aboutsummaryrefslogtreecommitdiff
diff options
context:
space:
mode:
authorGravatar Benjamin Barenblat <bbaren@google.com>2019-09-16 11:04:19 -0400
committerGravatar Benjamin Barenblat <bbaren@google.com>2019-09-16 11:04:19 -0400
commit82cd3de3f4acb0e7a19ebec91baa0eba0d23bd9b (patch)
tree5892d9ec381c713fd2b28685c055f8d8438b909f
walk and sor, a combined replacement for find
-rw-r--r--.gitignore8
-rw-r--r--LICENSE202
-rw-r--r--Makefile21
-rw-r--r--README.md69
-rwxr-xr-xsor23
-rw-r--r--sor.131
-rw-r--r--walk.130
-rw-r--r--walk.c99
8 files changed, 483 insertions, 0 deletions
diff --git a/.gitignore b/.gitignore
new file mode 100644
index 0000000..7a212a1
--- /dev/null
+++ b/.gitignore
@@ -0,0 +1,8 @@
+# Editor backup files
+*~
+\#*
+.\#*
+.*.swp
+
+# Build artifacts
+walk \ No newline at end of file
diff --git a/LICENSE b/LICENSE
new file mode 100644
index 0000000..d645695
--- /dev/null
+++ b/LICENSE
@@ -0,0 +1,202 @@
+
+ Apache License
+ Version 2.0, January 2004
+ http://www.apache.org/licenses/
+
+ TERMS AND CONDITIONS FOR USE, REPRODUCTION, AND DISTRIBUTION
+
+ 1. Definitions.
+
+ "License" shall mean the terms and conditions for use, reproduction,
+ and distribution as defined by Sections 1 through 9 of this document.
+
+ "Licensor" shall mean the copyright owner or entity authorized by
+ the copyright owner that is granting the License.
+
+ "Legal Entity" shall mean the union of the acting entity and all
+ other entities that control, are controlled by, or are under common
+ control with that entity. For the purposes of this definition,
+ "control" means (i) the power, direct or indirect, to cause the
+ direction or management of such entity, whether by contract or
+ otherwise, or (ii) ownership of fifty percent (50%) or more of the
+ outstanding shares, or (iii) beneficial ownership of such entity.
+
+ "You" (or "Your") shall mean an individual or Legal Entity
+ exercising permissions granted by this License.
+
+ "Source" form shall mean the preferred form for making modifications,
+ including but not limited to software source code, documentation
+ source, and configuration files.
+
+ "Object" form shall mean any form resulting from mechanical
+ transformation or translation of a Source form, including but
+ not limited to compiled object code, generated documentation,
+ and conversions to other media types.
+
+ "Work" shall mean the work of authorship, whether in Source or
+ Object form, made available under the License, as indicated by a
+ copyright notice that is included in or attached to the work
+ (an example is provided in the Appendix below).
+
+ "Derivative Works" shall mean any work, whether in Source or Object
+ form, that is based on (or derived from) the Work and for which the
+ editorial revisions, annotations, elaborations, or other modifications
+ represent, as a whole, an original work of authorship. For the purposes
+ of this License, Derivative Works shall not include works that remain
+ separable from, or merely link (or bind by name) to the interfaces of,
+ the Work and Derivative Works thereof.
+
+ "Contribution" shall mean any work of authorship, including
+ the original version of the Work and any modifications or additions
+ to that Work or Derivative Works thereof, that is intentionally
+ submitted to Licensor for inclusion in the Work by the copyright owner
+ or by an individual or Legal Entity authorized to submit on behalf of
+ the copyright owner. For the purposes of this definition, "submitted"
+ means any form of electronic, verbal, or written communication sent
+ to the Licensor or its representatives, including but not limited to
+ communication on electronic mailing lists, source code control systems,
+ and issue tracking systems that are managed by, or on behalf of, the
+ Licensor for the purpose of discussing and improving the Work, but
+ excluding communication that is conspicuously marked or otherwise
+ designated in writing by the copyright owner as "Not a Contribution."
+
+ "Contributor" shall mean Licensor and any individual or Legal Entity
+ on behalf of whom a Contribution has been received by Licensor and
+ subsequently incorporated within the Work.
+
+ 2. Grant of Copyright License. Subject to the terms and conditions of
+ this License, each Contributor hereby grants to You a perpetual,
+ worldwide, non-exclusive, no-charge, royalty-free, irrevocable
+ copyright license to reproduce, prepare Derivative Works of,
+ publicly display, publicly perform, sublicense, and distribute the
+ Work and such Derivative Works in Source or Object form.
+
+ 3. Grant of Patent License. Subject to the terms and conditions of
+ this License, each Contributor hereby grants to You a perpetual,
+ worldwide, non-exclusive, no-charge, royalty-free, irrevocable
+ (except as stated in this section) patent license to make, have made,
+ use, offer to sell, sell, import, and otherwise transfer the Work,
+ where such license applies only to those patent claims licensable
+ by such Contributor that are necessarily infringed by their
+ Contribution(s) alone or by combination of their Contribution(s)
+ with the Work to which such Contribution(s) was submitted. If You
+ institute patent litigation against any entity (including a
+ cross-claim or counterclaim in a lawsuit) alleging that the Work
+ or a Contribution incorporated within the Work constitutes direct
+ or contributory patent infringement, then any patent licenses
+ granted to You under this License for that Work shall terminate
+ as of the date such litigation is filed.
+
+ 4. Redistribution. You may reproduce and distribute copies of the
+ Work or Derivative Works thereof in any medium, with or without
+ modifications, and in Source or Object form, provided that You
+ meet the following conditions:
+
+ (a) You must give any other recipients of the Work or
+ Derivative Works a copy of this License; and
+
+ (b) You must cause any modified files to carry prominent notices
+ stating that You changed the files; and
+
+ (c) You must retain, in the Source form of any Derivative Works
+ that You distribute, all copyright, patent, trademark, and
+ attribution notices from the Source form of the Work,
+ excluding those notices that do not pertain to any part of
+ the Derivative Works; and
+
+ (d) If the Work includes a "NOTICE" text file as part of its
+ distribution, then any Derivative Works that You distribute must
+ include a readable copy of the attribution notices contained
+ within such NOTICE file, excluding those notices that do not
+ pertain to any part of the Derivative Works, in at least one
+ of the following places: within a NOTICE text file distributed
+ as part of the Derivative Works; within the Source form or
+ documentation, if provided along with the Derivative Works; or,
+ within a display generated by the Derivative Works, if and
+ wherever such third-party notices normally appear. The contents
+ of the NOTICE file are for informational purposes only and
+ do not modify the License. You may add Your own attribution
+ notices within Derivative Works that You distribute, alongside
+ or as an addendum to the NOTICE text from the Work, provided
+ that such additional attribution notices cannot be construed
+ as modifying the License.
+
+ You may add Your own copyright statement to Your modifications and
+ may provide additional or different license terms and conditions
+ for use, reproduction, or distribution of Your modifications, or
+ for any such Derivative Works as a whole, provided Your use,
+ reproduction, and distribution of the Work otherwise complies with
+ the conditions stated in this License.
+
+ 5. Submission of Contributions. Unless You explicitly state otherwise,
+ any Contribution intentionally submitted for inclusion in the Work
+ by You to the Licensor shall be under the terms and conditions of
+ this License, without any additional terms or conditions.
+ Notwithstanding the above, nothing herein shall supersede or modify
+ the terms of any separate license agreement you may have executed
+ with Licensor regarding such Contributions.
+
+ 6. Trademarks. This License does not grant permission to use the trade
+ names, trademarks, service marks, or product names of the Licensor,
+ except as required for reasonable and customary use in describing the
+ origin of the Work and reproducing the content of the NOTICE file.
+
+ 7. Disclaimer of Warranty. Unless required by applicable law or
+ agreed to in writing, Licensor provides the Work (and each
+ Contributor provides its Contributions) on an "AS IS" BASIS,
+ WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
+ implied, including, without limitation, any warranties or conditions
+ of TITLE, NON-INFRINGEMENT, MERCHANTABILITY, or FITNESS FOR A
+ PARTICULAR PURPOSE. You are solely responsible for determining the
+ appropriateness of using or redistributing the Work and assume any
+ risks associated with Your exercise of permissions under this License.
+
+ 8. Limitation of Liability. In no event and under no legal theory,
+ whether in tort (including negligence), contract, or otherwise,
+ unless required by applicable law (such as deliberate and grossly
+ negligent acts) or agreed to in writing, shall any Contributor be
+ liable to You for damages, including any direct, indirect, special,
+ incidental, or consequential damages of any character arising as a
+ result of this License or out of the use or inability to use the
+ Work (including but not limited to damages for loss of goodwill,
+ work stoppage, computer failure or malfunction, or any and all
+ other commercial damages or losses), even if such Contributor
+ has been advised of the possibility of such damages.
+
+ 9. Accepting Warranty or Additional Liability. While redistributing
+ the Work or Derivative Works thereof, You may choose to offer,
+ and charge a fee for, acceptance of support, warranty, indemnity,
+ or other liability obligations and/or rights consistent with this
+ License. However, in accepting such obligations, You may act only
+ on Your own behalf and on Your sole responsibility, not on behalf
+ of any other Contributor, and only if You agree to indemnify,
+ defend, and hold each Contributor harmless for any liability
+ incurred by, or claims asserted against, such Contributor by reason
+ of your accepting any such warranty or additional liability.
+
+ END OF TERMS AND CONDITIONS
+
+ APPENDIX: How to apply the Apache License to your work.
+
+ To apply the Apache License to your work, attach the following
+ boilerplate notice, with the fields enclosed by brackets "[]"
+ replaced with your own identifying information. (Don't include
+ the brackets!) The text should be enclosed in the appropriate
+ comment syntax for the file format. We also recommend that a
+ file or class name and description of purpose be included on the
+ same "printed page" as the copyright notice for easier
+ identification within third-party archives.
+
+ Copyright [yyyy] [name of copyright owner]
+
+ Licensed under the Apache License, Version 2.0 (the "License");
+ you may not use this file except in compliance with the License.
+ You may obtain a copy of the License at
+
+ http://www.apache.org/licenses/LICENSE-2.0
+
+ Unless required by applicable law or agreed to in writing, software
+ distributed under the License is distributed on an "AS IS" BASIS,
+ WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ See the License for the specific language governing permissions and
+ limitations under the License.
diff --git a/Makefile b/Makefile
new file mode 100644
index 0000000..b768764
--- /dev/null
+++ b/Makefile
@@ -0,0 +1,21 @@
+# Copyright 2019 Google LLC
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+# https://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+CFLAGS = -Wall -O2
+
+.DEFAULT_GOAL := walk
+
+.PHONY: clean
+clean:
+ $(RM) walk
diff --git a/README.md b/README.md
new file mode 100644
index 0000000..1d913ac
--- /dev/null
+++ b/README.md
@@ -0,0 +1,69 @@
+`walk` and `sor`
+================
+
+This repository contains `walk` and `sor`, two utility programs that
+collectively replace [`find`][find]. `walk` recursively walks the directories
+specified on the command line (or the current directory, if none is specified),
+printing each file path. `sor` (“shell or”) reads file paths from standard
+input; for each path, it evaluates its arguments as Bash snippets, passing the
+path as an argument to each and printing the path if any snippet exits with
+status 0. For example, instead of saying
+
+ find . -type f -name \*foo\*
+
+you can say
+
+ walk | grep foo | sor 'test -f'
+
+[find]: https://pubs.opengroup.org/onlinepubs/9699919799/utilities/find.html
+
+
+Performance
+-----------
+
+By avoiding syscalls, `walk` achieves substantially better performance than
+`find`. A microbenchmark –
+
+ $ time find /usr >/dev/null
+
+ real 0m3.542s
+ user 0m0.880s
+ sys 0m2.646s
+ $ time walk /usr >/dev/null
+
+ real 0m2.311s
+ user 0m0.370s
+ sys 0m1.926s
+
+– shows `walk` executing nearly 40% faster on a local file system with a hot
+cache. Performance on network file systems should be even better. On the other
+hand, `find` implements its predicates in-process, making them orders of
+magnitude faster than `sor`:
+
+ $ time find /usr -type f >/dev/null
+
+ real 0m3.464s
+ user 0m0.831s
+ sys 0m2.615s
+ $ time walk /usr | sor 'test -f' >/dev/null
+
+ real 7m40.127s
+ user 1m47.818s
+ sys 2m48.595s
+
+
+History
+-------
+
+`walk` and `sor` were originally written for [Plan 9 from Bell Labs][] by
+[Dan Cross][]. The [original source][] is available.
+
+[Dan Cross]: http://pub.gajendra.net/about
+[Plan 9 from Bell Labs]: https://web.archive.org/web/20170601064029/http://plan9.bell-labs.com/plan9/index.html
+[original source]: https://web.archive.org/web/http://plan9.bell-labs.com/sources/contrib/cross/
+
+
+Disclaimer
+----------
+
+This is not an official Google product.
diff --git a/sor b/sor
new file mode 100755
index 0000000..12f5652
--- /dev/null
+++ b/sor
@@ -0,0 +1,23 @@
+#!/bin/bash
+# Copyright 2019 Google LLC
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+# https://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+while read file; do
+ for test in "$@"; do
+ if eval "$test \"$file\""; then
+ echo "$file"
+ continue 2
+ fi
+ done
+done
diff --git a/sor.1 b/sor.1
new file mode 100644
index 0000000..ab69baf
--- /dev/null
+++ b/sor.1
@@ -0,0 +1,31 @@
+.\" Copyright 2019 Google LLC
+.\"
+.\" Licensed under the Apache License, Version 2.0 (the "License");
+.\" you may not use this file except in compliance with the License.
+.\" You may obtain a copy of the License at
+.\"
+.\" https://www.apache.org/licenses/LICENSE-2.0
+.\"
+.\" Unless required by applicable law or agreed to in writing, software
+.\" distributed under the License is distributed on an "AS IS" BASIS,
+.\" WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+.\" See the License for the specific language governing permissions and
+.\" limitations under the License.
+.TH SOR 1 2019-09-16
+.SH NAME
+sor \- combine shell predicates with logical or
+.SH SYNOPSIS
+.B sor
+.IR SNIPPET ...
+.SH DESCRIPTION
+Read paths from standard input. For each path, evaluate each argument as a
+.BR bash (1)
+snippet with the path as the first argument. Print the path to standard output
+if any of the snippets exits with status 0.
+.SH EXAMPLE
+.EX
+walk /etc | sor 'test -f'
+.EE
+.SH "SEE ALSO"
+.BR find (1),
+.BR walk (1)
diff --git a/walk.1 b/walk.1
new file mode 100644
index 0000000..7fcb3d6
--- /dev/null
+++ b/walk.1
@@ -0,0 +1,30 @@
+.\" Copyright 2019 Google LLC
+.\"
+.\" Licensed under the Apache License, Version 2.0 (the "License");
+.\" you may not use this file except in compliance with the License.
+.\" You may obtain a copy of the License at
+.\"
+.\" https://www.apache.org/licenses/LICENSE-2.0
+.\"
+.\" Unless required by applicable law or agreed to in writing, software
+.\" distributed under the License is distributed on an "AS IS" BASIS,
+.\" WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+.\" See the License for the specific language governing permissions and
+.\" limitations under the License.
+.TH WALK 1 2019-09-16
+.SH NAME
+walk \- walk file system
+.SH SYNOPSIS
+.B walk
+.RI [\| DIRECTORY ...\]
+.SH DESCRIPTION
+Recursively list the specified
+.I DIRECTORY
+(or directories). Recursively list the current directory if no directory is
+specified.
+.SH NOTES
+.B walk
+does not traverse symlinks.
+.SH "SEE ALSO"
+.BR find (1),
+.BR sor (1)
diff --git a/walk.c b/walk.c
new file mode 100644
index 0000000..6cce89a
--- /dev/null
+++ b/walk.c
@@ -0,0 +1,99 @@
+// Copyright 2019 Google LLC
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// https://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#include <errno.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+#include <dirent.h>
+
+static const char *const JUST_CURRENT_DIRECTORY[] = {".", NULL};
+
+// Like readdir(3), but resets errno(3) before the call to make it easy to
+// check.
+static struct dirent *readdir2(DIR *const dirp)
+{
+ errno = 0;
+ return readdir(dirp);
+}
+
+// Like realloc(3), but exits the binary in an out-of-memory situation.
+static void *realloc2(void *ptr, const size_t size)
+{
+ if (!(ptr = realloc(ptr, size))) {
+ perror("realloc");
+ exit(EXIT_FAILURE);
+ }
+ return ptr;
+}
+
+static void strcpy3(char *dest, const char *s1, const char *s2, const char *s3)
+{
+ stpcpy(stpcpy(stpcpy(dest, s1), s2), s3);
+}
+
+// Walks the directory named dirname, printing the names of all files it
+// contains (but not the name of the directory itself). Returns 2 if dirname is
+// not a directory and 1 if another error occurs.
+static int walk(const char dirname[])
+{
+ DIR *const dir = opendir(dirname);
+ if (!dir) {
+ if (errno != ENOTDIR) {
+ perror(dirname);
+ return 1;
+ }
+ return 2;
+ }
+ int r = 0;
+ char *filename = NULL;
+ for (const struct dirent *f = readdir2(dir); f; f = readdir2(dir)) {
+ if (strcmp(f->d_name, ".") == 0
+ || strcmp(f->d_name, "..") == 0)
+ continue;
+ filename = realloc2(filename,
+ strlen(dirname) + 1 + strlen(f->d_name) + 1);
+ strcpy3(filename, dirname, "/", f->d_name);
+ // TODO(bbaren): Emulate Plan 9's cleanname(3).
+ puts(filename);
+ // Walk the file if we can successfully open it as a directory.
+ // Don't worry about it if it's not one (walk(filename) == 2).
+ if ((f->d_type == DT_DIR || f->d_type == DT_UNKNOWN)
+ && walk(filename) == 1)
+ r = 1;
+ }
+ if (errno) { // from readdir
+ perror(dirname);
+ r = 1;
+ }
+ free(filename);
+ if (closedir(dir)) {
+ perror(dirname);
+ r = 1;
+ }
+ return r;
+}
+
+int main(const int argc, const char *const argv[])
+{
+ int r = 0;
+ const char *const *const dirs =
+ argc == 1 ? JUST_CURRENT_DIRECTORY : argv + 1;
+ for (int i = 0; dirs[i]; ++i) {
+ puts(dirs[i]);
+ r |= walk(dirs[i]);
+ }
+ return r;
+}