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author | Yann Collet <cyan@fb.com> | 2019-04-20 00:08:40 (GMT) |
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committer | Yann Collet <cyan@fb.com> | 2019-04-20 00:08:40 (GMT) |
commit | 5f8ac02b7707c03f93ff10ac1362d2c618bd3c42 (patch) | |
tree | 2b007309534f4a65111bd12711ae29e99b584832 /programs | |
parent | 7a4e3b1fac5cd9d4ec7c8d0091329ba107ec2131 (diff) | |
download | lz4-5f8ac02b7707c03f93ff10ac1362d2c618bd3c42.zip lz4-5f8ac02b7707c03f93ff10ac1362d2c618bd3c42.tar.gz lz4-5f8ac02b7707c03f93ff10ac1362d2c618bd3c42.tar.bz2 |
cli: display a warning whenever default output is stdout while input != stdin
This behavior has been preserved for compatibility with existing ecosystem.
But it's problematic, as some environment start `lz4` without identifying stdout as console by default,
leading to a change of behavior for a same line of script.
A more sensible policy would be to default to stdout only when input is stdin.
Soft change for the time being : keep the behavior, just print a warning message.
User should prefer `-c` to explicitly select `stdout`.
Also : updated tests in Makefile to explicitly select `stdout` with `-c`.
Diffstat (limited to 'programs')
-rw-r--r-- | programs/lz4cli.c | 36 |
1 files changed, 25 insertions, 11 deletions
diff --git a/programs/lz4cli.c b/programs/lz4cli.c index 8bd7042..279aaf1 100644 --- a/programs/lz4cli.c +++ b/programs/lz4cli.c @@ -652,7 +652,15 @@ int main(int argc, const char** argv) /* No output filename ==> try to select one automatically (when possible) */ while ((!output_filename) && (multiple_inputs==0)) { - if (!IS_CONSOLE(stdout)) { output_filename=stdoutmark; break; } /* Default to stdout whenever possible (i.e. not a console) */ + + if (!IS_CONSOLE(stdout)) { + /* Default to stdout whenever stdout is not the console. + * Note : this policy is likely to change in the future, don't rely on it ! + * prefer using an explicit `-c` flag */ + DISPLAYLEVEL(1, "Warning : using stdout as default output. Do not rely on this behavior: use explicit `-c` instead ! \n"); + output_filename=stdoutmark; + break; + } if (mode == om_auto) { /* auto-determine compression or decompression, based on file extension */ mode = determineOpMode(input_filename); } @@ -682,10 +690,14 @@ int main(int argc, const char** argv) break; } - /* Check if output is defined as console; trigger an error in this case */ + if (multiple_inputs==0) assert(output_filename); + /* when multiple_inputs==1, output_filename may simply be useless, + * however, output_filename must be !NULL for next strcmp() tests */ if (!output_filename) output_filename = "*\\dummy^!//"; + + /* Check if output is defined as console; trigger an error in this case */ if (!strcmp(output_filename,stdoutmark) && IS_CONSOLE(stdout) && !forceStdout) { - DISPLAYLEVEL(1, "refusing to write to console without -c\n"); + DISPLAYLEVEL(1, "refusing to write to console without -c \n"); exit(1); } /* Downgrade notification level in stdout and multiple file mode */ @@ -701,21 +713,23 @@ int main(int argc, const char** argv) LZ4IO_setNotificationLevel((int)displayLevel); if (ifnIdx == 0) multiple_inputs = 0; if (mode == om_decompress) { - if (multiple_inputs) - operationResult = LZ4IO_decompressMultipleFilenames(prefs, inFileNames, ifnIdx, !strcmp(output_filename,stdoutmark) ? stdoutmark : LZ4_EXTENSION); - else + if (multiple_inputs) { + assert(ifnIdx <= INT_MAX); + operationResult = LZ4IO_decompressMultipleFilenames(prefs, inFileNames, (int)ifnIdx, !strcmp(output_filename,stdoutmark) ? stdoutmark : LZ4_EXTENSION); + } else { operationResult = DEFAULT_DECOMPRESSOR(prefs, input_filename, output_filename); + } } else { /* compression is default action */ if (legacy_format) { DISPLAYLEVEL(3, "! Generating LZ4 Legacy format (deprecated) ! \n"); LZ4IO_compressFilename_Legacy(prefs, input_filename, output_filename, cLevel); } else { - if (multiple_inputs) - operationResult = LZ4IO_compressMultipleFilenames(prefs, inFileNames, ifnIdx, !strcmp(output_filename,stdoutmark) ? stdoutmark : LZ4_EXTENSION, cLevel); - else + if (multiple_inputs) { + assert(ifnIdx <= INT_MAX); + operationResult = LZ4IO_compressMultipleFilenames(prefs, inFileNames, (int)ifnIdx, !strcmp(output_filename,stdoutmark) ? stdoutmark : LZ4_EXTENSION, cLevel); + } else { operationResult = DEFAULT_COMPRESSOR(prefs, input_filename, output_filename, cLevel); - } - } + } } } _cleanup: if (main_pause) waitEnter(); |