148 строки
3.8 KiB
C
148 строки
3.8 KiB
C
/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
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/*
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* The contents of this file are subject to the Netscape Public License
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* Version 1.1 (the "NPL"); you may not use this file except in
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* compliance with the NPL. You may obtain a copy of the NPL at
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* http://www.mozilla.org/NPL/
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*
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* Software distributed under the NPL is distributed on an "AS IS" basis,
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* WITHOUT WARRANTY OF ANY KIND, either express or implied. See the NPL
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* for the specific language governing rights and limitations under the
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* NPL.
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*
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* The Initial Developer of this code under the NPL is Netscape
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* Communications Corporation. Portions created by Netscape are
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* Copyright (C) 1998 Netscape Communications Corporation. All Rights
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* Reserved.
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*/
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#include "prio.h"
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#include "prprf.h"
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#include "prinit.h"
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#include "prthread.h"
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#include "prinrval.h"
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#include "plerror.h"
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#include "plgetopt.h"
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#include <stdlib.h>
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#define BUFFER_SIZE 500
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static PRFileDesc *out = NULL, *err = NULL;
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static void Help(void)
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{
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PR_fprintf(err, "Usage: tail [-n <n>] [-f] [-h] <filename>\n");
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PR_fprintf(err, "\t-t <n> Dally time in milliseconds\n");
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PR_fprintf(err, "\t-n <n> Number of bytes before <eof>\n");
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PR_fprintf(err, "\t-f Follow the <eof>\n");
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PR_fprintf(err, "\t-h This message and nothing else\n");
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} /* Help */
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PRIntn main(PRIntn argc, char **argv)
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{
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PRIntn rv = 0;
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PLOptStatus os;
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PRStatus status;
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PRFileDesc *file;
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PRFileInfo fileInfo;
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PRIntervalTime dally;
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char buffer[BUFFER_SIZE];
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PRBool follow = PR_FALSE;
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const char *filename = NULL;
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PRUint32 position = 0, seek = 0, time = 0;
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PLOptState *opt = PL_CreateOptState(argc, argv, "hfn:");
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out = PR_GetSpecialFD(PR_StandardOutput);
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err = PR_GetSpecialFD(PR_StandardError);
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while (PL_OPT_EOL != (os = PL_GetNextOpt(opt)))
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{
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if (PL_OPT_BAD == os) continue;
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switch (opt->option)
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{
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case 0: /* it's the filename */
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filename = opt->value;
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break;
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case 'n': /* bytes before end of file */
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seek = atoi(opt->value);
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break;
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case 't': /* dally time */
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time = atoi(opt->value);
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break;
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case 'f': /* follow the end of file */
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follow = PR_TRUE;
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break;
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case 'h': /* user wants some guidance */
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Help(); /* so give him an earful */
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return 2; /* but not a lot else */
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break;
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default:
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break;
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}
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}
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PL_DestroyOptState(opt);
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if (0 == time) time = 1000;
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dally = PR_MillisecondsToInterval(time);
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if (NULL == filename)
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{
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(void)PR_fprintf(out, "Input file not specified\n");
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rv = 1; goto done;
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}
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file = PR_Open(filename, PR_RDONLY, 0);
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if (NULL == file)
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{
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PL_FPrintError(err, "File cannot be opened for reading");
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return 1;
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}
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status = PR_GetOpenFileInfo(file, &fileInfo);
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if (PR_FAILURE == status)
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{
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PL_FPrintError(err, "Cannot acquire status of file");
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rv = 1; goto done;
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}
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if (seek > 0)
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{
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if (seek > fileInfo.size) seek = 0;
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position = PR_Seek(file, (fileInfo.size - seek), PR_SEEK_SET);
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if (-1 == (PRInt32)position)
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PL_FPrintError(err, "Cannot seek to starting position");
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}
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do
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{
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while (position < fileInfo.size)
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{
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PRInt32 read, bytes = fileInfo.size - position;
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if (bytes > sizeof(buffer)) bytes = sizeof(buffer);
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read = PR_Read(file, buffer, bytes);
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if (read != bytes)
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PL_FPrintError(err, "Cannot read to eof");
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position += read;
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PR_Write(out, buffer, read);
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}
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if (follow)
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{
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PR_Sleep(dally);
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status = PR_GetOpenFileInfo(file, &fileInfo);
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if (PR_FAILURE == status)
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{
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PL_FPrintError(err, "Cannot acquire status of file");
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rv = 1; goto done;
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}
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}
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} while (follow);
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done:
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PR_Close(file);
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return rv;
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} /* main */
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/* tail.c */
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