fix updating of line-offsets output info in plain output mode reviewed by tom jones

sync diff_patience.c from got.git 336075a42a5ae0fa322db734c481d21998e82bb8

sync files from got.git 336075a42a5ae0fa322db734c481d21998e82bb8 ok tb@

fix build broken in previous commit 35eae7fa6b782ae1 Macro line was wrapped without continuation character. ok tb@

remove gcc ternary if extension ok stsp@

add support for classic diff(1) output; patch by Tom Jones

collect line type metadata when generating diff Similar to line offsets, create an array of line types (i.e., hunk, context, minus, plus) for each line output in the diff. ok stsp@

sync files from got.git 58e31a80da4f4a9e10eaea148672190f35107a47 ok stsp@

revert previous; got lib/blame.c needs diff_atom_hash_update()

make diff_atom_hash_update private to diff_atomize_text.c ok stsp@

reuse diff_atom_hash_update ok stsp@

less chatty regress ok stsp@

regress: look for the diff prog also inside obj/ ok stsp@

adjust the expected output so that regress passes again Note that test015 is still broken on OpenBSD with base patch(1). ok stsp@

ARRAY_LIST allocation optimisation Rather than realloc in fixed-sized blocks, use the 1.5 * allocated scheme when growing the array. This produces fewer allocations and up to 3x speedup on large diffs. ok stsp@

fix accounting for line endings in CRLF files There are two different subtles error in computing the end of line in diff_data_atomize_text_lines (one in per implementation, _fd and _mmap) that causes the '\n' of the '\r\n' case to be left out the current line. It causes strange bugs when diffing CRLF files, such as printing the "\ No newline at end of file" marker very often and showing the wrong offsets in the hunk headers. ok stsp@

add missing line offset information for unidiff output We forgot to generate line offset information for lines of the form: "Binary files %s and %s differ" Which is causing scrolling problems in tog's diff view. ok thomas_adam

fix a size_t multiplication overflow in diff_meyrs.c Found on an OpenBSD armv7 machine running Got regression tests: test_status_shows_no_mods_after_complete_merge Segmentation fault (core dumped) The problematic multiplication is kd_len * kd_len in diff_algo_myers() with kd_len set to 65537. (gdb) p (int)(65537 * 65537) $64 = 131073 (gdb) p (int)(65537 + 65537) $65 = 131074 (gdb) p (unsigned int)(size_t)(-1) $68 = 4294967295 (gdb) p (4294967295 / kd_len) $71 = 65535 Detect such overflow and run the fallback diff algorithm instead.

fix ed script diff output when lines are inserted at the top of a file

avoid writing just one character at a time in diff_output_lines() With input from ori@ and millert@

fix performance issues in the search for function prototypes with + ok naddy

patience: do not swallow identical neighbors This does not make much sense, because if common-unique lines swallow their neighboring ones, they count less, and another bad, shorter sequence may gain more weight than a very long sequence that was combined to just one common-unique chunk. It also much simplifies the code and avoids bugs we had to implement complex fixes for before.

set diff box recursion limit to UINT_MAX by default In practice, recursion is already limited by our Myers max-effort cut and this heuristic should generally provide a better split than a limit on the number of diff boxes. A recursion limit is only required for diff configs that do not include the Myers algorithm, which we currently don't have. Discussed with Neels

set a minimum myers effort limit to avoid an early short-cut on small files discussed with Neels

allow for telling the difference between empty and non-existent files Adjust labels used in diff output accordingly; non-existent files should have the label "/dev/null"