* [PATCH] Modify git-rev-list ... in merge order [ repost with bug fixes ]
@ 2005-06-05 13:47 jon
2005-06-06 0:44 ` Linus Torvalds
0 siblings, 1 reply; 4+ messages in thread
From: jon @ 2005-06-05 13:47 UTC (permalink / raw)
To: git; +Cc: jon.seymour, torvalds
[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 [ note: some bugs in my patch's
support of this functionality have now been fixed ]
For more details about this change, refer to Documentation/git-rev-list.txt
and http://blackcubes.dyndns.org/epoch/.
Signed-off-by: Jon Seymour <jon.seymour@gmail.com>
Diverged from 337cb3fb8da45f10fe9a0c3cf571600f55ead2ce by Linus Torvalds <torvalds@ppc970.osdl.org>
---
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' <commit>
+'git-rev-list' [ *--max-count*=number ] [ *--max-age*=timestamp ] [ *--min-age*=timestamp ] [ *--merge-order* [ *--show-breaks* ] ] <commit>
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 <torvalds@osdl.org>
+Original *--merge-order* logic by Jon Seymour <jon.seymour@gmail.com>
+
Documentation
--------------
Documentation by David Greaves, Junio C Hamano and the git-list <git@vger.kernel.org>.
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 +1,640 @@
+/*
+ * 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 <stdlib.h>
+#include <openssl/bn.h> // 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);
+}
+
+//
+// Finds the base commit of a list of commits.
+//
+// One property of the commit being searched for is that every commit reachable from the base commit is reachable
+// from the commits in the starting list only via paths that include the base commit.
+//
+// This algorithm uses a conservation of mass approach to find the base commit.
+//
+// We start by injecting one unit of mass into the graph at each
+// of the commits in the starting list. Injecting mass into a commit
+// is achieved by adding to its pending mass counter and, if it is not already
+// enqueued, enqueuing the commit in a list of pending commits, in latest commit date
+// first order.
+//
+// The algorithm then preceeds to visit each commit in the pending queue.
+// Upon each visit, the pending mass is added to the mass already seen for that commit and
+// then divided into N equal portions, where N is the number of parents
+// of the commit being visited. The divided portions are then injected into each of
+// the parents.
+//
+// The algorithm continues until we discover a commit which has seen all the
+// mass originally injected or until we run out of things to do.
+//
+// If we find a commit that has seen all the original mass, we have found
+// the common base of all the commits in the starting list.
+//
+// The algorithm does _not_ depend on accurate timestamps for correct operation.
+// However, reasonably sane (e.g. non-random) timestamps are required in order to prevent an exponential
+// performance characteristic. The occasional timestamp inaccuracy will not dramatically
+// affect performance but may result in more nodes being processed than strictly necessary.
+//
+// This procedure sets *boundary to the address of the base commit. It returns non-zero if, and only if,
+// there was a problem parsing one of the commits discovered during the traversal.
+//
+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;
+
+ *boundary = NULL;
+
+ struct fraction injected;
+
+ init_fraction(&injected);
+
+ for (; list; list = list->next) {
+
+ if (list->item->object.util) {
+ fprintf(stderr,
+ "%s:%d:duplicate commit %s discarded.\n",
+ __FILE__,
+ __LINE__,
+ sha1_to_hex(list->item->object.sha1));
+ continue;
+ }
+
+ if (!(list->item->object.flags & UNINTERESTING)) {
+
+ new_mass_counter(list->item, get_one());
+ add(&injected, &injected, get_one());
+
+ commit_list_insert(list->item, &cleaner);
+ commit_list_insert(list->item, &pending);
+ }
+
+ }
+
+ 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;
+ struct commit_list *parents;
+
+ divide(init_fraction(&distribution), &latest_node->pending, num_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);
+
+ insert_by_date(&pending, parent);
+ commit_list_insert(parent, &cleaner);
+
+ } else {
+
+ if (!compare(&parent_node->pending, get_zero())) {
+ insert_by_date(&pending, parent);
+ }
+ add(&parent_node->pending, &parent_node->pending, &distribution);
+
+ }
+ }
+
+ clear_fraction(&distribution);
+
+ }
+
+ if (!compare(&latest_node->seen, &injected)) {
+ *boundary = latest;
+ }
+
+ copy(&latest_node->pending, get_zero());
+
+ }
+
+ while (cleaner) {
+
+ struct commit *next = pop_commit(&cleaner);
+ free_mass_counter((struct mass_counter *) next->object.util);
+ next->object.util = NULL;
+
+ }
+
+ if (pending)
+ free_commit_list(pending);
+
+ clear_fraction(&injected);
+
+ return ret;
+
+}
+
+
+//
+// Finds the base of an minimal, non-linear epoch, headed at head, by
+// applying the find_base_for_list to a list consisting of the head.
+//
+static int find_base(struct commit *head, struct commit **boundary)
+{
+ int ret = 0;
+ struct commit_list *pending = NULL;
+ struct commit_list *next;
+
+ commit_list_insert(head, &pending);
+ for (next = head->parents; next; next = next->next) {
+ commit_list_insert(next->item, &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;
+}
+
+//
+// Pushes an item onto the merge order stack. If the top of the stack is
+// marked as being a possible "break", we check to see whether it actually
+// is a break.
+//
+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 & DISCONTINUITY)) {
+ if (is_parent_of(top->item, item)) {
+ top->item->object.flags &= ~DISCONTINUITY;
+ }
+ }
+ 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 |= VISITED;
+
+ //
+ // 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.
+ //
+
+ while (reversed_parents) {
+
+ struct commit *parent = pop_commit(&reversed_parents);
+
+ if (head->object.flags & UNINTERESTING) {
+ parent->object.flags |= UNINTERESTING;
+ }
+
+ if (!(parent->object.flags & VISITED)) {
+ if (parent->object.flags & BOUNDARY) {
+
+ 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 |= VISITED;
+
+ } 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 |= DISCONTINUITY;
+ }
+ }
+ }
+ }
+
+ push_onto_merge_order_stack(stack, head);
+}
+
+//
+// Emit the contents of the stack.
+//
+// Set a non-zero value if we have seen an uninteresting element while
+// writing out the stack.
+//
+static int emit_stack(struct commit_list ** stack, emitter_func emitter)
+{
+ unsigned int uninteresting = 0;
+ unsigned int seen = 0;
+ int stop = 0;
+
+ while (*stack && !stop) {
+
+ struct commit * next = pop_commit(stack);
+
+ if (next->object.flags & DISCONTINUITY) {
+ // reset the uninteresting flag
+ uninteresting = (next->object.flags & UNINTERESTING);
+ } else {
+ // inherit the uninteresting flag from parent that was on the stack
+ uninteresting |= (next->object.flags & UNINTERESTING);
+ }
+
+ next->object.flags |= uninteresting;
+ seen |= next->object.flags;
+
+ if (*stack) {
+ stop = (*emitter) (next);
+ }
+ }
+
+ if (*stack) {
+ free_commit_list(*stack);
+ *stack = NULL;
+ }
+
+ return stop || (seen & UNINTERESTING);
+}
+
+//
+// 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 = head_of_epoch;
+ int ret = 0;
+ int stop = 0;
+
+ ret = parse_commit(head_of_epoch);
+
+ while (next && next->parents && !ret && !stop) {
+
+ struct commit *base = NULL;
+
+ if ((ret = find_next_epoch_boundary(next, &base)))
+ return ret;
+
+ next->object.flags |= BOUNDARY;
+ if (base) {
+ base->object.flags |= BOUNDARY;
+ }
+
+ if (HAS_EXACTLY_ONE_PARENT(next)) {
+
+ while (HAS_EXACTLY_ONE_PARENT(next) && !stop && !ret) {
+
+ stop = (next->object.flags & UNINTERESTING) || (*emitter) (next);
+ next = next->parents->item;
+ ret = parse_commit(next);
+
+ }
+
+ } else {
+
+ struct commit_list *stack = NULL;
+ sort_first_epoch(next, &stack);
+ stop = emit_stack(&stack, emitter);
+ next = base;
+ }
+
+ }
+
+ if (next && !stop) {
+ stop = (*emitter) (next);
+ }
+
+ return ret;
+}
+
+//
+// Sorts the nodes reachable from a starting list in merge order, we
+// first find the base for the starting list and then sort all nodes in this subgraph
+// using the sort_first_epoch algorithm. Once we have reached the base
+// we can continue sorting using sort_in_merge_order.
+//
+int sort_list_in_merge_order(struct commit_list *list, emitter_func emitter)
+{
+ struct commit_list *stack = NULL;
+ struct commit *base;
+
+ int ret = 0;
+ int stop = 0;
+
+ struct commit_list *reversed = NULL;
+
+ for (; list; list = list->next) {
+ struct commit * next = list->item;
+ if (!(next->object.flags & UNINTERESTING)) {
+ if (next->object.flags & DUPCHECK) {
+ fprintf(stderr, "%s: duplicate commit %s ignored\n", __FUNCTION__, sha1_to_hex(next->object.sha1));
+ } else {
+ next->object.flags |= DUPCHECK;
+ commit_list_insert(list->item, &reversed);
+ }
+ }
+ }
+
+ if (!reversed->next) {
+
+ // if there is only one element in the list, we can sort it using
+ // sort_in_merge_order.
+
+ base = reversed->item;
+
+ } else {
+
+ // otherwise, we search for the base of the list
+
+ if ((ret = find_base_for_list(reversed, &base)))
+ return ret;
+
+ if (base) {
+ base->object.flags |= BOUNDARY;
+ }
+
+ while (reversed) {
+ sort_first_epoch(pop_commit(&reversed), &stack);
+ if (reversed) {
+ //
+ // if we have more parents to push, then the
+ // first push for the next parent may (or may not)
+ // represent a discontinuity with respect to the
+ // parent currently on the top of the stack.
+ //
+ // mark it for checking here, and check it
+ // with the next push...see sort_first_epoch for
+ // more details.
+ //
+ stack->item->object.flags |= DISCONTINUITY;
+ }
+ }
+
+ stop = emit_stack(&stack, emitter);
+ }
+
+ if (!stop && base) {
+ 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 +1,14 @@
+#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 BOUNDARY (1u<<3)
+#define VISITED (1u<<4)
+#define DISCONTINUITY (1u<<5)
+#define DUPCHECK (1u<<6)
+
+#endif /* EPOCH_H */
diff --git a/git-resolve-script b/git-resolve-script
old mode 100644
new mode 100755
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 <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 &DISCONTINUITY) {
+ c = '^';
+ } else if (commit->object.flags & BOUNDARY) {
+ 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 +1,173 @@
+#!/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
+}
+
+function check_adjacency
+{
+ read previous
+ echo "= $previous"
+ while read next
+ do
+ if ! (git-cat-file commit $previous | grep "^parent $next" >/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 l0 l1 l2 l3 l4 l5
+ do
+ echo -n "s/${!c}/$c/;"
+ done
+}
+
+date >path0
+git-update-cache --add path0
+tree=$(git-write-tree)
+root=$(do_commit $tree 2>/dev/null)
+export GIT_COMMITTER_NAME=foobar # to guarantee that the commit is different
+l0=$(do_commit $tree -p $root)
+l1=$(do_commit $tree -p $l0)
+l2=$(do_commit $tree -p $l1)
+a0=$(do_commit $tree -p $l2)
+a1=$(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 $c3)
+l3=$(do_commit $tree -p $a4)
+l4=$(do_commit $tree -p $l3)
+l5=$(do_commit $tree -p $l4)
+echo $l5 > .git/HEAD
+
+git-rev-list --merge-order --show-breaks HEAD | sed "$(sed_script)" > actual-merge-order
+cat > expected-merge-order <<EOF
+= l5
+| l4
+| l3
+= a4
+| c3
+| c2
+| c1
+^ b4
+| b3
+| b2
+| b1
+^ a3
+| a2
+| a1
+| a0
+| l2
+| l1
+| l0
+= root
+EOF
+
+git-rev-list HEAD | check_adjacency | sed "$(sed_script)" > actual-default-order
+normal_adjacency_count=$(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 19 ]'
+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 <<EOF
+c3
+c2
+c1
+b3
+b2
+b1
+a3
+a2
+a1
+a0
+l2
+l1
+l0
+root
+EOF
+
+git-rev-list --merge-order $a3 $b3 $c3 | sed "$(sed_script)" > actual-merge-order-1
+test_expect_success 'Testing multiple heads' 'diff expected-merge-order-1 actual-merge-order-1'
+
+cat > expected-merge-order-2 <<EOF
+c3
+c2
+c1
+b3
+b2
+b1
+a3
+a2
+EOF
+
+git-rev-list --merge-order $a3 $b3 $c3 ^$a1 | sed "$(sed_script)" > actual-merge-order-2
+test_expect_success 'Testing stop' 'diff expected-merge-order-2 actual-merge-order-2'
+
+cat > expected-merge-order-3 <<EOF
+c3
+c2
+c1
+b3
+b2
+b1
+a3
+a2
+a1
+a0
+l2
+EOF
+
+git-rev-list --merge-order $a3 $b3 $c3 ^$l1 | sed "$(sed_script)" > actual-merge-order-3
+test_expect_success 'Testing stop in linear epoch' 'diff expected-merge-order-3 actual-merge-order-3'
+
+cat > expected-merge-order-4 <<EOF
+l5
+l4
+l3
+a4
+c3
+c2
+c1
+b4
+b3
+b2
+b1
+a3
+a2
+a1
+a0
+l2
+EOF
+
+git-rev-list --merge-order $l5 ^$l1 | sed "$(sed_script)" > actual-merge-order-4
+test_expect_success 'Testing start in linear epoch, stop after non-linear epoch' 'diff expected-merge-order-4 actual-merge-order-4'
+
+git-rev-list --merge-order $l5 $l5 ^$l1 2>/dev/null | sed "$(sed_script)" > actual-merge-order-5
+test_expect_success 'Testing duplicated start arguments' 'diff expected-merge-order-4 actual-merge-order-5'
+
+test_done
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [PATCH] Modify git-rev-list ... in merge order [ repost with bug fixes ]
2005-06-05 13:47 [PATCH] Modify git-rev-list ... in merge order [ repost with bug fixes ] jon
@ 2005-06-06 0:44 ` Linus Torvalds
2005-06-06 1:09 ` Jon Seymour
0 siblings, 1 reply; 4+ messages in thread
From: Linus Torvalds @ 2005-06-06 0:44 UTC (permalink / raw)
To: jon; +Cc: git, jon.seymour
On Sun, 5 Jun 2005 jon@blackcubes.dyndns.org wrote:
>
> -static void show_commit(struct commit *commit)
> +static int show_commit(struct commit *commit)
Ick. You've mixed "show_commit()" to be three totally independent things
- deciding whether to show at all
- showing the commit in traditional format
- showing the commit tree in the new "break" format
I really hate functions that do totally unrelated things, and I'm so much
happier with the new show_commit() than the old "everything in one big
function" thing, that I'm unhappy about mixing the thing up again.
Please leave show_commit() to just show the commit, and make the other
decisions be independent of that.
Linus
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [PATCH] Modify git-rev-list ... in merge order [ repost with bug fixes ]
2005-06-06 0:44 ` Linus Torvalds
@ 2005-06-06 1:09 ` Jon Seymour
2005-06-06 1:43 ` Linus Torvalds
0 siblings, 1 reply; 4+ messages in thread
From: Jon Seymour @ 2005-06-06 1:09 UTC (permalink / raw)
To: Linus Torvalds; +Cc: git
On 6/6/05, Linus Torvalds <torvalds@osdl.org> wrote:
>
>
> On Sun, 5 Jun 2005 jon@blackcubes.dyndns.org wrote:
> >
> > -static void show_commit(struct commit *commit)
> > +static int show_commit(struct commit *commit)
>
> Ick. You've mixed "show_commit()" to be three totally independent things
> - deciding whether to show at all
> - showing the commit in traditional format
> - showing the commit tree in the new "break" format
>
> I really hate functions that do totally unrelated things, and I'm so much
> happier with the new show_commit() than the old "everything in one big
> function" thing, that I'm unhappy about mixing the thing up again.
>
> Please leave show_commit() to just show the commit, and make the other
> decisions be independent of that.
My rationale was to re-use both the filtering logic currently in the
show_commit_list while loop and the display logic, since I need both
in order to maximise compatibility with the standard algorithm.
However, I understand your concerns.
My plan, therefore, is to split the filtering logic from
show_commit_list's while loop into a separate function and create a
third function which calls the filtering logic, then show_commit. I'll
pass a pointer to the third function to sort_list_in_merge_order. I
can leave the show_breaks functionality in show_commit (it is, after
all, display functionality) or I can move it into the third function.
Is that ok by you?
jon.
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [PATCH] Modify git-rev-list ... in merge order [ repost with bug fixes ]
2005-06-06 1:09 ` Jon Seymour
@ 2005-06-06 1:43 ` Linus Torvalds
0 siblings, 0 replies; 4+ messages in thread
From: Linus Torvalds @ 2005-06-06 1:43 UTC (permalink / raw)
To: jon; +Cc: git
On Mon, 6 Jun 2005, Jon Seymour wrote:
>
> My rationale was to re-use both the filtering logic currently in the
> show_commit_list while loop and the display logic, since I need both
> in order to maximise compatibility with the standard algorithm.
It's obviously ok to re-use the filtering, I'm just objecting to putting
it into a function that is really unrelated to filtering..
> My plan, therefore, is to split the filtering logic from
> show_commit_list's while loop into a separate function and create a
> third function which calls the filtering logic, then show_commit.
Yes.
Linus
^ permalink raw reply [flat|nested] 4+ messages in thread
end of thread, other threads:[~2005-06-06 1:38 UTC | newest]
Thread overview: 4+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2005-06-05 13:47 [PATCH] Modify git-rev-list ... in merge order [ repost with bug fixes ] jon
2005-06-06 0:44 ` Linus Torvalds
2005-06-06 1:09 ` Jon Seymour
2005-06-06 1:43 ` Linus Torvalds
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