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source: vbox/trunk/src/libs/xpcom18a4/nsprpub/tools/tail.c@ 2426

Last change on this file since 2426 was 1, checked in by vboxsync, 55 years ago

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1/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
2/* ***** BEGIN LICENSE BLOCK *****
3 * Version: MPL 1.1/GPL 2.0/LGPL 2.1
4 *
5 * The contents of this file are subject to the Mozilla Public License Version
6 * 1.1 (the "License"); you may not use this file except in compliance with
7 * the License. You may obtain a copy of the License at
8 * http://www.mozilla.org/MPL/
9 *
10 * Software distributed under the License is distributed on an "AS IS" basis,
11 * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
12 * for the specific language governing rights and limitations under the
13 * License.
14 *
15 * The Original Code is the Netscape Portable Runtime (NSPR).
16 *
17 * The Initial Developer of the Original Code is
18 * Netscape Communications Corporation.
19 * Portions created by the Initial Developer are Copyright (C) 1998-2000
20 * the Initial Developer. All Rights Reserved.
21 *
22 * Contributor(s):
23 *
24 * Alternatively, the contents of this file may be used under the terms of
25 * either the GNU General Public License Version 2 or later (the "GPL"), or
26 * the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
27 * in which case the provisions of the GPL or the LGPL are applicable instead
28 * of those above. If you wish to allow use of your version of this file only
29 * under the terms of either the GPL or the LGPL, and not to allow others to
30 * use your version of this file under the terms of the MPL, indicate your
31 * decision by deleting the provisions above and replace them with the notice
32 * and other provisions required by the GPL or the LGPL. If you do not delete
33 * the provisions above, a recipient may use your version of this file under
34 * the terms of any one of the MPL, the GPL or the LGPL.
35 *
36 * ***** END LICENSE BLOCK ***** */
37
38#include "prio.h"
39#include "prprf.h"
40#include "prinit.h"
41#include "prthread.h"
42#include "prinrval.h"
43
44#include "plerror.h"
45#include "plgetopt.h"
46
47#include <stdlib.h>
48
49#define BUFFER_SIZE 500
50
51static PRFileDesc *out = NULL, *err = NULL;
52
53static void Help(void)
54{
55 PR_fprintf(err, "Usage: tail [-n <n>] [-f] [-h] <filename>\n");
56 PR_fprintf(err, "\t-t <n> Dally time in milliseconds\n");
57 PR_fprintf(err, "\t-n <n> Number of bytes before <eof>\n");
58 PR_fprintf(err, "\t-f Follow the <eof>\n");
59 PR_fprintf(err, "\t-h This message and nothing else\n");
60} /* Help */
61
62PRIntn main(PRIntn argc, char **argv)
63{
64 PRIntn rv = 0;
65 PLOptStatus os;
66 PRStatus status;
67 PRFileDesc *file;
68 PRFileInfo fileInfo;
69 PRIntervalTime dally;
70 char buffer[BUFFER_SIZE];
71 PRBool follow = PR_FALSE;
72 const char *filename = NULL;
73 PRUint32 position = 0, seek = 0, time = 0;
74 PLOptState *opt = PL_CreateOptState(argc, argv, "hfn:");
75
76 out = PR_GetSpecialFD(PR_StandardOutput);
77 err = PR_GetSpecialFD(PR_StandardError);
78
79 while (PL_OPT_EOL != (os = PL_GetNextOpt(opt)))
80 {
81 if (PL_OPT_BAD == os) continue;
82 switch (opt->option)
83 {
84 case 0: /* it's the filename */
85 filename = opt->value;
86 break;
87 case 'n': /* bytes before end of file */
88 seek = atoi(opt->value);
89 break;
90 case 't': /* dally time */
91 time = atoi(opt->value);
92 break;
93 case 'f': /* follow the end of file */
94 follow = PR_TRUE;
95 break;
96 case 'h': /* user wants some guidance */
97 Help(); /* so give him an earful */
98 return 2; /* but not a lot else */
99 break;
100 default:
101 break;
102 }
103 }
104 PL_DestroyOptState(opt);
105
106 if (0 == time) time = 1000;
107 dally = PR_MillisecondsToInterval(time);
108
109 if (NULL == filename)
110 {
111 (void)PR_fprintf(out, "Input file not specified\n");
112 rv = 1; goto done;
113 }
114 file = PR_Open(filename, PR_RDONLY, 0);
115 if (NULL == file)
116 {
117 PL_FPrintError(err, "File cannot be opened for reading");
118 return 1;
119 }
120
121 status = PR_GetOpenFileInfo(file, &fileInfo);
122 if (PR_FAILURE == status)
123 {
124 PL_FPrintError(err, "Cannot acquire status of file");
125 rv = 1; goto done;
126 }
127 if (seek > 0)
128 {
129 if (seek > fileInfo.size) seek = 0;
130 position = PR_Seek(file, (fileInfo.size - seek), PR_SEEK_SET);
131 if (-1 == (PRInt32)position)
132 PL_FPrintError(err, "Cannot seek to starting position");
133 }
134
135 do
136 {
137 while (position < fileInfo.size)
138 {
139 PRInt32 read, bytes = fileInfo.size - position;
140 if (bytes > sizeof(buffer)) bytes = sizeof(buffer);
141 read = PR_Read(file, buffer, bytes);
142 if (read != bytes)
143 PL_FPrintError(err, "Cannot read to eof");
144 position += read;
145 PR_Write(out, buffer, read);
146 }
147
148 if (follow)
149 {
150 PR_Sleep(dally);
151 status = PR_GetOpenFileInfo(file, &fileInfo);
152 if (PR_FAILURE == status)
153 {
154 PL_FPrintError(err, "Cannot acquire status of file");
155 rv = 1; goto done;
156 }
157 }
158 } while (follow);
159
160done:
161 PR_Close(file);
162
163 return rv;
164} /* main */
165
166/* tail.c */
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