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https://github.com/git/git.git
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b1c9b798a6
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 <david.barr@cordelta.com>
Signed-off-by: Jonathan Nieder <jrnieder@gmail.com>
132 lines
2.9 KiB
C
132 lines
2.9 KiB
C
/*
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* Licensed under a two-clause BSD-style license.
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* See LICENSE for details.
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*/
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#include "git-compat-util.h"
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#include "line_buffer.h"
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#include "strbuf.h"
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#define COPY_BUFFER_LEN 4096
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int buffer_init(struct line_buffer *buf, const char *filename)
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{
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buf->infile = filename ? fopen(filename, "r") : stdin;
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if (!buf->infile)
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return -1;
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return 0;
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}
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int buffer_fdinit(struct line_buffer *buf, int fd)
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{
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buf->infile = fdopen(fd, "r");
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if (!buf->infile)
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return -1;
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return 0;
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}
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int buffer_tmpfile_init(struct line_buffer *buf)
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{
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buf->infile = tmpfile();
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if (!buf->infile)
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return -1;
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return 0;
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}
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int buffer_deinit(struct line_buffer *buf)
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{
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int err;
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if (buf->infile == stdin)
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return ferror(buf->infile);
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err = ferror(buf->infile);
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err |= fclose(buf->infile);
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return err;
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}
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FILE *buffer_tmpfile_rewind(struct line_buffer *buf)
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{
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rewind(buf->infile);
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return buf->infile;
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}
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long buffer_tmpfile_prepare_to_read(struct line_buffer *buf)
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{
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long pos = ftell(buf->infile);
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if (pos < 0)
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return error("ftell error: %s", strerror(errno));
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if (fseek(buf->infile, 0, SEEK_SET))
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return error("seek error: %s", strerror(errno));
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return pos;
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}
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int buffer_read_char(struct line_buffer *buf)
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{
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return fgetc(buf->infile);
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}
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/* Read a line without trailing newline. */
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char *buffer_read_line(struct line_buffer *buf)
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{
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char *end;
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if (!fgets(buf->line_buffer, sizeof(buf->line_buffer), buf->infile))
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/* Error or data exhausted. */
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return NULL;
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end = buf->line_buffer + strlen(buf->line_buffer);
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if (end[-1] == '\n')
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end[-1] = '\0';
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else if (feof(buf->infile))
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; /* No newline at end of file. That's fine. */
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else
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/*
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* Line was too long.
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* There is probably a saner way to deal with this,
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* but for now let's return an error.
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*/
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return NULL;
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return buf->line_buffer;
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}
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char *buffer_read_string(struct line_buffer *buf, uint32_t len)
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{
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strbuf_reset(&buf->blob_buffer);
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strbuf_fread(&buf->blob_buffer, len, buf->infile);
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return ferror(buf->infile) ? NULL : buf->blob_buffer.buf;
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}
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void buffer_read_binary(struct line_buffer *buf,
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struct strbuf *sb, uint32_t size)
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{
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strbuf_fread(sb, size, buf->infile);
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}
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void buffer_copy_bytes(struct line_buffer *buf, uint32_t len)
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{
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char byte_buffer[COPY_BUFFER_LEN];
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uint32_t in;
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while (len > 0 && !feof(buf->infile) && !ferror(buf->infile)) {
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in = len < COPY_BUFFER_LEN ? len : COPY_BUFFER_LEN;
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in = fread(byte_buffer, 1, in, buf->infile);
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len -= in;
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fwrite(byte_buffer, 1, in, stdout);
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if (ferror(stdout)) {
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buffer_skip_bytes(buf, len);
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return;
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}
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}
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}
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void buffer_skip_bytes(struct line_buffer *buf, uint32_t len)
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{
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char byte_buffer[COPY_BUFFER_LEN];
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uint32_t in;
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while (len > 0 && !feof(buf->infile) && !ferror(buf->infile)) {
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in = len < COPY_BUFFER_LEN ? len : COPY_BUFFER_LEN;
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in = fread(byte_buffer, 1, in, buf->infile);
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len -= in;
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}
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}
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void buffer_reset(struct line_buffer *buf)
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{
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strbuf_release(&buf->blob_buffer);
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}
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