Package: moreutils
Version: 0.11
Tags: patch
Attached is a patch against moreutils to add a -p/--preserve option to
sponge that prevents it from modifying the output if the input is
identical. This means that something like this:
generate-web-page | sponge -p > ~/public_html/index.html
no longer results in the output file looking modified to web browsers.
To implement this, I am afraid I felt it necessary to change a bunch of
other things, too. The code no longer keeps the entire input file in
memory, instead it uses a temporary file. I also added option parsing
with getopt_long.
--
Fundamental truth #4: Typing URLs always introduces errors. Always copy
+paste.
=== added file 'check-sponge'
--- /dev/null
+++ check-sponge
@@ -0,0 +1,36 @@
+#!/bin/sh
+#
+# Check that ./sponge behaves correctly.
+
+set -e
+
+die()
+{
+ echo "$@" 1>&2
+ exit 1
+}
+
+input=$(mktemp)
+output=$(mktemp)
+
+echo This is a sponge test data file. > "$input"
+
+./sponge < "$input" "$output"
+cmp "$input" "$output" || die "sponge created the wrong output"
+
+TZ=GMT touch -t 197001010000 "$output"
+./sponge -p < "$input" "$output"
+mtime=$(TZ=GMT stat -c %Y "$output")
+[ "$mtime" == 0 ] || die "sponge modified the timestamp"
+
+TZ=GMT touch -t 197001010000 "$output"
+echo different input | ./sponge -p "$output"
+mtime=$(TZ=GMT stat -c %Y "$output")
+[ "$mtime" != 0 ] || die "sponge modified the timestamp"
+
+TZ=GMT touch -t 197001010000 "$output"
+./sponge < "$input" "$output"
+mtime=$(TZ=GMT stat -c %Y "$output")
+[ "$mtime" != 0 ] || die "sponge didn't modify the timestamp"
+
+rm -f "$input" "$output"
=== modified file 'Makefile'
--- Makefile
+++ Makefile
@@ -16,8 +16,9 @@
mkdir -p $(PREFIX)/usr/share/man/man1
install $(MANS) $(PREFIX)/usr/share/man/man1
-check: isutf8
+check: isutf8 sponge
./check-isutf8
+ ./check-sponge
isutf8.1: isutf8.docbook
docbook2x-man $<
=== modified file 'sponge.c'
--- sponge.c
+++ sponge.c
@@ -1,24 +1,24 @@
/*
- * sponge.c - read in all available info from stdin, then output it to
- * file named on the command line
- *
- * Copyright © 2006 Tollef Fog Heen
- *
- * This program is free software; you can redistribute it and/or
- * modify it under the terms of the GNU General Public License
- * version 2 as published by the Free Software Foundation.
- *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
- * General Public License for more details.
+ * sponge.c - read in all available info from stdin, then output it to
+ * file named on the command line
+ *
+ * Copyright © 2006 Tollef Fog Heen, Lars Wirzenius
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * version 2 as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307
* USA
- *
*/
+
#include <stdio.h>
#include <stdlib.h>
@@ -29,62 +29,176 @@
#include <errno.h>
#include <string.h>
-void usage() {
- printf("sponge <file>: suck in all input from stdin and write it to <file>");
- exit(0);
-}
+#define _GNU_SOURCE
+#include <getopt.h>
+
+
+static struct option options[] = {
+ { "help", no_argument, NULL, 'h' },
+ { "preserve", no_argument, NULL, 'p' },
+};
+
+
+static void usage() {
+ printf("\
+Usage: sponge [-hp] [--help] [--preserve] file\n\
+where\n\
+ -h, --help Print out this help.\n\
+ -p, --preserve Preserve output file if contents match.\n\
+");
+ exit(0);
+}
+
+
+static char *xmalloc(size_t n)
+{
+ void *p;
+
+ p = malloc(n);
+ if (p == NULL) {
+ perror("malloc");
+ exit(1);
+ }
+ return p;
+}
+
+
+static int make_temp(const char *final_name, char **temp, int *fd)
+{
+ static const char suffix[] = "XXXXXX";
+ size_t size;
+ char *template;
+
+ size = strlen(final_name) + sizeof(suffix);
+ template = xmalloc(size);
+ snprintf(template, size, "%s%s", final_name, suffix);
+
+ *fd = mkstemp(template);
+ if (*fd == -1) {
+ perror("mkstemp");
+ free(template);
+ return -1;
+ } else {
+ *temp = template;
+ return 0;
+ }
+}
+
+
+static int same_contents(int fd1, const char *filename)
+{
+ int fd2;
+ char buf1[8192];
+ char buf2[sizeof(buf1)];
+ ssize_t n1, n2;
+ int ret;
+ struct stat st1, st2;
+
+ if (stat(filename, &st2) != -1) {
+ if (fstat(fd1, &st1) == -1) {
+ perror("fstat");
+ exit(1);
+ }
+ if (st1.st_size != st2.st_size)
+ return 0;
+ }
+
+ if (lseek(fd1, 0, 0) == -1) {
+ perror("lseek");
+ exit(1);
+ }
+
+ fd2 = open(filename, O_RDONLY, 0);
+ if (fd2 == -1)
+ return 0;
+
+ ret = 1;
+
+ do {
+ n1 = read(fd1, buf1, sizeof(buf1));
+ if (n1 == -1) {
+ perror("read");
+ exit(1);
+ }
+
+ n2 = read(fd2, buf2, sizeof(buf2));
+ if (n2 == -1) {
+ perror("read");
+ exit(1);
+ }
+
+ if (n1 != n2 || memcmp(buf1, buf2, n1) != 0) {
+ ret = 0;
+ break;
+ }
+ } while (n1 != 0);
+
+ close(fd2);
+ return ret;
+}
+
int main(int argc, char **argv) {
- char *buf, *bufstart;
- size_t bufsize = 8192;
- size_t bufused = 0;
- ssize_t i = 0;
- int outfd;
-
- if (argc != 2) {
- usage();
- }
-
- bufstart = buf = malloc(bufsize);
- if (!buf) {
- perror("malloc");
- exit(1);
- }
-
- while ((i = read(0, buf, bufsize - bufused)) > 0) {
- bufused = bufused+i;
- if (bufused == bufsize) {
- bufsize *= 2;
- bufstart = realloc(bufstart, bufsize);
- if (!bufstart) {
- perror("realloc");
- exit(1);
- }
- }
- buf = bufstart + bufused;
- }
- if (i == -1) {
- perror("read");
- exit(1);
- }
-
- outfd = open(argv[1], O_CREAT | O_TRUNC | O_WRONLY, 0666);
- if (outfd == -1) {
- fprintf(stderr, "Can't open %s: %s\n", argv[1], strerror(errno));
- exit(1);
- }
-
- i = write(outfd, bufstart, bufused);
- if (i == -1) {
- perror("write");
- exit(1);
- }
-
- i = close(outfd);
- if (i == -1) {
- perror("close");
- exit(1);
- }
-
- return 0;
-}
+ char buf[8192];
+ ssize_t i = 0;
+ int opt;
+ int long_index;
+ int preserve;
+ char *output;
+ char *temp;
+ int tempfd;
+
+ preserve = 0;
+
+ for (;;) {
+ opt = getopt_long(argc, argv, "hp", options, &long_index);
+ if (opt == -1)
+ break;
+
+ switch (opt) {
+ case 'p':
+ preserve = 1;
+ break;
+
+ case 'h':
+ default:
+ usage();
+ break;
+ }
+ }
+
+ if (optind + 1 != argc) {
+ fprintf(stderr, "Missing filename argument.\n");
+ exit(1);
+ }
+
+ output = argv[optind];
+
+ if (make_temp(output, &temp, &tempfd) == -1)
+ exit(1);
+
+ while ((i = read(0, buf, sizeof(buf))) > 0) {
+ if (write(tempfd, buf, i) != i) {
+ perror("write");
+ exit(1);
+ }
+ }
+ if (i == -1) {
+ perror("read");
+ exit(1);
+ }
+
+ if (preserve && same_contents(tempfd, output)) {
+ remove(temp);
+ return 0;
+ }
+
+ if (rename(temp, output) == -1) {
+ perror("rename");
+ exit(1);
+ }
+
+ close(tempfd);
+
+ return 0;
+}
=== modified file 'sponge.docbook'
--- sponge.docbook
+++ sponge.docbook
@@ -31,7 +31,7 @@
<firstname>Joey</firstname>
<surname>Hess</surname>
</author>
- <date>2006-02-19</date>
+ <date>2006-06-14</date>
</refentryinfo>
<refmeta>
@@ -61,4 +61,30 @@
the same file. </para>
</refsect1>
+
+ <refsect1>
+ <title>OPTIONS</title>
+
+ <variablelist>
+
+ <varlistentry>
+ <term><option>-h</option></term>
+ <term><option>--help</option></term>
+ <listitem>
+ <para>Print out a help summary.</para>
+ </listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term><option>-p</option></term>
+ <term><option>--preserve</option></term>
+ <listitem>
+ <para>Don't overwrite the output if the input is
+ identical.</para>
+ </listitem>
+ </varlistentry>
+
+ </variablelist>
+
+ </refsect1>
</refentry>
