: David Barr Signed-off-by: Jonathan Nieder --- vcs-svn/line_buffer.c | 24 ++++++++++++++++++++++++ 1 file changed, 24 insertions(+) (limited to 'vcs-svn/line_buffer.c') diff --git a/vcs-svn/line_buffer.c b/vcs-svn/line_buffer.c index e29a81a536..aedf105b70 100644 --- a/vcs-svn/line_buffer.c +++ b/vcs-svn/line_buffer.c @@ -25,6 +25,14 @@ int buffer_fdinit(struct line_buffer *buf, int fd) return 0; } +int buffer_tmpfile_init(struct line_buffer *buf) +{ + buf->infile = tmpfile(); + if (!buf->infile) + return -1; + return 0; +} + int buffer_deinit(struct line_buffer *buf) { int err; @@ -35,6 +43,22 @@ int buffer_deinit(struct line_buffer *buf) return err; } +FILE *buffer_tmpfile_rewind(struct line_buffer *buf) +{ + rewind(buf->infile); + return buf->infile; +} + +long buffer_tmpfile_prepare_to_read(struct line_buffer *buf) +{ + long pos = ftell(buf->infile); + if (pos < 0) + return error("ftell error: %s", strerror(errno)); + if (fseek(buf->infile, 0, SEEK_SET)) + return error("seek error: %s", strerror(errno)); + return pos; +} + int buffer_read_char(struct line_buffer *buf) { return fgetc(buf->infile); -- cgit v1.2.1