summaryrefslogtreecommitdiffstats
path: root/zdiff.cc
diff options
context:
space:
mode:
Diffstat (limited to 'zdiff.cc')
-rw-r--r--zdiff.cc476
1 files changed, 476 insertions, 0 deletions
diff --git a/zdiff.cc b/zdiff.cc
new file mode 100644
index 0000000..d01f492
--- /dev/null
+++ b/zdiff.cc
@@ -0,0 +1,476 @@
+/* Zdiff - decompress and compare two files line by line
+ Copyright (C) 2010 Antonio Diaz Diaz.
+
+ This program is free software: you can redistribute it and/or modify
+ it under the terms of the GNU General Public License as published by
+ the Free Software Foundation, either version 3 of the License, or
+ (at your option) any later version.
+
+ 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, see <http://www.gnu.org/licenses/>.
+*/
+
+#define _FILE_OFFSET_BITS 64
+
+#include <cctype>
+#include <cerrno>
+#include <climits>
+#include <csignal>
+#include <cstdio>
+#include <cstdlib>
+#include <cstring>
+#include <string>
+#include <vector>
+#include <fcntl.h>
+#include <stdint.h>
+#include <unistd.h>
+#include <sys/stat.h>
+#if defined(__MSVCRT__) || defined(__OS2__)
+#include <io.h>
+#endif
+
+#include "arg_parser.h"
+#include "zutils.h"
+
+#if CHAR_BIT != 8
+#error "Environments where CHAR_BIT != 8 are not supported."
+#endif
+
+#ifndef LLONG_MAX
+#define LLONG_MAX 0x7FFFFFFFFFFFFFFFLL
+#endif
+#ifndef LLONG_MIN
+#define LLONG_MIN (-LLONG_MAX - 1LL)
+#endif
+#ifndef ULLONG_MAX
+#define ULLONG_MAX 0xFFFFFFFFFFFFFFFFULL
+#endif
+
+
+namespace {
+
+std::string fifonames[2]; // names of the two fifos passed to diff
+
+#ifdef O_BINARY
+const int o_binary = O_BINARY;
+#else
+const int o_binary = 0;
+#endif
+
+struct { const char * from; const char * to; } const known_extensions[] = {
+ { ".bz2", "" },
+ { ".tbz", ".tar" },
+ { ".tbz2", ".tar" },
+ { ".gz", "" },
+ { ".tgz", ".tar" },
+ { ".lz", "" },
+ { ".tlz", ".tar" },
+ { ".xz", "" },
+ { ".txz", ".tar" },
+ { 0, 0 } };
+
+
+void show_help() throw()
+ {
+ std::printf( "Zdiff compares two files (\"-\" means standard input), and if they\n" );
+ std::printf( "differ, shows the differences line by line. If any given file is\n" );
+ std::printf( "compressed, its uncompressed content is used. Zdiff is a front end to\n" );
+ std::printf( "the diff program and has the limitation that messages from diff refer to\n" );
+ std::printf( "temporary filenames instead of those specified.\n" );
+ std::printf( "The supported compressors are bzip2, gzip, lzip and xz.\n" );
+ std::printf( "\nUsage: zdiff [options] file1 [file2]\n" );
+ std::printf( "\nCompares <file1> to <file2>. If <file2> is omitted zdiff tries the\n" );
+ std::printf( "following:\n" );
+ std::printf( "If <file1> is compressed, compares <file1> to the file with the\n" );
+ std::printf( "corresponding decompressed file name (removes the extension from\n" );
+ std::printf( "<file1>).\n" );
+ std::printf( "If <file1> is not compressed, compares <file1> to the uncompressed\n" );
+ std::printf( "contents of <file1>.[bz2|gz|lz|xz] (the first one that is found).\n" );
+ std::printf( "If no suitable file is found, compares <file1> to data read from\n" );
+ std::printf( "standard input.\n" );
+ std::printf( "\nExit status is 0 if inputs are identical, 1 if different, 2 if trouble.\n" );
+ std::printf( "\nOptions:\n" );
+ std::printf( " -h, --help display this help and exit\n" );
+ std::printf( " -V, --version output version information and exit\n" );
+ std::printf( " -a, --text treat all files as text\n" );
+ std::printf( " -b, --ignore-space-change ignore changes in the amount of white space\n" );
+ std::printf( " -B, --ignore-blank-lines ignore changes whose lines are all blank\n" );
+ std::printf( " -c use the context output format\n" );
+ std::printf( " -C, --context=<n> same as -c but use <n> lines of context\n" );
+ std::printf( " -d, --minimal try hard to find a smaller set of changes\n" );
+ std::printf( " -E, --ignore-tab-expansion ignore changes due to tab expansion\n" );
+ std::printf( " -i, --ignore-case ignore case differences in file contents\n" );
+ std::printf( " -p, --show-c-function show which C function each change is in\n" );
+ std::printf( " -q, --brief output only whether files differ\n" );
+ std::printf( " -s, --report-identical-files report when two files are identical\n" );
+ std::printf( " -t, --expand-tabs expand tabs to spaces in output\n" );
+ std::printf( " -T, --initial-tab make tabs line up by prepending a tab\n" );
+ std::printf( " -u use the unified output format\n" );
+ std::printf( " -U, --unified=<n> same as -u but use <n> lines of context\n" );
+ std::printf( " -w, --ignore-all-space ignore all white space\n" );
+ std::printf( "Numbers may be followed by a multiplier: k = kB = 10^3 = 1000,\n" );
+ std::printf( "Ki = KiB = 2^10 = 1024, M = 10^6, Mi = 2^20, G = 10^9, Gi = 2^30, etc...\n" );
+ show_help_addr();
+ }
+
+
+int open_instream( const std::string & input_filename ) throw()
+ {
+ int infd = open( input_filename.c_str(), O_RDONLY | o_binary );
+ if( infd < 0 && verbosity >= 0 )
+ std::fprintf( stderr, "%s: Can't open input file `%s': %s.\n",
+ util_name, input_filename.c_str(), std::strerror( errno ) );
+ return infd;
+ }
+
+
+int open_other_instream( std::string & name ) throw()
+ {
+ for( int i = 0; known_extensions[i].from; ++i )
+ { // search uncompressed version
+ const std::string from( known_extensions[i].from );
+ if( name.size() > from.size() &&
+ name.compare( name.size() - from.size(), from.size(), from ) == 0 )
+ {
+ name.resize( name.size() - from.size() );
+ name += known_extensions[i].to;
+ return open( name.c_str(), O_RDONLY | o_binary );
+ }
+ }
+ for( int i = 0; simple_extensions[i]; ++i )
+ { // search compressed version
+ const std::string s( name + simple_extensions[i] );
+ const int infd = open( s.c_str(), O_RDONLY | o_binary );
+ if( infd >= 0 ) { name = s; return infd; }
+ }
+ return -1;
+ }
+
+
+bool check_identical( const char * const name1, const char * const name2 ) throw()
+ {
+ if( !std::strcmp( name1, name2 ) ) return true;
+ struct stat stat1, stat2;
+ if( stat( name1, &stat1 ) || stat( name2, &stat2 ) ) return false;
+ return ( stat1.st_ino == stat2.st_ino && stat1.st_dev == stat2.st_dev );
+ }
+
+
+const char * my_basename( const char * filename ) throw()
+ {
+ const char * c = filename;
+ while( *c ) { if( *c == '/' ) { filename = c + 1; } ++c; }
+ return filename;
+ }
+
+
+void remove_fifos() throw()
+ {
+ if( fifonames[0].size() )
+ { std::remove( fifonames[0].c_str() ); fifonames[0].clear(); }
+ if( fifonames[1].size() )
+ { std::remove( fifonames[1].c_str() ); fifonames[1].clear(); }
+ }
+
+
+// Set fifonames[i] to "${TMPDIR}/<coded_pid><i>_<basename(filenames[i])>"
+// and create FIFOs.
+bool set_fifonames( const std::string filenames[2] )
+ {
+ enum { num_codes = 36 };
+ const char * const codes = "0123456789abcdefghijklmnopqrstuvwxyz";
+ const char * p = std::getenv( "TMPDIR" );
+ const int pid = getpid();
+
+ for( int i = 0; i < 2; ++i )
+ {
+ if( p ) fifonames[i] = p; else fifonames[i] = "/tmp";
+ fifonames[i] += '/';
+ int n = ( 2 * pid ) + i;
+ const unsigned int pos = fifonames[i].size();
+ do { fifonames[i].insert( pos, 1, codes[n % num_codes] );
+ n /= num_codes; }
+ while( n );
+ fifonames[i] += '_';
+ fifonames[i] += my_basename( filenames[i].c_str() );
+ }
+
+ for( int i = 0; i < 2; ++i )
+ if( mkfifo( fifonames[i].c_str(), S_IRUSR | S_IWUSR ) != 0 )
+ {
+ if( errno == EEXIST )
+ {
+ std::remove( fifonames[i].c_str() );
+ if( mkfifo( fifonames[i].c_str(), S_IRUSR | S_IWUSR ) == 0 )
+ continue;
+ }
+ if( verbosity >= 0 )
+ std::fprintf( stderr, "%s: Can't create FIFO `%s': %s.\n",
+ util_name, fifonames[i].c_str(), std::strerror( errno ) );
+ return false;
+ }
+ return true;
+ }
+
+
+bool set_data_feeder( const std::string & fifoname, const int infd,
+ pid_t * const pidp )
+ {
+ std::string file_type;
+ const uint8_t * magic_data;
+ int magic_size;
+ const bool compressed =
+ test_format( infd, file_type, &magic_data, &magic_size );
+
+ if( compressed ) // compressed with `file_type'
+ {
+ int fda[2]; // pipe from feeder to decompressor
+ if( pipe( fda ) < 0 )
+ { show_error( "Can't create pipe", errno ); return false; }
+ const pid_t pid = fork();
+ if( pid == 0 ) // child (decompressor feeder)
+ {
+ const pid_t pid2 = fork();
+ if( pid2 == 0 ) // grandchild (decompressor)
+ {
+ const int outfd = open( fifoname.c_str(), O_WRONLY | o_binary );
+ if( outfd < 0 )
+ {
+ if( verbosity >= 0 )
+ std::fprintf( stderr, "%s: Can't open FIFO `%s' for writing: %s.\n",
+ util_name, fifoname.c_str(), std::strerror( errno ) );
+ _exit( 2 );
+ }
+ if( dup2( fda[0], STDIN_FILENO ) >= 0 &&
+ dup2( outfd, STDOUT_FILENO ) >= 0 &&
+ close( fda[0] ) == 0 && close( fda[1] ) == 0 &&
+ close( outfd ) == 0 )
+ execlp( file_type.c_str(), file_type.c_str(), "-cdfq", (char *)0 );
+ if( verbosity >= 0 )
+ std::fprintf( stderr, "%s: Can't exec `%s': %s.\n",
+ util_name, file_type.c_str(), std::strerror( errno ) );
+ _exit( 2 );
+ }
+ if( pid2 < 0 )
+ {
+ if( verbosity >= 0 )
+ std::fprintf( stderr, "%s: Can't fork `%s': %s.\n",
+ util_name, file_type.c_str(), std::strerror( errno ) );
+ _exit( 2 );
+ }
+
+ if( close( fda[0] ) != 0 ||
+ !feed_data( infd, fda[1], magic_data, magic_size ) )
+ _exit( 2 );
+ if( close( fda[1] ) != 0 )
+ { show_error( "Can't close output of feeder", errno ); _exit( 2 ); }
+ _exit( wait_for_child( pid2, file_type.c_str() ) );
+ }
+ // parent
+ close( fda[0] ); close( fda[1] );
+ if( pid < 0 )
+ { show_error( "Can't fork decompressor feeder", errno ); return false; }
+ *pidp = pid;
+ }
+ else // not compressed
+ {
+ const pid_t pid = fork();
+ if( pid == 0 ) // child (feeder)
+ {
+ const int outfd = open( fifoname.c_str(), O_WRONLY | o_binary );
+ if( outfd < 0 )
+ {
+ if( verbosity >= 0 )
+ std::fprintf( stderr, "%s: Can't open FIFO `%s' for writing: %s.\n",
+ util_name, fifoname.c_str(), std::strerror( errno ) );
+ _exit( 2 );
+ }
+ if( !feed_data( infd, outfd, magic_data, magic_size ) )
+ _exit( 2 );
+ if( close( outfd ) != 0 )
+ { show_error( "Can't close output of feeder", errno ); _exit( 2 ); }
+ _exit( 0 );
+ }
+ // parent
+ if( pid < 0 )
+ { show_error( "Can't fork data feeder", errno ); return false; }
+ *pidp = pid;
+ }
+ return true;
+ }
+
+
+extern "C" void signal_handler( int sig ) throw()
+ {
+ remove_fifos();
+ std::signal( sig, SIG_DFL );
+ std::raise( sig );
+ }
+
+
+void set_signals() throw()
+ {
+ std::signal( SIGHUP, signal_handler );
+ std::signal( SIGINT, signal_handler );
+ std::signal( SIGTERM, signal_handler );
+ }
+
+} // end namespace
+
+
+int main( const int argc, const char * const argv[] )
+ {
+ std::vector< const char * > diff_args; // args to diff, maybe empty
+ invocation_name = argv[0];
+ util_name = "zdiff";
+
+ const Arg_parser::Option options[] =
+ {
+ { 'a', "text", Arg_parser::no },
+ { 'b', "ignore-space-change", Arg_parser::no },
+ { 'B', "ignore-blank-lines", Arg_parser::no },
+ { 'c', 0, Arg_parser::no },
+ { 'C', "context", Arg_parser::yes },
+ { 'd', "minimal", Arg_parser::no },
+ { 'E', "ignore-tab-expansion", Arg_parser::no },
+ { 'h', "help", Arg_parser::no },
+ { 'i', "ignore-case", Arg_parser::no },
+ { 'p', "show-c-function", Arg_parser::no },
+ { 'q', "brief", Arg_parser::no },
+ { 's', "report-identical-files", Arg_parser::no },
+ { 't', "expand-tabs", Arg_parser::no },
+ { 'T', "initial-tab", Arg_parser::no },
+ { 'u', 0, Arg_parser::no },
+ { 'U', "unified", Arg_parser::yes },
+ { 'V', "version", Arg_parser::no },
+ { 'w', "ignore-all-space", Arg_parser::no },
+ { 0 , 0, Arg_parser::no } };
+
+ const Arg_parser parser( argc, argv, options );
+ if( parser.error().size() ) // bad option
+ { show_error( parser.error().c_str(), 0, true ); return 2; }
+
+ int argind = 0;
+ for( ; argind < parser.arguments(); ++argind )
+ {
+ const int code = parser.code( argind );
+ if( !code ) break; // no more options
+ const char * const arg = parser.argument( argind ).c_str();
+ switch( code )
+ {
+ case 'a': diff_args.push_back( "-a" ); break;
+ case 'b': diff_args.push_back( "-b" ); break;
+ case 'B': diff_args.push_back( "-B" ); break;
+ case 'c': diff_args.push_back( "-c" ); break;
+ case 'C': diff_args.push_back( "-C" ); diff_args.push_back( arg ); break;
+ case 'd': diff_args.push_back( "-d" ); break;
+ case 'E': diff_args.push_back( "-E" ); break;
+ case 'h': show_help(); return 0;
+ case 'i': diff_args.push_back( "-i" ); break;
+ case 'p': diff_args.push_back( "-p" ); break;
+ case 'q': diff_args.push_back( "-q" ); break;
+ case 's': diff_args.push_back( "-s" ); break;
+ case 't': diff_args.push_back( "-t" ); break;
+ case 'T': diff_args.push_back( "-T" ); break;
+ case 'u': diff_args.push_back( "-u" ); break;
+ case 'U': diff_args.push_back( "-U" ); diff_args.push_back( arg ); break;
+ case 'V': show_version( "Zdiff" ); return 0;
+ case 'w': diff_args.push_back( "-w" ); break;
+ default : internal_error( "uncaught option" );
+ }
+ } // end process options
+
+#if defined(__MSVCRT__) || defined(__OS2__)
+ _setmode( STDIN_FILENO, O_BINARY );
+ _setmode( STDOUT_FILENO, O_BINARY );
+#endif
+
+ if( argind >= parser.arguments() )
+ { show_error( "No files given.", 0, true ); return 2; }
+ if( argind + 2 < parser.arguments() )
+ { show_error( "Too many files.", 0, true ); return 2; }
+
+ const int files = parser.arguments() - argind;
+ std::string filenames[2]; // file names of the two input files
+ filenames[0] = parser.argument( argind );
+ if( files == 2 ) filenames[1] = parser.argument( argind + 1 );
+
+ int infd[2]; // file descriptors of the two files
+ infd[0] = ( filenames[0] == "-" ) ?
+ STDIN_FILENO : open_instream( filenames[0] );
+ if( infd[0] < 0 ) return 2;
+
+ if( ( files == 1 && filenames[0] == "-" ) ||
+ ( files == 2 && check_identical( filenames[0].c_str(),
+ filenames[1].c_str() ) ) )
+ return 0;
+
+ if( files == 2 )
+ {
+ infd[1] = ( filenames[1] == "-" ) ?
+ STDIN_FILENO : open_instream( filenames[1] );
+ if( infd[1] < 0 ) return 2;
+ }
+ else
+ {
+ filenames[1] = filenames[0];
+ infd[1] = open_other_instream( filenames[1] );
+ if( infd[1] < 0 ) { infd[1] = STDIN_FILENO; filenames[1] = "-"; }
+ }
+
+ std::atexit( remove_fifos );
+ set_signals();
+ if( !set_fifonames( filenames ) ) return 2;
+
+ const pid_t diff_pid = fork();
+ if( diff_pid == 0 ) // child (diff)
+ {
+ const char ** const argv = new const char *[diff_args.size()+5];
+ argv[0] = "diff";
+ for( unsigned int i = 0; i < diff_args.size(); ++i )
+ argv[i+1] = diff_args[i];
+ argv[diff_args.size()+1] = "--";
+ argv[diff_args.size()+2] = fifonames[0].c_str();
+ argv[diff_args.size()+3] = fifonames[1].c_str();
+ argv[diff_args.size()+4] = 0;
+ execvp( argv[0], (char **)argv );
+ show_error( "Can't exec `diff'." );
+ _exit( 2 );
+ }
+ // parent
+ if( diff_pid < 0 )
+ { show_error( "Can't fork `diff'", errno ); return 2; }
+
+ pid_t pid[2];
+ if( !set_data_feeder( fifonames[0], infd[0], &pid[0] ) ||
+ !set_data_feeder( fifonames[1], infd[1], &pid[1] ) )
+ return 2;
+
+ int retval = wait_for_child( diff_pid, "diff" );
+
+ if( retval != 0 )
+ {
+ if( pid[0] ) kill( pid[0], SIGTERM );
+ if( pid[1] ) kill( pid[1], SIGTERM );
+ }
+ else
+ if( ( pid[0] && wait_for_child( pid[0], "data feeder" ) != 0 ) ||
+ ( pid[1] && wait_for_child( pid[1], "data feeder" ) != 0 ) )
+ retval = 2;
+
+ for( int i = 0; i < 2; ++i )
+ if( filenames[i] != "-" && close( infd[i] ) != 0 )
+ {
+ if( verbosity >= 0 )
+ std::fprintf( stderr, "%s: Can't close input file `%s': %s.\n",
+ util_name, filenames[i].c_str(), std::strerror( errno ) );
+ retval = 2;
+ }
+
+ return retval;
+ }
generated by cgit v1.2.3 (git 2.39.1) at 2024-11-01 16:46:33 +0000