From mboxrd@z Thu Jan 1 00:00:00 1970 From: jon@blackcubes.dyndns.org Subject: [PATCH] git-rev-list --merge-order resynched with Linus' head Date: 5 Jun 2005 07:23:36 -0000 Message-ID: <20050605072336.14283.qmail@blackcubes.dyndns.org> X-From: git-owner@vger.kernel.org Sun Jun 05 09:22:11 2005 Return-path: Received: from vger.kernel.org ([12.107.209.244]) by ciao.gmane.org with esmtp (Exim 4.43) id 1DepSR-0006i7-Ty for gcvg-git@gmane.org; Sun, 05 Jun 2005 09:22:08 +0200 Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S261265AbVFEHZW (ORCPT ); Sun, 5 Jun 2005 03:25:22 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S261493AbVFEHZW (ORCPT ); Sun, 5 Jun 2005 03:25:22 -0400 Received: from 203-166-247-224.dyn.iinet.net.au ([203.166.247.224]:7042 "HELO blackcubes.dyndns.org") by vger.kernel.org with SMTP id S261265AbVFEHXk (ORCPT ); Sun, 5 Jun 2005 03:23:40 -0400 Received: (qmail 14284 invoked by uid 500); 5 Jun 2005 07:23:36 -0000 To: git@vger.kernel.org, jon.seymour@gmail.com, torvalds@osdl.org Sender: git-owner@vger.kernel.org Precedence: bulk X-Mailing-List: git@vger.kernel.org [PATCH] Modify git-rev-list to linearise the commit history in merge order. This patch linearises the GIT commit history graph into merge order which is defined by invariants specified in Documentation/git-rev-list.txt. The linearisation produced by this patch is superior in an objective sense to that produced by the existing git-rev-list implementation in that the linearisation produced is guaranteed to have the minimum number of discontinuities, where a discontinuity is defined as an adjacent pair of commits in the output list which are not related in a direct child-parent relationship. With this patch a graph like this: a4 --- | \ \ | b4 | |/ | | a3 | | | | | a2 | | | | c3 | | | | | c2 | b3 | | | /| | b2 | | | c1 | | / | b1 a1 | | | a0 | | / root Sorts like this: = a4 | c3 | c2 | c1 ^ b4 | b3 | b2 | b1 ^ a3 | a2 | a1 | a0 = root Instead of this: = a4 | c3 ^ b4 | a3 ^ c2 ^ b3 ^ a2 ^ b2 ^ c1 ^ a1 ^ b1 ^ a0 = root A test script, t/t6000-rev-list.sh, includes a test which demonstrates that the linearisation produced by --merge-order has less discontinuities than the linearisation produced by git-rev-list without the --merge-order flag specified. To see this, do the following: cd t ./t6000-rev-list.sh cd trash cat actual-default-order cat actual-merge-order The existing behaviour of git-rev-list is preserved, by default. To obtain the modified behaviour, specify --merge-order or --merge-order --show-breaks on the command line. This version of the patch has been tested on the git repository and also on the linux-2.6 repository and has reasonable performance on both - ~50-100% slower than the original algorithm. This version of the patch has incorporated a functional equivalent of the Linus' output limiting algorithm into the merge-order algorithm itself. This operates per the notes associated with Linus' commit 337cb3fb8da45f10fe9a0c3cf571600f55ead2ce. For more details about this change, refer to Documentation/git-rev-list.txt and http://blackcubes.dyndns.org/epoch/. Signed-off-by: Jon Seymour Diverged from 337cb3fb8da45f10fe9a0c3cf571600f55ead2ce by Linus Torvalds --- diff --git a/Documentation/git-rev-list.txt b/Documentation/git-rev-list.txt --- a/Documentation/git-rev-list.txt +++ b/Documentation/git-rev-list.txt @@ -9,7 +9,7 @@ git-rev-list - Lists commit objects in r SYNOPSIS -------- -'git-rev-list' +'git-rev-list' [ *--max-count*=number ] [ *--max-age*=timestamp ] [ *--min-age*=timestamp ] [ *--merge-order* [ *--show-breaks* ] ] DESCRIPTION ----------- @@ -17,11 +17,39 @@ Lists commit objects in reverse chronolo given commit, taking ancestry relationship into account. This is useful to produce human-readable log output. +If *--merge-order* is specified, the commit history is decomposed into a unique sequence of minimal, non-linear +epochs and maximal, linear epochs. Non-linear epochs are then linearised by sorting them into merge order, which +is described below. + +Maximal, linear epochs correspond to periods of sequential development. Minimal, non-linear epochs +correspond to periods of divergent development followed by a converging merge. The theory of epochs is described +in more detail at link:http://blackcubes.dyndns.org/epoch/[http://blackcubes.dyndns.org/epoch/]. + +The merge order for a non-linear epoch is defined as a linearisation for which the following invariants are true: + + 1. if a commit P is reachable from commit N, commit P sorts after commit N in the linearised list. + 2. if Pi and Pj are any two parents of a merge M (with i < j), then any commit N, such that N is reachable from Pj + but not reachable from Pi, sorts before all commits reachable from Pi. + +Invariant 1 states that later commits appear before earlier commits they are derived from. + +Invariant 2 states that commits unique to "later" parents in a merge, appear before all commits from "earlier" parents of +a merge. + +If *--show-breaks* is specified, each item of the list is output with a 2-character prefix consisting of one of: + (|), (^), (=) followed by a space. +Commits marked with (=) represent the boundaries of minimal, non-linear epochs and correspond either to the start of a period of divergent development or to the end of such a period. +Commits marked with (|) are direct parents of commits immediately preceding the marked commit in the list. +Commits marked with (^) are not parents of the immediately preceding commit. These "breaks" represent necessary discontinuities implied by trying to represent an arbtirary DAG in a linear form. + +*--show-breaks* is only valid if *--merge-order* is also specified. Author ------ Written by Linus Torvalds +Original *--merge-order* logic by Jon Seymour + Documentation -------------- Documentation by David Greaves, Junio C Hamano and the git-list . diff --git a/Makefile b/Makefile --- a/Makefile +++ b/Makefile @@ -40,9 +40,9 @@ install: $(PROG) $(SCRIPTS) $(INSTALL) $(PROG) $(SCRIPTS) $(dest)$(bin) LIB_OBJS=read-cache.o sha1_file.o usage.o object.o commit.o tree.o blob.o \ - tag.o delta.o date.o index.o diff-delta.o patch-delta.o + tag.o delta.o date.o index.o diff-delta.o patch-delta.o epoch.o LIB_FILE=libgit.a -LIB_H=cache.h object.h blob.h tree.h commit.h tag.h delta.h +LIB_H=cache.h object.h blob.h tree.h commit.h tag.h delta.h epoch.h LIB_H += strbuf.h LIB_OBJS += strbuf.o @@ -134,6 +134,7 @@ diffcore-pathspec.o : $(LIB_H) diffcore. diffcore-pickaxe.o : $(LIB_H) diffcore.h diffcore-break.o : $(LIB_H) diffcore.h diffcore-order.o : $(LIB_H) diffcore.h +epoch.o: $(LIB_H) test: all $(MAKE) -C t/ all diff --git a/commit.c b/commit.c --- a/commit.c +++ b/commit.c @@ -129,7 +129,7 @@ void free_commit_list(struct commit_list } } -static void insert_by_date(struct commit_list **list, struct commit *item) +void insert_by_date(struct commit_list **list, struct commit *item) { struct commit_list **pp = list; struct commit_list *p; @@ -254,3 +254,25 @@ unsigned long pretty_print_commit(const buf[offset] = '\0'; return offset; } + +struct commit *pop_commit(struct commit_list **stack) +{ + struct commit_list *top = *stack; + struct commit *item = top ? top->item : NULL; + + if (top) { + *stack = top->next; + free(top); + } + return item; +} + +int count_parents(struct commit * commit) +{ + int count = 0; + struct commit_list * parents = commit->parents; + for (count=0;parents; parents=parents->next,count++) + ; + return count; +} + diff --git a/commit.h b/commit.h --- a/commit.h +++ b/commit.h @@ -32,6 +32,8 @@ void free_commit_list(struct commit_list void sort_by_date(struct commit_list **list); +void insert_by_date(struct commit_list **list, struct commit *item); + extern unsigned long pretty_print_commit(const char *msg, unsigned long len, char *buf, unsigned long space); @@ -41,4 +43,7 @@ extern unsigned long pretty_print_commit struct commit *pop_most_recent_commit(struct commit_list **list, unsigned int mark); +struct commit *pop_commit(struct commit_list **stack); + +int count_parents(struct commit * commit); #endif /* COMMIT_H */ diff --git a/epoch.c b/epoch.c new file mode 100644 --- /dev/null +++ b/epoch.c @@ -0,0 +1,568 @@ +/* + * Copyright (c) 2005, Jon Seymour + * + * For more information about epoch theory on which this module is based, + * refer to http://blackcubes.dyndns.org/epoch/. That web page defines + * terms such as "epoch" and "minimal, non-linear epoch" and provides rationales + * for some of the algorithms used here. + * + */ +#include +#include // provides arbitrary precision integers required to accurately represent fractional mass +#include "cache.h" +#include "commit.h" +#include "epoch.h" + +struct fraction { + BIGNUM numerator; + BIGNUM denominator; +}; + +#define HAS_EXACTLY_ONE_PARENT(n) ((n)->parents && !(n)->parents->next) + +static BN_CTX *context = NULL; +static struct fraction *one = NULL; +static struct fraction *zero = NULL; + +static BN_CTX *get_BN_CTX() +{ + if (!context) { + context = BN_CTX_new(); + } + return context; +} + +static struct fraction *new_zero() +{ + struct fraction *result = xmalloc(sizeof(*result)); + BN_init(&result->numerator); + BN_init(&result->denominator); + BN_zero(&result->numerator); + BN_one(&result->denominator); + return result; +} + +static void clear_fraction(struct fraction *fraction) +{ + BN_clear(&fraction->numerator); + BN_clear(&fraction->denominator); +} + +static struct fraction *divide(struct fraction *result, struct fraction *fraction, int divisor) +{ + BIGNUM bn_divisor; + + BN_init(&bn_divisor); + BN_set_word(&bn_divisor, divisor); + + BN_copy(&result->numerator, &fraction->numerator); + BN_mul(&result->denominator, &fraction->denominator, &bn_divisor, get_BN_CTX()); + + BN_clear(&bn_divisor); + return result; +} + +static struct fraction *init_fraction(struct fraction *fraction) +{ + BN_init(&fraction->numerator); + BN_init(&fraction->denominator); + BN_zero(&fraction->numerator); + BN_one(&fraction->denominator); + return fraction; +} + +static struct fraction *get_one() +{ + if (!one) { + one = new_zero(); + BN_one(&one->numerator); + } + return one; +} + +static struct fraction *get_zero() +{ + if (!zero) { + zero = new_zero(); + } + return zero; +} + +static struct fraction *copy(struct fraction *to, struct fraction *from) +{ + BN_copy(&to->numerator, &from->numerator); + BN_copy(&to->denominator, &from->denominator); + return to; +} + +static struct fraction *add(struct fraction *result, struct fraction *left, struct fraction *right) +{ + BIGNUM a, b, gcd; + + BN_init(&a); + BN_init(&b); + BN_init(&gcd); + + BN_mul(&a, &left->numerator, &right->denominator, get_BN_CTX()); + BN_mul(&b, &left->denominator, &right->numerator, get_BN_CTX()); + BN_mul(&result->denominator, &left->denominator, &right->denominator, get_BN_CTX()); + BN_add(&result->numerator, &a, &b); + + BN_gcd(&gcd, &result->denominator, &result->numerator, get_BN_CTX()); + BN_div(&result->denominator, NULL, &result->denominator, &gcd, get_BN_CTX()); + BN_div(&result->numerator, NULL, &result->numerator, &gcd, get_BN_CTX()); + + BN_clear(&a); + BN_clear(&b); + BN_clear(&gcd); + + return result; +} + +static int compare(struct fraction *left, struct fraction *right) +{ + BIGNUM a, b; + + int result; + + BN_init(&a); + BN_init(&b); + + BN_mul(&a, &left->numerator, &right->denominator, get_BN_CTX()); + BN_mul(&b, &left->denominator, &right->numerator, get_BN_CTX()); + + result = BN_cmp(&a, &b); + + BN_clear(&a); + BN_clear(&b); + + return result; +} + +struct mass_counter { + struct fraction seen; + struct fraction pending; +}; + +static struct mass_counter *new_mass_counter(struct commit *commit, struct fraction *pending) +{ + struct mass_counter *mass_counter = xmalloc(sizeof(*mass_counter)); + memset(mass_counter, 0, sizeof(*mass_counter)); + + init_fraction(&mass_counter->seen); + init_fraction(&mass_counter->pending); + + copy(&mass_counter->pending, pending); + copy(&mass_counter->seen, get_zero()); + + if (commit->object.util) { + die("multiple attempts to initialize mass counter for %s\n", sha1_to_hex(commit->object.sha1)); + } + + commit->object.util = mass_counter; + + return mass_counter; +} + +static void free_mass_counter(struct mass_counter *counter) +{ + clear_fraction(&counter->seen); + clear_fraction(&counter->pending); + free(counter); +} + +static int find_base_for_list(struct commit_list *list, struct commit **boundary) +{ + + int ret = 0; + + struct commit_list *cleaner = NULL; + struct commit_list *pending = NULL; + struct commit *head = (list->next ? NULL : list->item); + + *boundary = NULL; + + struct fraction injected; + + init_fraction(&injected); + + for (; list; list = list->next) { + if (!(list->item->object.flags & UNINTERESTING)) { + new_mass_counter(list->item, get_one()); + commit_list_insert(list->item, &cleaner); + commit_list_insert(list->item, &pending); + add(&injected, &injected, get_one()); + } + } + + while (!*boundary && pending && !ret) { + + struct commit *latest = pop_commit(&pending); + struct mass_counter *latest_node = (struct mass_counter *) latest->object.util; + + if ((ret = parse_commit(latest))) + continue; + + add(&latest_node->seen, &latest_node->seen, &latest_node->pending); + + int num_parents = count_parents(latest); + + if (num_parents) { + + struct fraction distribution; + + divide(init_fraction(&distribution), &latest_node->pending, num_parents); + + struct commit_list *parents; + + for (parents = latest->parents; parents; parents = parents->next) { + struct commit *parent = parents->item; + struct mass_counter *parent_node = (struct mass_counter *) parent->object.util; + if (!parent_node) { + parent_node = new_mass_counter(parent, &distribution); + commit_list_insert(parent, &cleaner); + insert_by_date(&pending, parent); + } else { + if (!compare(&parent_node->pending, get_zero())) { + copy(&parent_node->pending, &distribution); + insert_by_date(&pending, parent); + } else { + add(&parent_node->pending, &parent_node->pending, &distribution); + } + } + } + } + + if (!compare(&latest_node->seen, &injected) && (latest != head)) { + // if this node has seen one unit of mass, it must be the base, so mark + // the boundary which will cause the loop to stop. + *boundary = latest; + } + + copy(&latest_node->pending, get_zero()); + + } + + for (; cleaner;) { + struct commit *next = pop_commit(&cleaner); + if (!next->object.util) { + die("unexpected NULL pointer found in %s @ line %d", __FILE__, __LINE__); + } + free_mass_counter((struct mass_counter *) next->object.util); + next->object.util = NULL; + } + + if (pending) + free_commit_list(pending); + + return ret; + +} + + +// +// Finds the base node of an epoch. +// +// This algorithm uses a conservation of mass approach. +// +// The head starts with a weight of 1 and distributes equal portions +// along each edge to each of its parents. The process continues until +// one node discovers that it has acquired a total mass of 1 from its +// descendents. This node is the base node. +// +// Importantly the queue of nodes to be processed is sorted in +// reverse date order and each node occupies at most one +// position in the queue simultaneously. These two properties +// do not effect the algorithm's correctness. However assuming most, but +// not all, timestamps are sane they do prevent the algorithm becoming +// exponential by ensuring that most nodes are only visited once. +// This is true because mass is only propagated through the network +// when we are pretty sure we are not going to see any more coming +// our way. The occasional bad timestamp will mean that we are +// wrong, occasionally, but this does not matter too much. +// +static int find_base(struct commit *head, struct commit **boundary) +{ + int ret = 0; + + struct commit_list *pending = NULL; + + commit_list_insert(head, &pending); + + ret = find_base_for_list(pending, boundary); + + free_commit_list(pending); + + return ret; +} + +// +// This procedure traverses to the boundary of the first epoch in the epoch +// sequence of the epoch headed at head_of_epoch. This is either the end of +// the maximal linear epoch or the base of a minimal non-linear epoch. +// +// The queue of pending nodes is sorted in reverse date order and each node +// is currently in the queue at most once. +// +static int find_next_epoch_boundary(struct commit *head_of_epoch, struct commit **boundary) +{ + int ret; + struct commit *item = head_of_epoch; + + ret = parse_commit(item); + if (ret) + return ret; + + if (HAS_EXACTLY_ONE_PARENT(item)) { + + // we are at the start of a maximimal linear epoch .. traverse to the end + + // traverse to the end of a maximal linear epoch + while (HAS_EXACTLY_ONE_PARENT(item) && !ret) { + item = item->parents->item; + ret = parse_commit(item); + } + *boundary = item; + + } else { + + // otherwise, we are at the start of a minimal, non-linear + // epoch - find the common base of all parents. + + ret = find_base(item, boundary); + + } + + return ret; +} + +// +// Returns non-zero if parent is known to be a parent of child. +// +static int is_parent_of(struct commit *parent, struct commit *child) +{ + struct commit_list *parents; + for (parents = child->parents; parents; parents = parents->next) { + if (!memcmp(parent->object.sha1, parents->item->object.sha1, sizeof(parents->item->object.sha1))) + return 1; + } + return 0; +} + +static void push_onto_merge_order_stack(struct commit_list **stack, struct commit *item) +{ + struct commit_list *top = *stack; + if (top && (top->item->object.flags & MERGE_ORDER_BREAK_FLAG)) { + if (is_parent_of(top->item, item)) { + top->item->object.flags &= ~MERGE_ORDER_BREAK_FLAG; + } + } + commit_list_insert(item, stack); +} + +// +// Sorts the nodes of the first epoch of the epoch sequence of the epoch headed at head +// into merge order. +// +static void sort_first_epoch(struct commit *head, struct commit_list **stack) +{ + struct commit_list *parents; + struct commit_list *reversed_parents = NULL; + + head->object.flags |= MERGE_ORDER_VISIT_FLAG; + + + // + // parse_commit builds the parent list in reverse order with respect to the order of + // the git-commit-tree arguments. + // + // so we need to reverse this list to output the oldest (or most "local") commits last. + // + + for (parents = head->parents; parents; parents = parents->next) + commit_list_insert(parents->item, &reversed_parents); + + // + // todo: by sorting the parents in a different order, we can alter the + // merge order to show contemporaneous changes in parallel branches + // occurring after "local" changes. This is useful for a developer + // when a developer wants to see all changes that were incorporated + // into the same merge as her own changes occur after her own + // changes. + // + + for (; reversed_parents;) { + + struct commit *parent = pop_commit(&reversed_parents); + + if (head->object.flags & UNINTERESTING) { + parent->object.flags |= UNINTERESTING; + } + + if (!(parent->object.flags & MERGE_ORDER_VISIT_FLAG)) { + if (parent->object.flags & MERGE_ORDER_EPOCH_FLAG) { + if (*stack) { + die("something else is on the stack - %s\n", sha1_to_hex((*stack)->item->object.sha1)); + } + push_onto_merge_order_stack(stack, parent); + parent->object.flags |= MERGE_ORDER_VISIT_FLAG; + } else { + + sort_first_epoch(parent, stack); + + if (reversed_parents) { + // + // this indicates a possible discontinuity + // it may not be be actual discontinuity if + // the head of parent N happens to be the tail + // of parent N+1 + // + // the next push onto the stack will resolve the question + // + (*stack)->item->object.flags |= MERGE_ORDER_BREAK_FLAG; + } + } + } + } + + push_onto_merge_order_stack(stack, head); +} + +// +// Sorts an arbitrary epoch into merge order by sorting each epoch +// of its epoch sequence into order. +// +// Note: this algorithm currently leaves traces of its execution in the +// object flags of nodes it discovers. This should probably be fixed. +// +static int sort_in_merge_order(struct commit *head_of_epoch, emitter_func emitter) +{ + struct commit *next; + int ret = 0; + int stop = 0; + unsigned int flags_seen = 0; + + ret = parse_commit(head_of_epoch); + + for (next = head_of_epoch; next && next->parents && !ret && !stop;) { + + struct commit *base = NULL; + unsigned int uninteresting = 0; + + + ret = find_next_epoch_boundary(next, &base); + if (ret) + return ret; + + next->object.flags |= MERGE_ORDER_EPOCH_FLAG; + if (base) { + base->object.flags |= MERGE_ORDER_EPOCH_FLAG; + } + + if (HAS_EXACTLY_ONE_PARENT(next)) { + + while (HAS_EXACTLY_ONE_PARENT(next) && !stop && !ret) { + next->object.flags |= (uninteresting |= (next->object.flags & UNINTERESTING)); + stop = (*emitter) (next); + next = next->parents->item; + ret = parse_commit(next); + } + + } else { + + struct commit_list *stack = NULL; + sort_first_epoch(next, &stack); + while (stack && !stop) { + next = pop_commit(&stack); + + if (next->object.flags & MERGE_ORDER_BREAK_FLAG) { + uninteresting = (next->object.flags & UNINTERESTING); + } else { + next->object.flags |= (uninteresting |= (next->object.flags & UNINTERESTING)); + } + + flags_seen |= next->object.flags; + if (stack) { + stop = (*emitter) (next); + } + } + if (stack) { + free_commit_list(stack); + } + stop = stop || (flags_seen & UNINTERESTING); + } + + } + + if (next && !stop) { + stop = (*emitter) (next); + } + + return ret; +} + +int sort_list_in_merge_order(struct commit_list *list, emitter_func emitter) +{ + struct commit_list *stack = NULL; + struct commit *base; + struct commit *next; + unsigned int flags_seen = 0; + int ret = 0; + int stop = 0; + + if (!list->next) { + + base = list->item; + + } else { + + if ((ret = find_base_for_list(list, &base))) + return ret; + + if (base) { + base->object.flags |= MERGE_ORDER_EPOCH_FLAG; + } + + struct commit_list *reversed = NULL; + + for (; list; list = list->next) + commit_list_insert(list->item, &reversed); + + while (reversed) { + sort_first_epoch(pop_commit(&reversed), &stack); + if (reversed) { + // this may or may not be a break - see sort_first_epoch + stack->item->object.flags |= MERGE_ORDER_BREAK_FLAG; + } + } + + unsigned int uninteresting = 0; + + while (stack && !stop) { + + next = pop_commit(&stack); + + if (next->object.flags & MERGE_ORDER_BREAK_FLAG) { + uninteresting = (next->object.flags & UNINTERESTING); + } else { + next->object.flags |= (uninteresting |= (next->object.flags & UNINTERESTING)); + } + + flags_seen |= next->object.flags; + + if (stack) { + stop = (*emitter) (next); + } + } + + if (stack) { + free_commit_list(stack); + } + } + + if (!stop && base && !(flags_seen & UNINTERESTING)) { + ret = sort_in_merge_order(base, emitter); + } + + return ret; +} diff --git a/epoch.h b/epoch.h new file mode 100644 --- /dev/null +++ b/epoch.h @@ -0,0 +1,13 @@ +#ifndef EPOCH_H +#define EPOCH_H + +typedef int (*emitter_func) (struct commit *); + +int sort_list_in_merge_order(struct commit_list *list, emitter_func emitter); + +#define UNINTERESTING (1u<<2) +#define MERGE_ORDER_EPOCH_FLAG (1u<<3) +#define MERGE_ORDER_VISIT_FLAG (1u<<4) +#define MERGE_ORDER_BREAK_FLAG (1u<<5) + +#endif /* EPOCH_H */ diff --git a/object.h b/object.h --- a/object.h +++ b/object.h @@ -15,6 +15,7 @@ struct object { const char *type; struct object_list *refs; struct object_list *attached_deltas; + void *util; }; extern int nr_objs; diff --git a/rev-list.c b/rev-list.c --- a/rev-list.c +++ b/rev-list.c @@ -1,9 +1,9 @@ #include "cache.h" #include "commit.h" +#include "epoch.h" #define SEEN (1u << 0) #define INTERESTING (1u << 1) -#define UNINTERESTING (1u << 2) static const char rev_list_usage[] = "usage: git-rev-list [OPTION] commit-id \n" @@ -11,7 +11,8 @@ static const char rev_list_usage[] = " --max-age=epoch\n" " --min-age=epoch\n" " --header\n" - " --pretty"; + " --pretty\n" + " --merge-order [ --show-breaks ]"; static int verbose_header = 0; static int show_parents = 0; @@ -21,27 +22,49 @@ static const char *prefix = ""; static unsigned long max_age = -1; static unsigned long min_age = -1; static int max_count = -1; +static int merge_order = 0; +static int show_breaks = 0; -static void show_commit(struct commit *commit) +static int show_commit(struct commit *commit) { - printf("%s%s", prefix, sha1_to_hex(commit->object.sha1)); - if (show_parents) { - struct commit_list *parents = commit->parents; - while (parents) { - printf(" %s", sha1_to_hex(parents->item->object.sha1)); - parents = parents->next; - } - } - putchar('\n'); - if (verbose_header) { - const char *buf = commit->buffer; - if (pretty_print) { - static char pretty_header[16384]; - pretty_print_commit(commit->buffer, ~0, pretty_header, sizeof(pretty_header)); - buf = pretty_header; - } - printf("%s%c", buf, hdr_termination); + if (commit->object.flags & UNINTERESTING) + return 0; + if (min_age != -1 && (commit->date > min_age)) + return 0; + if (max_age != -1 && (commit->date < max_age)) + return 1; + if (max_count != -1 && !max_count--) + return 1; + + if (!show_breaks) { + printf("%s%s", prefix, sha1_to_hex(commit->object.sha1)); + if (show_parents) { + struct commit_list *parents = commit->parents; + while (parents) { + printf(" %s", sha1_to_hex(parents->item->object.sha1)); + parents = parents->next; + } + } + putchar('\n'); + if (verbose_header) { + const char *buf = commit->buffer; + if (pretty_print) { + static char pretty_header[16384]; + pretty_print_commit(commit->buffer, ~0, pretty_header, sizeof(pretty_header)); + buf = pretty_header; + } + printf("%s%c", buf, hdr_termination); + } + } else { + char c='|'; + if (commit->object.flags & MERGE_ORDER_BREAK_FLAG) { + c = '^'; + } else if (commit->object.flags & MERGE_ORDER_EPOCH_FLAG) { + c = '='; + } + printf("%c %s\n", c, sha1_to_hex(commit->object.sha1)); } + return 0; } static void show_commit_list(struct commit_list *list) @@ -49,15 +72,8 @@ static void show_commit_list(struct comm while (list) { struct commit *commit = pop_most_recent_commit(&list, SEEN); - if (commit->object.flags & UNINTERESTING) - continue; - if (min_age != -1 && (commit->date > min_age)) - continue; - if (max_age != -1 && (commit->date < max_age)) - break; - if (max_count != -1 && !max_count--) - break; - show_commit(commit); + if (show_commit(commit)) + break; } } @@ -141,6 +157,14 @@ int main(int argc, char **argv) show_parents = 1; continue; } + if (!strncmp(arg, "--merge-order", 13)) { + merge_order = 1; + continue; + } + if (!strncmp(arg, "--show-breaks", 13)) { + show_breaks = 1; + continue; + } flags = 0; if (*arg == '^') { @@ -148,7 +172,7 @@ int main(int argc, char **argv) arg++; limited = 1; } - if (get_sha1(arg, sha1)) + if (get_sha1(arg, sha1) || (show_breaks && !merge_order)) usage(rev_list_usage); commit = lookup_commit_reference(sha1); if (!commit || parse_commit(commit) < 0) @@ -160,9 +184,18 @@ int main(int argc, char **argv) if (!list) usage(rev_list_usage); - if (limited) - list = limit_list(list); - show_commit_list(list); + + if (!merge_order) { + if (limited) + list = limit_list(list); + + show_commit_list(list); + } else { + if (sort_list_in_merge_order(list, &show_commit)) { + die("merge order sort failed\n"); + } + } + return 0; } diff --git a/t/t6000-rev-list.sh b/t/t6000-rev-list.sh new file mode 100755 --- /dev/null +++ b/t/t6000-rev-list.sh @@ -0,0 +1,116 @@ +#!/bin/sh +# +# Copyright (c) 2005 Jon Seymour +# + +test_description='Test rev-list --merge-order +' +. ./test-lib.sh + +function do_commit +{ + git-commit-tree "$@" /dev/null) + then + echo "^ $next" + else + echo "| $next" + fi + previous=$next + done +} + +function sed_script +{ + for c in root a0 a1 a2 a3 a4 b1 b2 b3 b4 c1 c2 c3 + do + echo -n "s/${!c}/$c/;" + done +} + +date >path0 +git-update-cache --add path0 +tree=$(git-write-tree) +root=$(do_commit $tree) +export GIT_COMMITTER_NAME=foobar # to guarantee that the commit is different +a0=$(do_commit $tree -p $root) +a1=$(do_commit $tree -p $a0) +export GIT_COMMITTER_NAME=foobar2 # to guarantee that the commit is different +b1=$(do_commit $tree -p $root) +c1=$(do_commit $tree -p $b1) +export GIT_COMMITTER_NAME=foobar3 # to guarantee that the commit is different +b2=$(do_commit $tree -p $b1) +b3=$(do_commit $tree -p $b2) +c2=$(do_commit $tree -p $c1 -p $b2) +c3=$(do_commit $tree -p $c2) +a2=$(do_commit $tree -p $a1) +a3=$(do_commit $tree -p $a2) +b4=$(do_commit $tree -p $b3 -p $a3) +a4=$(do_commit $tree -p $a3 -p $b4 -p $c3) +echo $a4 > .git/HEAD + +git-rev-list --merge-order --show-breaks HEAD | sed "$(sed_script)" > actual-merge-order +cat > expected-merge-order < actual-default-order +normal_adjacency_count=$(git-rev-list HEAD | check_adjacency | grep -c "\^" | tr -d ' ') +merge_order_adjacency_count=$(git-rev-list --merge-order HEAD | check_adjacency | grep -c "\^" | tr -d ' ') + +test_expect_success 'Testing that the rev-list has correct number of entries' '[ $(git-rev-list HEAD | wc -l) -eq 13 ]' +test_expect_success 'Testing that --merge-order produces the correct result' 'diff expected-merge-order actual-merge-order' +test_expect_success 'Testing that --merge-order produces as many or fewer discontinuities' '[ $merge_order_adjacency_count -le $normal_adjacency_count ]' + +cat > expected-merge-order-1 < actual-merge-order-1 +test_expect_success 'Testing multiple heads' 'diff expected-merge-order-1 actual-merge-order-1' + +cat > expected-merge-order-2 < actual-merge-order-2 +test_expect_success 'Testing stop' 'diff expected-merge-order-2 actual-merge-order-2' + +test_done