Brandon Williams <[email protected]> writes: > We have have reached the limit of the number of flags that can be stored
s/have have/have/; but bit #9 is unused. "We cannot add many more flags even if we wanted to" would be more flexible and does not take this change hostage to whatever topic that tries to claim that bit, I would think. > in a single unsigned int. In order to allow for more flags to be added > to the diff machinery in the future this patch converts the flags to be > stored in bitfields in 'struct diff_flags'. > > Signed-off-by: Brandon Williams <[email protected]> > --- > builtin/commit.c | 7 +++-- > builtin/log.c | 2 +- > diff-lib.c | 6 ++-- > diff.c | 3 +- > diff.h | 96 > +++++++++++++++++++++++++++++++++----------------------- > sequencer.c | 5 +-- > 6 files changed, 70 insertions(+), 49 deletions(-) > > diff --git a/diff.h b/diff.h > index aca150ba2..d58f06106 100644 > --- a/diff.h > +++ b/diff.h > @@ -60,42 +60,59 @@ typedef struct strbuf *(*diff_prefix_fn_t)(struct > diff_options *opt, void *data) > > #define DIFF_FORMAT_CALLBACK 0x1000 > > -#define DIFF_OPT_RECURSIVE (1 << 0) > -#define DIFF_OPT_TREE_IN_RECURSIVE (1 << 1) > -#define DIFF_OPT_BINARY (1 << 2) > -... > -#define DIFF_OPT_FUNCCONTEXT (1 << 29) > -#define DIFF_OPT_PICKAXE_IGNORE_CASE (1 << 30) > -#define DIFF_OPT_DEFAULT_FOLLOW_RENAMES (1U << 31) > - > -#define DIFF_OPT_TST(opts, flag) ((opts)->flags & DIFF_OPT_##flag) > -#define DIFF_OPT_TOUCHED(opts, flag) ((opts)->touched_flags & > DIFF_OPT_##flag) > -#define DIFF_OPT_SET(opts, flag) (((opts)->flags |= > DIFF_OPT_##flag),((opts)->touched_flags |= DIFF_OPT_##flag)) > -#define DIFF_OPT_CLR(opts, flag) (((opts)->flags &= > ~DIFF_OPT_##flag),((opts)->touched_flags |= DIFF_OPT_##flag)) > +#define DIFF_FLAGS_INIT { 0 } > +extern const struct diff_flags diff_flags_cleared; This thing is curious. Seeing the scary diff_flags_or(), I would have expected we'd have diff_flags_clear(&flags). > +struct diff_flags { > + unsigned RECURSIVE:1; > + unsigned TREE_IN_RECURSIVE:1; > + unsigned BINARY:1; > +... > + unsigned FUNCCONTEXT:1; > + unsigned PICKAXE_IGNORE_CASE:1; > + unsigned DEFAULT_FOLLOW_RENAMES:1; > +}; > + > +static inline struct diff_flags diff_flags_or(struct diff_flags a, > + struct diff_flags b) > +{ > + char *tmp_a = (char *)&a; > + char *tmp_b = (char *)&b; > + int i; > + > + for (i = 0; i < sizeof(struct diff_flags); i++) > + tmp_a[i] |= tmp_b[i]; > + > + return a; > +} This is doubly scary, but let's see why we need it by looking at the callers. > +#define DIFF_OPT_TST(opts, flag) ((opts)->flags.flag) > +#define DIFF_OPT_TOUCHED(opts, flag) ((opts)->touched_flags.flag) > +#define DIFF_OPT_SET(opts, flag) (((opts)->flags.flag = > 1),((opts)->touched_flags.flag = 1)) > +#define DIFF_OPT_CLR(opts, flag) (((opts)->flags.flag = > 0),((opts)->touched_flags.flag = 1)) These are trivial and straight-forward. > + > #define DIFF_XDL_TST(opts, flag) ((opts)->xdl_opts & XDF_##flag) > #define DIFF_XDL_SET(opts, flag) ((opts)->xdl_opts |= XDF_##flag) > #define DIFF_XDL_CLR(opts, flag) ((opts)->xdl_opts &= ~XDF_##flag) > @@ -122,8 +139,8 @@ struct diff_options { > const char *a_prefix, *b_prefix; > const char *line_prefix; > size_t line_prefix_length; > - unsigned flags; > - unsigned touched_flags; > + struct diff_flags flags; > + struct diff_flags touched_flags; > > /* diff-filter bits */ > unsigned int filter; > @@ -388,7 +405,8 @@ extern int diff_result_code(struct diff_options *, int); > > extern void diff_no_index(struct rev_info *, int, const char **); > > -extern int index_differs_from(const char *def, int diff_flags, int > ita_invisible_in_index); > +extern int index_differs_from(const char *def, struct diff_flags flags, > + int ita_invisible_in_index); OK. I tend to think twice before passing any struct by value (even something that starts its life as a small/single-word struct), but let's see how much simpler this allows callers to become. > diff --git a/builtin/commit.c b/builtin/commit.c > index d75b3805e..de08c2594 100644 > --- a/builtin/commit.c > +++ b/builtin/commit.c > @@ -912,11 +912,12 @@ static int prepare_to_commit(const char *index_file, > const char *prefix, > * submodules which were manually staged, which would > * be really confusing. > */ > - int diff_flags = DIFF_OPT_OVERRIDE_SUBMODULE_CONFIG; > + struct diff_flags flags = DIFF_FLAGS_INIT; > + flags.OVERRIDE_SUBMODULE_CONFIG = 1; > if (ignore_submodule_arg && > !strcmp(ignore_submodule_arg, "all")) > - diff_flags |= DIFF_OPT_IGNORE_SUBMODULES; This couldn't have been done in patches 1+2/3 because DIFF_OPT_SET() does not take a bare 'flags' but diffopt itself, which was a bit unfortunate, but the end result after this step becomes a lot more sensible. > - commitable = index_differs_from(parent, diff_flags, 1); > + flags.IGNORE_SUBMODULES = 1; > + commitable = index_differs_from(parent, flags, 1); OK. > diff --git a/builtin/log.c b/builtin/log.c > index d81a09051..780975ed4 100644 > --- a/builtin/log.c > +++ b/builtin/log.c > @@ -134,7 +134,7 @@ static void cmd_log_init_defaults(struct rev_info *rev) > > if (default_date_mode) > parse_date_format(default_date_mode, &rev->date_mode); > - rev->diffopt.touched_flags = 0; > + rev->diffopt.touched_flags = diff_flags_cleared; So this structure assignment is a more kosher way to clear everything than memset(&touched_flags, '\0', sizeof(...)); I'd still prefer diff_flags_clear(&rev->diffopt.touched_flags); tough, as it is easy to forget diff_flags_cleared is a singleton constant specifically created to be assigned for clearing another flags struct. > @@ -546,7 +546,7 @@ int index_differs_from(const char *def, int diff_flags, > setup_revisions(0, NULL, &rev, &opt); > DIFF_OPT_SET(&rev.diffopt, QUICK); > DIFF_OPT_SET(&rev.diffopt, EXIT_WITH_STATUS); > - rev.diffopt.flags |= diff_flags; > + rev.diffopt.flags = diff_flags_or(rev.diffopt.flags, flags); In a more general case, we cannot know what flags setup_revisions() gave to rev.diffopt, and because of that we cannot do rev.diffopt.flags = diff_flags; DIFF_OPT_SET(&rev.diffopt, QUICK); DIFF_OPT_SET(&rev.diffopt, EXIT_WITH_STATUS); without using the flags_or() thing. In this codepath, that currently is not a problem (because we give ac/av = 0/NULL), but it probably is a good idea to avoid depending on that. I still haven't brought myself to like the structure being passed by value and the singleton diff_flags_cleared thing, but I suspect that we may get used to them once we start using these. I dunno. Thanks.
