[PATCH v4 3/9] commit-graph: refactor compute_topological_levels()
- From
Derrick Stolee via GitGitGadget <gitgitgadget@gmail.com>
- Date
- Mar 20, 2023, 11:26 UTC
- Message-ID
- <79a57f30a850177ce6400b9e898f24981635541a.1679311616.git.gitgitgadget@gmail.com>
- In-Reply-To
- <pull.1489.v4.git.1679311615.gitgitgadget@gmail.com>
From: Derrick Stolee <derrickstolee@github.com>
This patch extracts the common code used to compute topological levels and corrected committer dates into a common routine, compute_reachable_generation_numbers(). For ease of reading, it only modifies compute_topological_levels() to use this new routine, leaving compute_generation_numbers() to be modified in the next change.
This new routine dispatches to call the necessary functions to get and set the generation number for a given commit through a vtable (the compute_generation_info struct).
Computing the generation number itself is done in compute_generation_from_max(), which dispatches its implementation based on the generation version requested, or issuing a BUG() for unrecognized generation versions. This does not use a vtable because the logic depends only on the generation number version, not where the data is being loaded from or being stored to. This is a subtle point that will make more sense in a future change that modifies the in-memory generation values instead of just preparing values for writing to a commit-graph file.
This change looks like it adds a lot of new code. However, two upcoming changes will be quite small due to the work being done in this change.
Co-authored-by: Taylor Blau <me@ttaylorr.com> Signed-off-by: Taylor Blau <me@ttaylorr.com> Signed-off-by: Derrick Stolee <derrickstolee@github.com> --- commit-graph.c | 106 ++++++++++++++++++++++++++++++++++++++----------- 1 file changed, 83 insertions(+), 23 deletions(-)
diff --git a/commit-graph.c b/commit-graph.c index c11b59f28b3..4356c8c1f4b 100644 --- a/commit-graph.c +++ b/commit-graph.c @@ -1446,24 +1446,52 @@ static void close_reachable(struct write_commit_graph_context *ctx) stop_progress(&ctx->progress); } -static void compute_topological_levels(struct write_commit_graph_context *ctx) +struct compute_generation_info { + struct repository *r; + struct packed_commit_list *commits; + struct progress *progress; + int progress_cnt; + + timestamp_t (*get_generation)(struct commit *c, void *data); + void (*set_generation)(struct commit *c, timestamp_t gen, void *data); + void *data; +}; + +static timestamp_t compute_generation_from_max(struct commit *c, + timestamp_t max_gen, + int generation_version) +{ + switch (generation_version) { + case 1: /* topological levels */ + if (max_gen > GENERATION_NUMBER_V1_MAX - 1) + max_gen = GENERATION_NUMBER_V1_MAX - 1; + return max_gen + 1; + + case 2: /* corrected commit date */ + if (c->date && c->date > max_gen) + max_gen = c->date - 1; + return max_gen + 1; + + default: + BUG("attempting unimplemented version"); + } +} + +static void compute_reachable_generation_numbers( + struct compute_generation_info *info, + int generation_version) { int i; struct commit_list *list = NULL; - if (ctx->report_progress) - ctx->progress = start_delayed_progress( - _("Computing commit graph topological levels"), - ctx->commits.nr); - for (i = 0; i < ctx->commits.nr; i++) { - struct commit *c = ctx->commits.list[i]; - uint32_t level; - - repo_parse_commit(ctx->r, c); - level = *topo_level_slab_at(ctx->topo_levels, c); + for (i = 0; i < info->commits->nr; i++) { + struct commit *c = info->commits->list[i]; + timestamp_t gen; + repo_parse_commit(info->r, c); + gen = info->get_generation(c, info->data); + display_progress(info->progress, info->progress_cnt + 1); - display_progress(ctx->progress, i + 1); - if (level != GENERATION_NUMBER_ZERO) + if (gen != GENERATION_NUMBER_ZERO && gen != GENERATION_NUMBER_INFINITY) continue; commit_list_insert(c, &list); @@ -1471,31 +1499,63 @@ static void compute_topological_levels(struct write_commit_graph_context *ctx) struct commit *current = list->item; struct commit_list *parent; int all_parents_computed = 1; - uint32_t max_level = 0; + uint32_t max_gen = 0; for (parent = current->parents; parent; parent = parent->next) { - repo_parse_commit(ctx->r, parent->item); - level = *topo_level_slab_at(ctx->topo_levels, parent->item); + repo_parse_commit(info->r, parent->item); + gen = info->get_generation(parent->item, info->data); - if (level == GENERATION_NUMBER_ZERO) { + if (gen == GENERATION_NUMBER_ZERO) { all_parents_computed = 0; commit_list_insert(parent->item, &list); break; } - if (level > max_level) - max_level = level; + if (gen > max_gen) + max_gen = gen; } if (all_parents_computed) { pop_commit(&list); - - if (max_level > GENERATION_NUMBER_V1_MAX - 1) - max_level = GENERATION_NUMBER_V1_MAX - 1; - *topo_level_slab_at(ctx->topo_levels, current) = max_level + 1; + gen = compute_generation_from_max( + current, max_gen, + generation_version); + info->set_generation(current, gen, info->data); } } } +} + +static timestamp_t get_topo_level(struct commit *c, void *data) +{ + struct write_commit_graph_context *ctx = data; + return *topo_level_slab_at(ctx->topo_levels, c); +} + +static void set_topo_level(struct commit *c, timestamp_t t, void *data) +{ + struct write_commit_graph_context *ctx = data; + *topo_level_slab_at(ctx->topo_levels, c) = (uint32_t)t; +} + +static void compute_topological_levels(struct write_commit_graph_context *ctx) +{ + struct compute_generation_info info = { + .r = ctx->r, + .commits = &ctx->commits, + .get_generation = get_topo_level, + .set_generation = set_topo_level, + .data = ctx, + }; + + if (ctx->report_progress) + info.progress = ctx->progress + = start_delayed_progress( + _("Computing commit graph topological levels"), + ctx->commits.nr); + + compute_reachable_generation_numbers(&info, 1); + stop_progress(&ctx->progress); }
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