Commit Briefs
make diff_chunk_type() public and clarify comment
As discussed with stsp, reword an easily misunderstood comment, and move diff_chunk_type() into the public diff API to improve caller efficiency. ok stsp@
always cast ctype' is*() arguments to unsigned char
Almost all had already an unsigned argument (uint8_t or unsigned char), but cast anyway in case the types are changed in the future. ok stsp@
Don't return errno when fread fails
fread doesn't consistently set errno on failure. - On OpenBSD fread sets errno on possible argument overflows, but this doesn't occur on other platforms. rfread doesn't set errno on EOF or other failures. - ferror does not set errno on failure. Returning errno here is possibly inconsistent. Return EIO here instead. ok stsp@
diff: Add API for consumers to check if diff is printable
Programs using the libdiff API they can need to know if the diff contained anything that would be printed, or would be empty. Expose the same check that the output functions do as a function call. ok stsp@
remove gcc ternary if extension
ok stsp@
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
add sanity assertions around adding result chunks
uncovers errors related to placing minus chunks above already added plus chunks.
allow diff API users to atomize files separately
This is a breaking API change (not that we care about that at this point). This can avoid redundant work spent on atomizing a file multiple times. There are use cases where one particular file must be compared to other files over and over again, such as when blaming file history. The old API gave access to both versions of the file to the atomizer just in case a future atomizer implementation needs this. This can still be achieved by passing a second file via the atomizer's private data pointer.
rename diff_atom->d to diff_atom->root, because it always is
The idea was that for each diff box within the files, the atoms would have a backpointer to the current layer of diff_data (indicating the current section), but it is not actually needed to update the backpointer in each atom to the current diff_data. That is why the current code always points atom->d to the root diff_data for the entire file. Clarify by proper name. Constructs like atom->d->root->foo are redundant, just use atom->root->foo.