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git/vcs-svn/line_buffer.h

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Add stream helper library This library provides thread-unsafe fgets()- and fread()-like functions where the caller does not have to supply a buffer. It maintains a couple of static buffers and provides an API to use them. [rr: allow input from files other than stdin] [jn: with tests, documentation, and error handling improvements] Signed-off-by: David Barr <david.barr@cordelta.com> Signed-off-by: Ramkumar Ramachandra <artagnon@gmail.com> Signed-off-by: Jonathan Nieder <jrnieder@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2010-08-10 00:39:43 +02:00
#ifndef LINE_BUFFER_H_
#define LINE_BUFFER_H_
vcs-svn: collect line_buffer data in a struct Prepare for the line_buffer lib to support input from multiple files, by collecting global state in a struct that can be easily passed around. No API change yet. Signed-off-by: Jonathan Nieder <jrnieder@gmail.com>
2010-10-11 04:39:21 +02:00
#include "strbuf.h"
#define LINE_BUFFER_LEN 10000
struct line_buffer {
char line_buffer[LINE_BUFFER_LEN];
FILE *infile;
};
vcs-svn: remove buffer_read_string All previous users of buffer_read_string have already been converted to use the more intuitive buffer_read_binary, so remove the old API to avoid some confusion. Signed-off-by: Jonathan Nieder <jrnieder@gmail.com>
2011-03-25 05:09:19 +01:00
#define LINE_BUFFER_INIT { "", NULL }
vcs-svn: collect line_buffer data in a struct Prepare for the line_buffer lib to support input from multiple files, by collecting global state in a struct that can be easily passed around. No API change yet. Signed-off-by: Jonathan Nieder <jrnieder@gmail.com>
2010-10-11 04:39:21 +02:00
vcs-svn: teach line_buffer to handle multiple input files Collect the line_buffer state in a newly public line_buffer struct. Callers can use multiple line_buffers to manage input from multiple files at a time. svn-fe's delta applier will use this to stream a delta from svnrdump and the preimage it applies to from fast-import at the same time. The tests don't take advantage of the new features, but I think that's okay. It is easier to find lingering examples of nonreentrant code by searching for "static" in line_buffer.c. Signed-off-by: Jonathan Nieder <jrnieder@gmail.com>
2010-10-11 04:41:06 +02:00
int buffer_init(struct line_buffer *buf, const char *filename);
vcs-svn: allow input from file descriptor Based-on-patch-by: David Barr <david.barr@cordelta.com> Signed-off-by: Jonathan Nieder <jrnieder@gmail.com>
2011-01-03 04:09:38 +01:00
int buffer_fdinit(struct line_buffer *buf, int fd);
vcs-svn: teach line_buffer to handle multiple input files Collect the line_buffer state in a newly public line_buffer struct. Callers can use multiple line_buffers to manage input from multiple files at a time. svn-fe's delta applier will use this to stream a delta from svnrdump and the preimage it applies to from fast-import at the same time. The tests don't take advantage of the new features, but I think that's okay. It is easier to find lingering examples of nonreentrant code by searching for "static" in line_buffer.c. Signed-off-by: Jonathan Nieder <jrnieder@gmail.com>
2010-10-11 04:41:06 +02:00
int buffer_deinit(struct line_buffer *buf);
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 <david.barr@cordelta.com> Signed-off-by: Jonathan Nieder <jrnieder@gmail.com>
2011-01-03 04:10:59 +01:00
int buffer_tmpfile_init(struct line_buffer *buf);
FILE *buffer_tmpfile_rewind(struct line_buffer *buf); /* prepare to write. */
long buffer_tmpfile_prepare_to_read(struct line_buffer *buf);
vcs-svn: allow input errors to be detected promptly The line_buffer library silently flags input errors until buffer_deinit time; unfortunately, by that point usually errno is invalid. Expose the error flag so callers can check for and report errors early for easy debugging. some_error_prone_operation(...); if (buffer_ferror(buf)) return error("input error: %s", strerror(errno)); Signed-off-by: Jonathan Nieder <jrnieder@gmail.com> Signed-off-by: David Barr <david.barr@cordelta.com> Signed-off-by: Jonathan Nieder <jrnieder@gmail.com>
2010-10-11 04:51:21 +02:00
int buffer_ferror(struct line_buffer *buf);
vcs-svn: teach line_buffer to handle multiple input files Collect the line_buffer state in a newly public line_buffer struct. Callers can use multiple line_buffers to manage input from multiple files at a time. svn-fe's delta applier will use this to stream a delta from svnrdump and the preimage it applies to from fast-import at the same time. The tests don't take advantage of the new features, but I think that's okay. It is easier to find lingering examples of nonreentrant code by searching for "static" in line_buffer.c. Signed-off-by: Jonathan Nieder <jrnieder@gmail.com>
2010-10-11 04:41:06 +02:00
char *buffer_read_line(struct line_buffer *buf);
vcs-svn: allow character-oriented input buffer_read_char can be used in place of buffer_read_string(1) to avoid consuming valuable static buffer space. The delta applier will use this to read variable-length integers one byte at a time. Underneath, it is fgetc, wrapped so the line_buffer library can maintain its role as gatekeeper of input. Later it might be worth checking if fgetc_unlocked is faster --- most line_buffer functions are not thread-safe anyway. Helpd-by: David Barr <david.barr@cordelta.com> Signed-off-by: Jonathan Nieder <jrnieder@gmail.com>
2011-01-03 04:06:32 +01:00
int buffer_read_char(struct line_buffer *buf);
vcs-svn: make buffer_read_binary API more convenient buffer_read_binary is a thin wrapper around fread, but its signature is wrong: - fread can fill an arbitrary in-memory buffer. buffer_read_binary is limited to buffers whose size is representable by a 32-bit integer. - The result from fread is the number of bytes actually read. buffer_read_binary only reports the number of bytes read by incrementing sb->len by that amount and returns void. Fix both: let buffer_read_binary accept a size_t instead of uint32_t for the number of bytes to read and as a convenience return the number of bytes actually read. Signed-off-by: Jonathan Nieder <jrnieder@gmail.com> Signed-off-by: David Barr <david.barr@cordelta.com> Signed-off-by: Jonathan Nieder <jrnieder@gmail.com>
2011-01-03 04:37:36 +01:00
size_t buffer_read_binary(struct line_buffer *buf, struct strbuf *sb, size_t len);
vcs-svn: make buffer_copy_bytes return length read Currently buffer_copy_bytes does not report to its caller whether it encountered an early end of file. Add a return value representing the number of bytes read (but not the number of bytes copied). This way all three unusual conditions can be distinguished: input error with buffer_ferror, output error with ferror(outfile), early end of input by checking the return value. Signed-off-by: Jonathan Nieder <jrnieder@gmail.com> Signed-off-by: David Barr <david.barr@cordelta.com> Signed-off-by: Jonathan Nieder <jrnieder@gmail.com>
2010-12-28 11:26:17 +01:00
/* Returns number of bytes read (not necessarily written). */
off_t buffer_copy_bytes(struct line_buffer *buf, off_t len);
vcs-svn: make buffer_skip_bytes return length read Currently there is no way to detect when input ended if it ended early during buffer_skip_bytes. Tell the calling program how many bytes were actually skipped for easier debugging. Existing callers will still ignore early EOF. Signed-off-by: Jonathan Nieder <jrnieder@gmail.com> Signed-off-by: David Barr <david.barr@cordelta.com> Signed-off-by: Jonathan Nieder <jrnieder@gmail.com>
2010-10-11 04:44:21 +02:00
off_t buffer_skip_bytes(struct line_buffer *buf, off_t len);
Add stream helper library This library provides thread-unsafe fgets()- and fread()-like functions where the caller does not have to supply a buffer. It maintains a couple of static buffers and provides an API to use them. [rr: allow input from files other than stdin] [jn: with tests, documentation, and error handling improvements] Signed-off-by: David Barr <david.barr@cordelta.com> Signed-off-by: Ramkumar Ramachandra <artagnon@gmail.com> Signed-off-by: Jonathan Nieder <jrnieder@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2010-08-10 00:39:43 +02:00
#endif
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