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-rw-r--r--completions/bfs.bash3
-rw-r--r--completions/bfs.fish1
-rw-r--r--completions/bfs.zsh1
-rw-r--r--docs/USAGE.md34
-rw-r--r--docs/bfs.15
-rw-r--r--src/eval.c13
-rw-r--r--src/eval.h1
-rw-r--r--src/opt.c1
-rw-r--r--src/parse.c38
-rw-r--r--tests/bfs/limit.out4
-rw-r--r--tests/bfs/limit.sh1
-rw-r--r--tests/bfs/limit_0.sh1
-rw-r--r--tests/bfs/limit_implicit_print.sh1
-rw-r--r--tests/bfs/limit_incomplete.sh1
-rw-r--r--tests/bfs/limit_one.sh1
15 files changed, 103 insertions, 3 deletions
diff --git a/completions/bfs.bash b/completions/bfs.bash
index 2f52e8d..db582da 100644
--- a/completions/bfs.bash
+++ b/completions/bfs.bash
@@ -37,6 +37,7 @@ _bfs() {
-ipath
-iregex
-iwholename
+ -limit
-links
-lname
-maxdepth
@@ -94,8 +95,6 @@ _bfs() {
-depth
-follow
-ignore_readdir_race
- -maxdepth
- -mindepth
-mount
-nocolor
-noignore_readdir_race
diff --git a/completions/bfs.fish b/completions/bfs.fish
index 3f399e7..1303639 100644
--- a/completions/bfs.fish
+++ b/completions/bfs.fish
@@ -133,6 +133,7 @@ complete -c bfs -o fls -d "Like -ls, but write to specified file" -F
complete -c bfs -o fprint -d "Like -print, but write to specified file" -F
complete -c bfs -o fprint0 -d "Like -print0, but write to specified file" -F
complete -c bfs -o fprintf -d "Like -printf, but write to specified file" -F
+complete -c bfs -o limit -d "Limit the number of results" -x
complete -c bfs -o ls -d "List files like ls -dils"
complete -c bfs -o print -d "Print the path to the found file"
complete -c bfs -o print0 -d "Like -print, but use the null character as a separator rather than newlines"
diff --git a/completions/bfs.zsh b/completions/bfs.zsh
index 3d7dc3a..51b5029 100644
--- a/completions/bfs.zsh
+++ b/completions/bfs.zsh
@@ -133,6 +133,7 @@ args=(
'*-fprint0[print the path to the found file using null character as separator, but write to FILE instead of standard output]:output file:_files'
'*-fprintf[print according to format string, but write to FILE instead of standard output]:output file:_files:output format'
+ '*-limit[quit after N results]:maximum result count'
'*-ls[list files like ls -dils]'
'*-print[print the path to the found file]'
'*-print0[print the path to the found file using null character as separator]'
diff --git a/docs/USAGE.md b/docs/USAGE.md
index 3efdee0..071c95b 100644
--- a/docs/USAGE.md
+++ b/docs/USAGE.md
@@ -130,6 +130,40 @@ Unlike `-prune`, `-exclude` even works in combination with `-depth`/`-delete`.
---
+### `-limit`
+
+The `-limit N` action makes `bfs` quit once it gets evaluated `N` times.
+Placing it after an action like `-print` limits the number of results that get printed, for example:
+
+```console
+$ bfs -s -type f -name '*.txt'
+./1.txt
+./2.txt
+./3.txt
+./4.txt
+$ bfs -s -type f -name '*.txt' -print -limit 2
+./1.txt
+./2.txt
+```
+
+This is similar to
+
+```console
+$ bfs -s -type f -name '*.txt' | head -n2
+```
+
+but more powerful because you can apply separate limits to different expressions:
+
+```console
+$ bfs \( -name '*.txt' -print -limit 3 -o -name '*.log' -print -limit 4 \) -limit 5
+[At most 3 .txt files, at most 4 .log files, and at most 5 in total]
+```
+
+and more efficient because it will quit immediately.
+When piping to `head`, `bfs` will only quit *after* it tries to output too many results.
+
+---
+
### `-hidden`/`-nohidden`
`-hidden` matches "hidden" files (dotfiles).
diff --git a/docs/bfs.1 b/docs/bfs.1
index 2ecb891..3a4f15a 100644
--- a/docs/bfs.1
+++ b/docs/bfs.1
@@ -725,6 +725,11 @@ but write to
instead of standard output.
.RE
.TP
+\fB\-limit \fIN\fR
+Quit once this action is evaluated
+.I N
+times.
+.TP
.B \-ls
List files like
.B ls
diff --git a/src/eval.c b/src/eval.c
index 9e55964..2f06858 100644
--- a/src/eval.c
+++ b/src/eval.c
@@ -841,6 +841,19 @@ error:
}
/**
+ * -limit action.
+ */
+bool eval_limit(const struct bfs_expr *expr, struct bfs_eval *state) {
+ long long evals = expr->evaluations + 1;
+ if (evals >= expr->num) {
+ state->action = BFTW_STOP;
+ state->quit = true;
+ }
+
+ return true;
+}
+
+/**
* -prune action.
*/
bool eval_prune(const struct bfs_expr *expr, struct bfs_eval *state) {
diff --git a/src/eval.h b/src/eval.h
index 98bbc08..f7f6c77 100644
--- a/src/eval.h
+++ b/src/eval.h
@@ -88,6 +88,7 @@ bool eval_fprint(const struct bfs_expr *expr, struct bfs_eval *state);
bool eval_fprint0(const struct bfs_expr *expr, struct bfs_eval *state);
bool eval_fprintf(const struct bfs_expr *expr, struct bfs_eval *state);
bool eval_fprintx(const struct bfs_expr *expr, struct bfs_eval *state);
+bool eval_limit(const struct bfs_expr *expr, struct bfs_eval *state);
bool eval_prune(const struct bfs_expr *expr, struct bfs_eval *state);
bool eval_quit(const struct bfs_expr *expr, struct bfs_eval *state);
diff --git a/src/opt.c b/src/opt.c
index 76965de..a470d25 100644
--- a/src/opt.c
+++ b/src/opt.c
@@ -1181,6 +1181,7 @@ static struct bfs_expr *annotate_visit(struct bfs_opt *opt, struct bfs_expr *exp
eval_fprint0,
eval_fprintf,
eval_fprintx,
+ eval_limit,
eval_prune,
eval_true,
// Non-returning
diff --git a/src/parse.c b/src/parse.c
index 3b7386d..2dfcab2 100644
--- a/src/parse.c
+++ b/src/parse.c
@@ -97,6 +97,8 @@ struct bfs_parser {
char **last_arg;
/** A "-depth"-type argument, if any. */
char **depth_arg;
+ /** A "-limit" argument, if any. */
+ char **limit_arg;
/** A "-prune" argument, if any. */
char **prune_arg;
/** A "-mount" argument, if any. */
@@ -733,7 +735,7 @@ static struct bfs_expr *parse_action(struct bfs_parser *parser, bfs_eval_fn *eva
return NULL;
}
- if (eval_fn != eval_prune && eval_fn != eval_quit) {
+ if (eval_fn != eval_limit && eval_fn != eval_prune && eval_fn != eval_quit) {
parser->implicit_print = false;
}
@@ -1570,6 +1572,29 @@ static struct bfs_expr *parse_jobs(struct bfs_parser *parser, int arg1, int arg2
}
/**
+ * Parse -limit N.
+ */
+static struct bfs_expr *parse_limit(struct bfs_parser *parser, int arg1, int arg2) {
+ struct bfs_expr *expr = parse_unary_action(parser, eval_limit);
+ if (!expr) {
+ return NULL;
+ }
+
+ char **arg = &expr->argv[1];
+ if (!parse_int(parser, arg, *arg, &expr->num, IF_LONG_LONG)) {
+ return NULL;
+ }
+
+ if (expr->num <= 0) {
+ parse_expr_error(parser, expr, "The ${blu}%s${rs} must be at least ${bld}1${rs}.\n", expr->argv[0]);
+ return NULL;
+ }
+
+ parser->limit_arg = expr->argv;
+ return expr;
+}
+
+/**
* Parse -links N.
*/
static struct bfs_expr *parse_links(struct bfs_parser *parser, int arg1, int arg2) {
@@ -2845,6 +2870,8 @@ static struct bfs_expr *parse_help(struct bfs_parser *parser, int arg1, int arg2
cfprintf(cout, " ${blu}-fprintf${rs} ${bld}FILE${rs} ${bld}FORMAT${rs}\n");
cfprintf(cout, " Like ${blu}-ls${rs}/${blu}-print${rs}/${blu}-print0${rs}/${blu}-printf${rs}, but write to ${bld}FILE${rs} instead of standard\n"
" output\n");
+ cfprintf(cout, " ${blu}-limit${rs} ${bld}N${rs}\n");
+ cfprintf(cout, " Quit after this action is evaluated ${bld}N${rs} times\n");
cfprintf(cout, " ${blu}-ls${rs}\n");
cfprintf(cout, " List files like ${ex}ls${rs} ${bld}-dils${rs}\n");
cfprintf(cout, " ${blu}-print${rs}\n");
@@ -2968,6 +2995,7 @@ static const struct table_entry parse_table[] = {
{"-iregex", T_TEST, parse_regex, BFS_REGEX_ICASE},
{"-iwholename", T_TEST, parse_path, true},
{"-j", T_FLAG, parse_jobs, 0, 0, true},
+ {"-limit", T_ACTION, parse_limit},
{"-links", T_TEST, parse_links},
{"-lname", T_TEST, parse_lname, false},
{"-ls", T_ACTION, parse_ls},
@@ -3330,6 +3358,14 @@ static struct bfs_expr *parse_whole_expr(struct bfs_parser *parser) {
}
if (parser->implicit_print) {
+ char **limit = parser->limit_arg;
+ if (limit) {
+ parse_argv_error(parser, parser->limit_arg, 2,
+ "With ${blu}%s${rs}, you must specify an action explicitly; for example, ${blu}-print${rs} ${blu}%s${rs} ${bld}%s${rs}.\n",
+ limit[0], limit[0], limit[1]);
+ return NULL;
+ }
+
struct bfs_expr *print = parse_new_expr(parser, eval_fprint, 1, &fake_print_arg);
if (!print) {
return NULL;
diff --git a/tests/bfs/limit.out b/tests/bfs/limit.out
new file mode 100644
index 0000000..ea94276
--- /dev/null
+++ b/tests/bfs/limit.out
@@ -0,0 +1,4 @@
+basic/a
+basic/b
+basic/c/d
+basic/e/f
diff --git a/tests/bfs/limit.sh b/tests/bfs/limit.sh
new file mode 100644
index 0000000..84b605f
--- /dev/null
+++ b/tests/bfs/limit.sh
@@ -0,0 +1 @@
+bfs_diff -s basic -type f -print -limit 4
diff --git a/tests/bfs/limit_0.sh b/tests/bfs/limit_0.sh
new file mode 100644
index 0000000..3ce26de
--- /dev/null
+++ b/tests/bfs/limit_0.sh
@@ -0,0 +1 @@
+! invoke_bfs basic -print -limit 0
diff --git a/tests/bfs/limit_implicit_print.sh b/tests/bfs/limit_implicit_print.sh
new file mode 100644
index 0000000..cdb059d
--- /dev/null
+++ b/tests/bfs/limit_implicit_print.sh
@@ -0,0 +1 @@
+! invoke_bfs basic -type f -limit 1
diff --git a/tests/bfs/limit_incomplete.sh b/tests/bfs/limit_incomplete.sh
new file mode 100644
index 0000000..2d1e842
--- /dev/null
+++ b/tests/bfs/limit_incomplete.sh
@@ -0,0 +1 @@
+! invoke_bfs basic -print -limit
diff --git a/tests/bfs/limit_one.sh b/tests/bfs/limit_one.sh
new file mode 100644
index 0000000..3f8181c
--- /dev/null
+++ b/tests/bfs/limit_one.sh
@@ -0,0 +1 @@
+! invoke_bfs basic -print -limit one