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use skip_prefix to avoid magic numbers

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It's a common idiom to match a prefix and then skip past it
with a magic number, like:

  if (starts_with(foo, "bar"))
	  foo += 3;

This is easy to get wrong, since you have to count the
prefix string yourself, and there's no compiler check if the
string changes.  We can use skip_prefix to avoid the magic
numbers here.

Note that some of these conversions could be much shorter.
For example:

  if (starts_with(arg, "--foo=")) {
	  bar = arg + 6;
	  continue;
  }

could become:

  if (skip_prefix(arg, "--foo=", &bar))
	  continue;

However, I have left it as:

  if (skip_prefix(arg, "--foo=", &v)) {
	  bar = v;
	  continue;
  }

to visually match nearby cases which need to actually
process the string. Like:

  if (skip_prefix(arg, "--foo=", &v)) {
	  bar = atoi(v);
	  continue;
  }

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
This commit is contained in:
Jeff King
2014-06-18 15:47:50 -04:00
committed by Junio C Hamano
parent 21a2d4ada5
commit ae021d8791
11 changed files with 149 additions and 131 deletions
Download Patch File Download Diff File Expand all files Collapse all files

65
diff.c
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@ -231,6 +231,8 @@ int git_diff_ui_config(const char *var, const char *value, void *cb)
int git_diff_basic_config(const char *var, const char *value, void *cb)
{
const char *name;
if (!strcmp(var, "diff.renamelimit")) {
diff_rename_limit_default = git_config_int(var, value);
return 0;
@ -239,8 +241,9 @@ int git_diff_basic_config(const char *var, const char *value, void *cb)
if (userdiff_config(var, value) < 0)
return -1;
if (starts_with(var, "diff.color.") || starts_with(var, "color.diff.")) {
int slot = parse_diff_color_slot(var + 11);
if (skip_prefix(var, "diff.color.", &name) ||
skip_prefix(var, "color.diff.", &name)) {
int slot = parse_diff_color_slot(name);
if (slot < 0)
return 0;
if (!value)
@ -2341,6 +2344,7 @@ static void builtin_diff(const char *name_a,
} else {
/* Crazy xdl interfaces.. */
const char *diffopts = getenv("GIT_DIFF_OPTS");
const char *v;
xpparam_t xpp;
xdemitconf_t xecfg;
struct emit_callback ecbdata;
@ -2379,10 +2383,10 @@ static void builtin_diff(const char *name_a,
xdiff_set_find_func(&xecfg, pe->pattern, pe->cflags);
if (!diffopts)
;
else if (starts_with(diffopts, "--unified="))
xecfg.ctxlen = strtoul(diffopts + 10, NULL, 10);
else if (starts_with(diffopts, "-u"))
xecfg.ctxlen = strtoul(diffopts + 2, NULL, 10);
else if (skip_prefix(diffopts, "--unified=", &v))
xecfg.ctxlen = strtoul(v, NULL, 10);
else if (skip_prefix(diffopts, "-u", &v))
xecfg.ctxlen = strtoul(v, NULL, 10);
if (o->word_diff)
init_diff_words_data(&ecbdata, o, one, two);
xdi_diff_outf(&mf1, &mf2, fn_out_consume, &ecbdata,
@ -3609,17 +3613,17 @@ int diff_opt_parse(struct diff_options *options, const char **av, int ac)
options->output_format |= DIFF_FORMAT_SHORTSTAT;
else if (!strcmp(arg, "-X") || !strcmp(arg, "--dirstat"))
return parse_dirstat_opt(options, "");
else if (starts_with(arg, "-X"))
return parse_dirstat_opt(options, arg + 2);
else if (starts_with(arg, "--dirstat="))
return parse_dirstat_opt(options, arg + 10);
else if (skip_prefix(arg, "-X", &arg))
return parse_dirstat_opt(options, arg);
else if (skip_prefix(arg, "--dirstat=", &arg))
return parse_dirstat_opt(options, arg);
else if (!strcmp(arg, "--cumulative"))
return parse_dirstat_opt(options, "cumulative");
else if (!strcmp(arg, "--dirstat-by-file"))
return parse_dirstat_opt(options, "files");
else if (starts_with(arg, "--dirstat-by-file=")) {
else if (skip_prefix(arg, "--dirstat-by-file=", &arg)) {
parse_dirstat_opt(options, "files");
return parse_dirstat_opt(options, arg + 18);
return parse_dirstat_opt(options, arg);
}
else if (!strcmp(arg, "--check"))
options->output_format |= DIFF_FORMAT_CHECKDIFF;
@ -3669,9 +3673,9 @@ int diff_opt_parse(struct diff_options *options, const char **av, int ac)
DIFF_OPT_CLR(options, RENAME_EMPTY);
else if (!strcmp(arg, "--relative"))
DIFF_OPT_SET(options, RELATIVE_NAME);
else if (starts_with(arg, "--relative=")) {
else if (skip_prefix(arg, "--relative=", &arg)) {
DIFF_OPT_SET(options, RELATIVE_NAME);
options->prefix = arg + 11;
options->prefix = arg;
}
/* xdiff options */
@ -3722,8 +3726,8 @@ int diff_opt_parse(struct diff_options *options, const char **av, int ac)
DIFF_OPT_CLR(options, FOLLOW_RENAMES);
else if (!strcmp(arg, "--color"))
options->use_color = 1;
else if (starts_with(arg, "--color=")) {
int value = git_config_colorbool(NULL, arg+8);
else if (skip_prefix(arg, "--color=", &arg)) {
int value = git_config_colorbool(NULL, arg);
if (value < 0)
return error("option `color' expects \"always\", \"auto\", or \"never\"");
options->use_color = value;
@ -3734,29 +3738,28 @@ int diff_opt_parse(struct diff_options *options, const char **av, int ac)
options->use_color = 1;
options->word_diff = DIFF_WORDS_COLOR;
}
else if (starts_with(arg, "--color-words=")) {
else if (skip_prefix(arg, "--color-words=", &arg)) {
options->use_color = 1;
options->word_diff = DIFF_WORDS_COLOR;
options->word_regex = arg + 14;
options->word_regex = arg;
}
else if (!strcmp(arg, "--word-diff")) {
if (options->word_diff == DIFF_WORDS_NONE)
options->word_diff = DIFF_WORDS_PLAIN;
}
else if (starts_with(arg, "--word-diff=")) {
const char *type = arg + 12;
if (!strcmp(type, "plain"))
else if (skip_prefix(arg, "--word-diff=", &arg)) {
if (!strcmp(arg, "plain"))
options->word_diff = DIFF_WORDS_PLAIN;
else if (!strcmp(type, "color")) {
else if (!strcmp(arg, "color")) {
options->use_color = 1;
options->word_diff = DIFF_WORDS_COLOR;
}
else if (!strcmp(type, "porcelain"))
else if (!strcmp(arg, "porcelain"))
options->word_diff = DIFF_WORDS_PORCELAIN;
else if (!strcmp(type, "none"))
else if (!strcmp(arg, "none"))
options->word_diff = DIFF_WORDS_NONE;
else
die("bad --word-diff argument: %s", type);
die("bad --word-diff argument: %s", arg);
}
else if ((argcount = parse_long_opt("word-diff-regex", av, &optarg))) {
if (options->word_diff == DIFF_WORDS_NONE)
@ -3779,13 +3782,13 @@ int diff_opt_parse(struct diff_options *options, const char **av, int ac)
else if (!strcmp(arg, "--ignore-submodules")) {
DIFF_OPT_SET(options, OVERRIDE_SUBMODULE_CONFIG);
handle_ignore_submodules_arg(options, "all");
} else if (starts_with(arg, "--ignore-submodules=")) {
} else if (skip_prefix(arg, "--ignore-submodules=", &arg)) {
DIFF_OPT_SET(options, OVERRIDE_SUBMODULE_CONFIG);
handle_ignore_submodules_arg(options, arg + 20);
handle_ignore_submodules_arg(options, arg);
} else if (!strcmp(arg, "--submodule"))
DIFF_OPT_SET(options, SUBMODULE_LOG);
else if (starts_with(arg, "--submodule="))
return parse_submodule_opt(options, arg + 12);
else if (skip_prefix(arg, "--submodule=", &arg))
return parse_submodule_opt(options, arg);
/* misc options */
else if (!strcmp(arg, "-z"))
@ -3820,8 +3823,8 @@ int diff_opt_parse(struct diff_options *options, const char **av, int ac)
}
else if (!strcmp(arg, "--abbrev"))
options->abbrev = DEFAULT_ABBREV;
else if (starts_with(arg, "--abbrev=")) {
options->abbrev = strtoul(arg + 9, NULL, 10);
else if (skip_prefix(arg, "--abbrev=", &arg)) {
options->abbrev = strtoul(arg, NULL, 10);
if (options->abbrev < MINIMUM_ABBREV)
options->abbrev = MINIMUM_ABBREV;
else if (40 < options->abbrev)