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git/line-range.c
Isabella Stephens 96cfa94e68 blame: prevent error if range ends past end of file
If the -L option is used to specify a line range in git blame, and the
end of the range is past the end of the file, git will fail with a fatal
error. This commit prevents such behavior - instead we display the blame
for existing lines within the specified range. Tests are amended
accordingly.

This commit also fixes two corner cases. Blaming -L n,-(n+1) now blames
the first n lines of a file rather than from n to the end of the file.
Blaming -L ,-n will be treated as -L 1,-n and blame the first line of
the file, rather than blaming the whole file.

Signed-off-by: Isabella Stephens <istephens@atlassian.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2018-06-15 10:29:13 -07:00

289 lines
6.5 KiB
C

#include "git-compat-util.h"
#include "line-range.h"
#include "xdiff-interface.h"
#include "strbuf.h"
#include "userdiff.h"
/*
* Parse one item in the -L option
*
* 'begin' is applicable only to relative range anchors. Absolute anchors
* ignore this value.
*
* When parsing "-L A,B", parse_loc() is called once for A and once for B.
*
* When parsing A, 'begin' must be a negative number, the absolute value of
* which is the line at which relative start-of-range anchors should be
* based. Beginning of file is represented by -1.
*
* When parsing B, 'begin' must be the positive line number immediately
* following the line computed for 'A'.
*/
static const char *parse_loc(const char *spec, nth_line_fn_t nth_line,
void *data, long lines, long begin, long *ret)
{
char *term;
const char *line;
long num;
int reg_error;
regex_t regexp;
regmatch_t match[1];
/* Allow "-L <something>,+20" to mean starting at <something>
* for 20 lines, or "-L <something>,-5" for 5 lines ending at
* <something>.
*/
if (1 <= begin && (spec[0] == '+' || spec[0] == '-')) {
num = strtol(spec + 1, &term, 10);
if (term != spec + 1) {
if (!ret)
return term;
if (num == 0)
die("-L invalid empty range");
if (spec[0] == '-')
num = 0 - num;
if (0 < num)
*ret = begin + num - 2;
else if (!num)
*ret = begin;
else
*ret = begin + num > 0 ? begin + num : 1;
return term;
}
return spec;
}
num = strtol(spec, &term, 10);
if (term != spec) {
if (ret) {
if (num <= 0)
die("-L invalid line number: %ld", num);
*ret = num;
}
return term;
}
if (begin < 0) {
if (spec[0] != '^')
begin = -begin;
else {
begin = 1;
spec++;
}
}
if (spec[0] != '/')
return spec;
/* it could be a regexp of form /.../ */
for (term = (char *) spec + 1; *term && *term != '/'; term++) {
if (*term == '\\')
term++;
}
if (*term != '/')
return spec;
/* in the scan-only case we are not interested in the regex */
if (!ret)
return term+1;
/* try [spec+1 .. term-1] as regexp */
*term = 0;
begin--; /* input is in human terms */
line = nth_line(data, begin);
if (!(reg_error = regcomp(&regexp, spec + 1, REG_NEWLINE)) &&
!(reg_error = regexec(&regexp, line, 1, match, 0))) {
const char *cp = line + match[0].rm_so;
const char *nline;
while (begin++ < lines) {
nline = nth_line(data, begin);
if (line <= cp && cp < nline)
break;
line = nline;
}
*ret = begin;
regfree(&regexp);
*term++ = '/';
return term;
}
else {
char errbuf[1024];
regerror(reg_error, &regexp, errbuf, 1024);
die("-L parameter '%s' starting at line %ld: %s",
spec + 1, begin + 1, errbuf);
}
}
static int match_funcname(xdemitconf_t *xecfg, const char *bol, const char *eol)
{
if (xecfg) {
char buf[1];
return xecfg->find_func(bol, eol - bol, buf, 1,
xecfg->find_func_priv) >= 0;
}
if (bol == eol)
return 0;
if (isalpha(*bol) || *bol == '_' || *bol == '$')
return 1;
return 0;
}
static const char *find_funcname_matching_regexp(xdemitconf_t *xecfg, const char *start,
regex_t *regexp)
{
int reg_error;
regmatch_t match[1];
while (1) {
const char *bol, *eol;
reg_error = regexec(regexp, start, 1, match, 0);
if (reg_error == REG_NOMATCH)
return NULL;
else if (reg_error) {
char errbuf[1024];
regerror(reg_error, regexp, errbuf, 1024);
die("-L parameter: regexec() failed: %s", errbuf);
}
/* determine extent of line matched */
bol = start+match[0].rm_so;
eol = start+match[0].rm_eo;
while (bol > start && *bol != '\n')
bol--;
if (*bol == '\n')
bol++;
while (*eol && *eol != '\n')
eol++;
if (*eol == '\n')
eol++;
/* is it a funcname line? */
if (match_funcname(xecfg, (char*) bol, (char*) eol))
return bol;
start = eol;
}
}
static const char *parse_range_funcname(const char *arg, nth_line_fn_t nth_line_cb,
void *cb_data, long lines, long anchor, long *begin, long *end,
const char *path)
{
char *pattern;
const char *term;
struct userdiff_driver *drv;
xdemitconf_t *xecfg = NULL;
const char *start;
const char *p;
int reg_error;
regex_t regexp;
if (*arg == '^') {
anchor = 1;
arg++;
}
assert(*arg == ':');
term = arg+1;
while (*term && *term != ':') {
if (*term == '\\' && *(term+1))
term++;
term++;
}
if (term == arg+1)
return NULL;
if (!begin) /* skip_range_arg case */
return term;
pattern = xstrndup(arg+1, term-(arg+1));
anchor--; /* input is in human terms */
start = nth_line_cb(cb_data, anchor);
drv = userdiff_find_by_path(path);
if (drv && drv->funcname.pattern) {
const struct userdiff_funcname *pe = &drv->funcname;
xecfg = xcalloc(1, sizeof(*xecfg));
xdiff_set_find_func(xecfg, pe->pattern, pe->cflags);
}
reg_error = regcomp(&regexp, pattern, REG_NEWLINE);
if (reg_error) {
char errbuf[1024];
regerror(reg_error, &regexp, errbuf, 1024);
die("-L parameter '%s': %s", pattern, errbuf);
}
p = find_funcname_matching_regexp(xecfg, (char*) start, &regexp);
if (!p)
die("-L parameter '%s' starting at line %ld: no match",
pattern, anchor + 1);
*begin = 0;
while (p > nth_line_cb(cb_data, *begin))
(*begin)++;
if (*begin >= lines)
die("-L parameter '%s' matches at EOF", pattern);
*end = *begin+1;
while (*end < lines) {
const char *bol = nth_line_cb(cb_data, *end);
const char *eol = nth_line_cb(cb_data, *end+1);
if (match_funcname(xecfg, bol, eol))
break;
(*end)++;
}
regfree(&regexp);
free(xecfg);
free(pattern);
/* compensate for 1-based numbering */
(*begin)++;
return term;
}
int parse_range_arg(const char *arg, nth_line_fn_t nth_line_cb,
void *cb_data, long lines, long anchor,
long *begin, long *end, const char *path)
{
*begin = *end = 0;
if (anchor < 1)
anchor = 1;
if (anchor > lines)
anchor = lines + 1;
if (*arg == ':' || (*arg == '^' && *(arg + 1) == ':')) {
arg = parse_range_funcname(arg, nth_line_cb, cb_data, lines, anchor, begin, end, path);
if (!arg || *arg)
return -1;
return 0;
}
arg = parse_loc(arg, nth_line_cb, cb_data, lines, -anchor, begin);
if (*arg == ',')
arg = parse_loc(arg + 1, nth_line_cb, cb_data, lines, *begin + 1, end);
if (*arg)
return -1;
if (*begin && *end && *end < *begin) {
SWAP(*end, *begin);
}
return 0;
}
const char *skip_range_arg(const char *arg)
{
if (*arg == ':' || (*arg == '^' && *(arg + 1) == ':'))
return parse_range_funcname(arg, NULL, NULL, 0, 0, NULL, NULL, NULL);
arg = parse_loc(arg, NULL, NULL, 0, -1, NULL);
if (*arg == ',')
arg = parse_loc(arg+1, NULL, NULL, 0, 0, NULL);
return arg;
}