From 724285dadbdc88765c8fb83eab9816575a260966 Mon Sep 17 00:00:00 2001 From: Lasse Collin Date: Wed, 9 Nov 2022 14:10:52 +0200 Subject: [PATCH] xz: Add comments about stdin and src_st.st_size. "xz -v < regular_file > out.xz" doesn't display the percentage and estimated remaining time because it doesn't even try to check the input file size when input is read from stdin. This could be improved but for now there's just a comment to remind about it. --- src/xz/coder.c | 9 +++++++++ src/xz/file_io.c | 4 ++++ 2 files changed, 13 insertions(+) diff --git a/src/xz/coder.c b/src/xz/coder.c index d26ae6e9..5bca958f 100644 --- a/src/xz/coder.c +++ b/src/xz/coder.c @@ -1000,6 +1000,15 @@ coder_run(const char *filename) mytime_set_start_time(); // Initialize the progress indicator. + // + // NOTE: When reading from stdin, fstat() + // isn't called on it and thus src_st.st_size + // is zero. If stdin pointed to a regular + // file, it would still be possible to know + // the file size but then we would also need + // to take into account the current reading + // position since with stdin it isn't + // necessarily at the beginning of the file. const bool is_passthru = init_ret == CODER_INIT_PASSTHRU; const uint64_t in_size diff --git a/src/xz/file_io.c b/src/xz/file_io.c index 61857029..a5841b37 100644 --- a/src/xz/file_io.c +++ b/src/xz/file_io.c @@ -768,6 +768,10 @@ io_open_src(const char *src_name) // a statically allocated structure. static file_pair pair; + // This implicitly also initializes src_st.st_size to zero + // which is expected to be <= 0 by default. fstat() isn't + // called when reading from standard input but src_st.st_size + // is still read. pair = (file_pair){ .src_name = src_name, .dest_name = NULL,