#include "diffcore.h"
#include "tree.h"
+/*
+ * internal mode marker, saying a tree entry != entry of tp[imin]
+ * (see ll_diff_tree_paths for what it means there)
+ *
+ * we will update/use/emit entry for diff only with it unset.
+ */
+#define S_IFXMIN_NEQ S_DIFFTREE_IFXMIN_NEQ
+
+static struct combine_diff_path *ll_diff_tree_paths(
+ struct combine_diff_path *p, const unsigned char *sha1,
+ const unsigned char **parents_sha1, int nparent,
+ struct strbuf *base, struct diff_options *opt);
static int ll_diff_tree_sha1(const unsigned char *old, const unsigned char *new,
struct strbuf *base, struct diff_options *opt);
}
-/* convert path, t1/t2 -> opt->diff_*() callbacks */
-static void emit_diff(struct diff_options *opt, struct strbuf *path,
- struct tree_desc *t1, struct tree_desc *t2)
+/*
+ * convert path -> opt->diff_*() callbacks
+ *
+ * emits diff to first parent only, and tells diff tree-walker that we are done
+ * with p and it can be freed.
+ */
+static int emit_diff_first_parent_only(struct diff_options *opt, struct combine_diff_path *p)
{
- unsigned int mode1 = t1 ? t1->entry.mode : 0;
- unsigned int mode2 = t2 ? t2->entry.mode : 0;
-
- if (mode1 && mode2) {
- opt->change(opt, mode1, mode2, t1->entry.sha1, t2->entry.sha1,
- 1, 1, path->buf, 0, 0);
+ struct combine_diff_parent *p0 = &p->parent[0];
+ if (p->mode && p0->mode) {
+ opt->change(opt, p0->mode, p->mode, p0->sha1, p->sha1,
+ 1, 1, p->path, 0, 0);
}
else {
const unsigned char *sha1;
unsigned int mode;
int addremove;
- if (mode2) {
+ if (p->mode) {
addremove = '+';
- sha1 = t2->entry.sha1;
- mode = mode2;
+ sha1 = p->sha1;
+ mode = p->mode;
} else {
addremove = '-';
- sha1 = t1->entry.sha1;
- mode = mode1;
+ sha1 = p0->sha1;
+ mode = p0->mode;
}
- opt->add_remove(opt, addremove, mode, sha1, 1, path->buf, 0);
+ opt->add_remove(opt, addremove, mode, sha1, 1, p->path, 0);
}
+
+ return 0; /* we are done with p */
}
-/* new path should be added to diff
+/*
+ * Make a new combine_diff_path from path/mode/sha1
+ * and append it to paths list tail.
+ *
+ * Memory for created elements could be reused:
+ *
+ * - if last->next == NULL, the memory is allocated;
+ *
+ * - if last->next != NULL, it is assumed that p=last->next was returned
+ * earlier by this function, and p->next was *not* modified.
+ * The memory is then reused from p.
+ *
+ * so for clients,
+ *
+ * - if you do need to keep the element
+ *
+ * p = path_appendnew(p, ...);
+ * process(p);
+ * p->next = NULL;
+ *
+ * - if you don't need to keep the element after processing
+ *
+ * pprev = p;
+ * p = path_appendnew(p, ...);
+ * process(p);
+ * p = pprev;
+ * ; don't forget to free tail->next in the end
+ *
+ * p->parent[] remains uninitialized.
+ */
+static struct combine_diff_path *path_appendnew(struct combine_diff_path *last,
+ int nparent, const struct strbuf *base, const char *path, int pathlen,
+ unsigned mode, const unsigned char *sha1)
+{
+ struct combine_diff_path *p;
+ int len = base->len + pathlen;
+ int alloclen = combine_diff_path_size(nparent, len);
+
+ /* if last->next is !NULL - it is a pre-allocated memory, we can reuse */
+ p = last->next;
+ if (p && (alloclen > (intptr_t)p->next)) {
+ free(p);
+ p = NULL;
+ }
+
+ if (!p) {
+ p = xmalloc(alloclen);
+
+ /*
+ * until we go to it next round, .next holds how many bytes we
+ * allocated (for faster realloc - we don't need copying old data).
+ */
+ p->next = (struct combine_diff_path *)(intptr_t)alloclen;
+ }
+
+ last->next = p;
+
+ p->path = (char *)&(p->parent[nparent]);
+ memcpy(p->path, base->buf, base->len);
+ memcpy(p->path + base->len, path, pathlen);
+ p->path[len] = 0;
+ p->mode = mode;
+ hashcpy(p->sha1, sha1 ? sha1 : null_sha1);
+
+ return p;
+}
+
+/*
+ * new path should be added to combine diff
*
* 3 cases on how/when it should be called and behaves:
*
- * !t1, t2 -> path added, parent lacks it
- * t1, !t2 -> path removed from parent
- * t1, t2 -> path modified
+ * t, !tp -> path added, all parents lack it
+ * !t, tp -> path removed from all parents
+ * t, tp -> path modified/added
+ * (M for tp[i]=tp[imin], A otherwise)
*/
-static void show_path(struct strbuf *base, struct diff_options *opt,
- struct tree_desc *t1, struct tree_desc *t2)
+static struct combine_diff_path *emit_path(struct combine_diff_path *p,
+ struct strbuf *base, struct diff_options *opt, int nparent,
+ struct tree_desc *t, struct tree_desc *tp,
+ int imin)
{
unsigned mode;
const char *path;
+ const unsigned char *sha1;
int pathlen;
int old_baselen = base->len;
- int isdir, recurse = 0, emitthis = 1;
+ int i, isdir, recurse = 0, emitthis = 1;
/* at least something has to be valid */
- assert(t1 || t2);
+ assert(t || tp);
- if (t2) {
+ if (t) {
/* path present in resulting tree */
- tree_entry_extract(t2, &path, &mode);
- pathlen = tree_entry_len(&t2->entry);
+ sha1 = tree_entry_extract(t, &path, &mode);
+ pathlen = tree_entry_len(&t->entry);
isdir = S_ISDIR(mode);
} else {
/*
- * a path was removed - take path from parent. Also take
- * mode from parent, to decide on recursion.
+ * a path was removed - take path from imin parent. Also take
+ * mode from that parent, to decide on recursion(1).
+ *
+ * 1) all modes for tp[i]=tp[imin] should be the same wrt
+ * S_ISDIR, thanks to base_name_compare().
*/
- tree_entry_extract(t1, &path, &mode);
- pathlen = tree_entry_len(&t1->entry);
+ tree_entry_extract(&tp[imin], &path, &mode);
+ pathlen = tree_entry_len(&tp[imin].entry);
isdir = S_ISDIR(mode);
+ sha1 = NULL;
mode = 0;
}
emitthis = DIFF_OPT_TST(opt, TREE_IN_RECURSIVE);
}
- strbuf_add(base, path, pathlen);
+ if (emitthis) {
+ int keep;
+ struct combine_diff_path *pprev = p;
+ p = path_appendnew(p, nparent, base, path, pathlen, mode, sha1);
+
+ for (i = 0; i < nparent; ++i) {
+ /*
+ * tp[i] is valid, if present and if tp[i]==tp[imin] -
+ * otherwise, we should ignore it.
+ */
+ int tpi_valid = tp && !(tp[i].entry.mode & S_IFXMIN_NEQ);
+
+ const unsigned char *sha1_i;
+ unsigned mode_i;
+
+ p->parent[i].status =
+ !t ? DIFF_STATUS_DELETED :
+ tpi_valid ?
+ DIFF_STATUS_MODIFIED :
+ DIFF_STATUS_ADDED;
+
+ if (tpi_valid) {
+ sha1_i = tp[i].entry.sha1;
+ mode_i = tp[i].entry.mode;
+ }
+ else {
+ sha1_i = NULL;
+ mode_i = 0;
+ }
+
+ p->parent[i].mode = mode_i;
+ hashcpy(p->parent[i].sha1, sha1_i ? sha1_i : null_sha1);
+ }
- if (emitthis)
- emit_diff(opt, base, t1, t2);
+ keep = 1;
+ if (opt->pathchange)
+ keep = opt->pathchange(opt, p);
+
+ /*
+ * If a path was filtered or consumed - we don't need to add it
+ * to the list and can reuse its memory, leaving it as
+ * pre-allocated element on the tail.
+ *
+ * On the other hand, if path needs to be kept, we need to
+ * correct its .next to NULL, as it was pre-initialized to how
+ * much memory was allocated.
+ *
+ * see path_appendnew() for details.
+ */
+ if (!keep)
+ p = pprev;
+ else
+ p->next = NULL;
+ }
if (recurse) {
+ const unsigned char **parents_sha1;
+
+ parents_sha1 = xalloca(nparent * sizeof(parents_sha1[0]));
+ for (i = 0; i < nparent; ++i) {
+ /* same rule as in emitthis */
+ int tpi_valid = tp && !(tp[i].entry.mode & S_IFXMIN_NEQ);
+
+ parents_sha1[i] = tpi_valid ? tp[i].entry.sha1
+ : NULL;
+ }
+
+ strbuf_add(base, path, pathlen);
strbuf_addch(base, '/');
- ll_diff_tree_sha1(t1 ? t1->entry.sha1 : NULL,
- t2 ? t2->entry.sha1 : NULL, base, opt);
+ p = ll_diff_tree_paths(p, sha1, parents_sha1, nparent, base, opt);
+ xalloca_free(parents_sha1);
}
strbuf_setlen(base, old_baselen);
+ return p;
}
static void skip_uninteresting(struct tree_desc *t, struct strbuf *base,
}
}
-static int ll_diff_tree_sha1(const unsigned char *old, const unsigned char *new,
- struct strbuf *base, struct diff_options *opt)
+
+/*
+ * generate paths for combined diff D(sha1,parents_sha1[])
+ *
+ * Resulting paths are appended to combine_diff_path linked list, and also, are
+ * emitted on the go via opt->pathchange() callback, so it is possible to
+ * process the result as batch or incrementally.
+ *
+ * The paths are generated scanning new tree and all parents trees
+ * simultaneously, similarly to what diff_tree() was doing for 2 trees.
+ * The theory behind such scan is as follows:
+ *
+ *
+ * D(T,P1...Pn) calculation scheme
+ * -------------------------------
+ *
+ * D(T,P1...Pn) = D(T,P1) ^ ... ^ D(T,Pn) (regarding resulting paths set)
+ *
+ * D(T,Pj) - diff between T..Pj
+ * D(T,P1...Pn) - combined diff from T to parents P1,...,Pn
+ *
+ *
+ * We start from all trees, which are sorted, and compare their entries in
+ * lock-step:
+ *
+ * T P1 Pn
+ * - - -
+ * |t| |p1| |pn|
+ * |-| |--| ... |--| imin = argmin(p1...pn)
+ * | | | | | |
+ * |-| |--| |--|
+ * |.| |. | |. |
+ * . . .
+ * . . .
+ *
+ * at any time there could be 3 cases:
+ *
+ * 1) t < p[imin];
+ * 2) t > p[imin];
+ * 3) t = p[imin].
+ *
+ * Schematic deduction of what every case means, and what to do, follows:
+ *
+ * 1) t < p[imin] -> ∀j t ∉ Pj -> "+t" ∈ D(T,Pj) -> D += "+t"; t↓
+ *
+ * 2) t > p[imin]
+ *
+ * 2.1) ∃j: pj > p[imin] -> "-p[imin]" ∉ D(T,Pj) -> D += ø; ∀ pi=p[imin] pi↓
+ * 2.2) ∀i pi = p[imin] -> pi ∉ T -> "-pi" ∈ D(T,Pi) -> D += "-p[imin]"; ∀i pi↓
+ *
+ * 3) t = p[imin]
+ *
+ * 3.1) ∃j: pj > p[imin] -> "+t" ∈ D(T,Pj) -> only pi=p[imin] remains to investigate
+ * 3.2) pi = p[imin] -> investigate δ(t,pi)
+ * |
+ * |
+ * v
+ *
+ * 3.1+3.2) looking at δ(t,pi) ∀i: pi=p[imin] - if all != ø ->
+ *
+ * ⎧δ(t,pi) - if pi=p[imin]
+ * -> D += ⎨
+ * ⎩"+t" - if pi>p[imin]
+ *
+ *
+ * in any case t↓ ∀ pi=p[imin] pi↓
+ *
+ *
+ * ~~~~~~~~
+ *
+ * NOTE
+ *
+ * Usual diff D(A,B) is by definition the same as combined diff D(A,[B]),
+ * so this diff paths generator can, and is used, for plain diffs
+ * generation too.
+ *
+ * Please keep attention to the common D(A,[B]) case when working on the
+ * code, in order not to slow it down.
+ *
+ * NOTE
+ * nparent must be > 0.
+ */
+
+
+/* ∀ pi=p[imin] pi↓ */
+static inline void update_tp_entries(struct tree_desc *tp, int nparent)
{
- struct tree_desc t1, t2;
- void *t1tree, *t2tree;
+ int i;
+ for (i = 0; i < nparent; ++i)
+ if (!(tp[i].entry.mode & S_IFXMIN_NEQ))
+ update_tree_entry(&tp[i]);
+}
- t1tree = fill_tree_descriptor(&t1, old);
- t2tree = fill_tree_descriptor(&t2, new);
+static struct combine_diff_path *ll_diff_tree_paths(
+ struct combine_diff_path *p, const unsigned char *sha1,
+ const unsigned char **parents_sha1, int nparent,
+ struct strbuf *base, struct diff_options *opt)
+{
+ struct tree_desc t, *tp;
+ void *ttree, **tptree;
+ int i;
+
+ tp = xalloca(nparent * sizeof(tp[0]));
+ tptree = xalloca(nparent * sizeof(tptree[0]));
+
+ /*
+ * load parents first, as they are probably already cached.
+ *
+ * ( log_tree_diff() parses commit->parent before calling here via
+ * diff_tree_sha1(parent, commit) )
+ */
+ for (i = 0; i < nparent; ++i)
+ tptree[i] = fill_tree_descriptor(&tp[i], parents_sha1[i]);
+ ttree = fill_tree_descriptor(&t, sha1);
/* Enable recursion indefinitely */
opt->pathspec.recursive = DIFF_OPT_TST(opt, RECURSIVE);
for (;;) {
- int cmp;
+ int imin, cmp;
if (diff_can_quit_early(opt))
break;
+
if (opt->pathspec.nr) {
- skip_uninteresting(&t1, base, opt);
- skip_uninteresting(&t2, base, opt);
+ skip_uninteresting(&t, base, opt);
+ for (i = 0; i < nparent; i++)
+ skip_uninteresting(&tp[i], base, opt);
+ }
+
+ /* comparing is finished when all trees are done */
+ if (!t.size) {
+ int done = 1;
+ for (i = 0; i < nparent; ++i)
+ if (tp[i].size) {
+ done = 0;
+ break;
+ }
+ if (done)
+ break;
+ }
+
+ /*
+ * lookup imin = argmin(p1...pn),
+ * mark entries whether they =p[imin] along the way
+ */
+ imin = 0;
+ tp[0].entry.mode &= ~S_IFXMIN_NEQ;
+
+ for (i = 1; i < nparent; ++i) {
+ cmp = tree_entry_pathcmp(&tp[i], &tp[imin]);
+ if (cmp < 0) {
+ imin = i;
+ tp[i].entry.mode &= ~S_IFXMIN_NEQ;
+ }
+ else if (cmp == 0) {
+ tp[i].entry.mode &= ~S_IFXMIN_NEQ;
+ }
+ else {
+ tp[i].entry.mode |= S_IFXMIN_NEQ;
+ }
}
- if (!t1.size && !t2.size)
- break;
- cmp = tree_entry_pathcmp(&t1, &t2);
+ /* fixup markings for entries before imin */
+ for (i = 0; i < imin; ++i)
+ tp[i].entry.mode |= S_IFXMIN_NEQ; /* pi > p[imin] */
- /* t1 = t2 */
- if (cmp == 0) {
- if (DIFF_OPT_TST(opt, FIND_COPIES_HARDER) ||
- hashcmp(t1.entry.sha1, t2.entry.sha1) ||
- (t1.entry.mode != t2.entry.mode))
- show_path(base, opt, &t1, &t2);
- update_tree_entry(&t1);
- update_tree_entry(&t2);
+
+ /* compare t vs p[imin] */
+ cmp = tree_entry_pathcmp(&t, &tp[imin]);
+
+ /* t = p[imin] */
+ if (cmp == 0) {
+ /* are either pi > p[imin] or diff(t,pi) != ø ? */
+ if (!DIFF_OPT_TST(opt, FIND_COPIES_HARDER)) {
+ for (i = 0; i < nparent; ++i) {
+ /* p[i] > p[imin] */
+ if (tp[i].entry.mode & S_IFXMIN_NEQ)
+ continue;
+
+ /* diff(t,pi) != ø */
+ if (hashcmp(t.entry.sha1, tp[i].entry.sha1) ||
+ (t.entry.mode != tp[i].entry.mode))
+ continue;
+
+ goto skip_emit_t_tp;
+ }
+ }
+
+ /* D += {δ(t,pi) if pi=p[imin]; "+a" if pi > p[imin]} */
+ p = emit_path(p, base, opt, nparent,
+ &t, tp, imin);
+
+ skip_emit_t_tp:
+ /* t↓, ∀ pi=p[imin] pi↓ */
+ update_tree_entry(&t);
+ update_tp_entries(tp, nparent);
}
- /* t1 < t2 */
+ /* t < p[imin] */
else if (cmp < 0) {
- show_path(base, opt, &t1, /*t2=*/NULL);
- update_tree_entry(&t1);
+ /* D += "+t" */
+ p = emit_path(p, base, opt, nparent,
+ &t, /*tp=*/NULL, -1);
+
+ /* t↓ */
+ update_tree_entry(&t);
}
- /* t1 > t2 */
+ /* t > p[imin] */
else {
- show_path(base, opt, /*t1=*/NULL, &t2);
- update_tree_entry(&t2);
+ /* ∀i pi=p[imin] -> D += "-p[imin]" */
+ if (!DIFF_OPT_TST(opt, FIND_COPIES_HARDER)) {
+ for (i = 0; i < nparent; ++i)
+ if (tp[i].entry.mode & S_IFXMIN_NEQ)
+ goto skip_emit_tp;
+ }
+
+ p = emit_path(p, base, opt, nparent,
+ /*t=*/NULL, tp, imin);
+
+ skip_emit_tp:
+ /* ∀ pi=p[imin] pi↓ */
+ update_tp_entries(tp, nparent);
}
}
- free(t2tree);
- free(t1tree);
- return 0;
+ free(ttree);
+ for (i = nparent-1; i >= 0; i--)
+ free(tptree[i]);
+ xalloca_free(tptree);
+ xalloca_free(tp);
+
+ return p;
+}
+
+struct combine_diff_path *diff_tree_paths(
+ struct combine_diff_path *p, const unsigned char *sha1,
+ const unsigned char **parents_sha1, int nparent,
+ struct strbuf *base, struct diff_options *opt)
+{
+ p = ll_diff_tree_paths(p, sha1, parents_sha1, nparent, base, opt);
+
+ /*
+ * free pre-allocated last element, if any
+ * (see path_appendnew() for details about why)
+ */
+ if (p->next) {
+ free(p->next);
+ p->next = NULL;
+ }
+
+ return p;
}
/*
q->nr = 1;
}
+static int ll_diff_tree_sha1(const unsigned char *old, const unsigned char *new,
+ struct strbuf *base, struct diff_options *opt)
+{
+ struct combine_diff_path phead, *p;
+ pathchange_fn_t pathchange_old = opt->pathchange;
+
+ phead.next = NULL;
+ opt->pathchange = emit_diff_first_parent_only;
+ diff_tree_paths(&phead, new, &old, 1, base, opt);
+
+ for (p = phead.next; p;) {
+ struct combine_diff_path *pprev = p;
+ p = p->next;
+ free(pprev);
+ }
+
+ opt->pathchange = pathchange_old;
+ return 0;
+}
+
int diff_tree_sha1(const unsigned char *old, const unsigned char *new, const char *base_str, struct diff_options *opt)
{
struct strbuf base;