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-rw-r--r--xdiff/xmerge.c587
1 files changed, 587 insertions, 0 deletions
diff --git a/xdiff/xmerge.c b/xdiff/xmerge.c
new file mode 100644
index 000000000..d9737f04c
--- /dev/null
+++ b/xdiff/xmerge.c
@@ -0,0 +1,587 @@
+/*
+ * LibXDiff by Davide Libenzi ( File Differential Library )
+ * Copyright (C) 2003-2006 Davide Libenzi, Johannes E. Schindelin
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
+ *
+ * Davide Libenzi <davidel@xmailserver.org>
+ *
+ */
+
+#include "xinclude.h"
+
+typedef struct s_xdmerge {
+ struct s_xdmerge *next;
+ /*
+ * 0 = conflict,
+ * 1 = no conflict, take first,
+ * 2 = no conflict, take second.
+ */
+ int mode;
+ /*
+ * These point at the respective postimages. E.g. <i1,chg1> is
+ * how side #1 wants to change the common ancestor; if there is no
+ * overlap, lines before i1 in the postimage of side #1 appear
+ * in the merge result as a region touched by neither side.
+ */
+ long i1, i2;
+ long chg1, chg2;
+ /*
+ * These point at the preimage; of course there is just one
+ * preimage, that is from the shared common ancestor.
+ */
+ long i0;
+ long chg0;
+} xdmerge_t;
+
+static int xdl_append_merge(xdmerge_t **merge, int mode,
+ long i0, long chg0,
+ long i1, long chg1,
+ long i2, long chg2)
+{
+ xdmerge_t *m = *merge;
+ if (m && (i1 <= m->i1 + m->chg1 || i2 <= m->i2 + m->chg2)) {
+ if (mode != m->mode)
+ m->mode = 0;
+ m->chg0 = i0 + chg0 - m->i0;
+ m->chg1 = i1 + chg1 - m->i1;
+ m->chg2 = i2 + chg2 - m->i2;
+ } else {
+ m = xdl_malloc(sizeof(xdmerge_t));
+ if (!m)
+ return -1;
+ m->next = NULL;
+ m->mode = mode;
+ m->i0 = i0;
+ m->chg0 = chg0;
+ m->i1 = i1;
+ m->chg1 = chg1;
+ m->i2 = i2;
+ m->chg2 = chg2;
+ if (*merge)
+ (*merge)->next = m;
+ *merge = m;
+ }
+ return 0;
+}
+
+static int xdl_cleanup_merge(xdmerge_t *c)
+{
+ int count = 0;
+ xdmerge_t *next_c;
+
+ /* were there conflicts? */
+ for (; c; c = next_c) {
+ if (c->mode == 0)
+ count++;
+ next_c = c->next;
+ free(c);
+ }
+ return count;
+}
+
+static int xdl_merge_cmp_lines(xdfenv_t *xe1, int i1, xdfenv_t *xe2, int i2,
+ int line_count, long flags)
+{
+ int i;
+ xrecord_t **rec1 = xe1->xdf2.recs + i1;
+ xrecord_t **rec2 = xe2->xdf2.recs + i2;
+
+ for (i = 0; i < line_count; i++) {
+ int result = xdl_recmatch(rec1[i]->ptr, rec1[i]->size,
+ rec2[i]->ptr, rec2[i]->size, flags);
+ if (!result)
+ return -1;
+ }
+ return 0;
+}
+
+static int xdl_recs_copy_0(int use_orig, xdfenv_t *xe, int i, int count, int add_nl, char *dest)
+{
+ xrecord_t **recs;
+ int size = 0;
+
+ recs = (use_orig ? xe->xdf1.recs : xe->xdf2.recs) + i;
+
+ if (count < 1)
+ return 0;
+
+ for (i = 0; i < count; size += recs[i++]->size)
+ if (dest)
+ memcpy(dest + size, recs[i]->ptr, recs[i]->size);
+ if (add_nl) {
+ i = recs[count - 1]->size;
+ if (i == 0 || recs[count - 1]->ptr[i - 1] != '\n') {
+ if (dest)
+ dest[size] = '\n';
+ size++;
+ }
+ }
+ return size;
+}
+
+static int xdl_recs_copy(xdfenv_t *xe, int i, int count, int add_nl, char *dest)
+{
+ return xdl_recs_copy_0(0, xe, i, count, add_nl, dest);
+}
+
+static int xdl_orig_copy(xdfenv_t *xe, int i, int count, int add_nl, char *dest)
+{
+ return xdl_recs_copy_0(1, xe, i, count, add_nl, dest);
+}
+
+static int fill_conflict_hunk(xdfenv_t *xe1, const char *name1,
+ xdfenv_t *xe2, const char *name2,
+ int size, int i, int style,
+ xdmerge_t *m, char *dest)
+{
+ const int marker_size = 7;
+ int marker1_size = (name1 ? strlen(name1) + 1 : 0);
+ int marker2_size = (name2 ? strlen(name2) + 1 : 0);
+ int j;
+
+ /* Before conflicting part */
+ size += xdl_recs_copy(xe1, i, m->i1 - i, 0,
+ dest ? dest + size : NULL);
+
+ if (!dest) {
+ size += marker_size + 1 + marker1_size;
+ } else {
+ for (j = 0; j < marker_size; j++)
+ dest[size++] = '<';
+ if (marker1_size) {
+ dest[size] = ' ';
+ memcpy(dest + size + 1, name1, marker1_size - 1);
+ size += marker1_size;
+ }
+ dest[size++] = '\n';
+ }
+
+ /* Postimage from side #1 */
+ size += xdl_recs_copy(xe1, m->i1, m->chg1, 1,
+ dest ? dest + size : NULL);
+
+ if (style == XDL_MERGE_DIFF3) {
+ /* Shared preimage */
+ if (!dest) {
+ size += marker_size + 1;
+ } else {
+ for (j = 0; j < marker_size; j++)
+ dest[size++] = '|';
+ dest[size++] = '\n';
+ }
+ size += xdl_orig_copy(xe1, m->i0, m->chg0, 1,
+ dest ? dest + size : NULL);
+ }
+
+ if (!dest) {
+ size += marker_size + 1;
+ } else {
+ for (j = 0; j < marker_size; j++)
+ dest[size++] = '=';
+ dest[size++] = '\n';
+ }
+
+ /* Postimage from side #2 */
+ size += xdl_recs_copy(xe2, m->i2, m->chg2, 1,
+ dest ? dest + size : NULL);
+ if (!dest) {
+ size += marker_size + 1 + marker2_size;
+ } else {
+ for (j = 0; j < marker_size; j++)
+ dest[size++] = '>';
+ if (marker2_size) {
+ dest[size] = ' ';
+ memcpy(dest + size + 1, name2, marker2_size - 1);
+ size += marker2_size;
+ }
+ dest[size++] = '\n';
+ }
+ return size;
+}
+
+static int xdl_fill_merge_buffer(xdfenv_t *xe1, const char *name1,
+ xdfenv_t *xe2, const char *name2,
+ xdmerge_t *m, char *dest, int style)
+{
+ int size, i;
+
+ for (size = i = 0; m; m = m->next) {
+ if (m->mode == 0)
+ size = fill_conflict_hunk(xe1, name1, xe2, name2,
+ size, i, style, m, dest);
+ else if (m->mode == 1)
+ size += xdl_recs_copy(xe1, i, m->i1 + m->chg1 - i, 0,
+ dest ? dest + size : NULL);
+ else if (m->mode == 2)
+ size += xdl_recs_copy(xe2, m->i2 - m->i1 + i,
+ m->i1 + m->chg2 - i, 0,
+ dest ? dest + size : NULL);
+ else
+ continue;
+ i = m->i1 + m->chg1;
+ }
+ size += xdl_recs_copy(xe1, i, xe1->xdf2.nrec - i, 0,
+ dest ? dest + size : NULL);
+ return size;
+}
+
+/*
+ * Sometimes, changes are not quite identical, but differ in only a few
+ * lines. Try hard to show only these few lines as conflicting.
+ */
+static int xdl_refine_conflicts(xdfenv_t *xe1, xdfenv_t *xe2, xdmerge_t *m,
+ xpparam_t const *xpp)
+{
+ for (; m; m = m->next) {
+ mmfile_t t1, t2;
+ xdfenv_t xe;
+ xdchange_t *xscr, *x;
+ int i1 = m->i1, i2 = m->i2;
+
+ /* let's handle just the conflicts */
+ if (m->mode)
+ continue;
+
+ /* no sense refining a conflict when one side is empty */
+ if (m->chg1 == 0 || m->chg2 == 0)
+ continue;
+
+ /*
+ * This probably does not work outside git, since
+ * we have a very simple mmfile structure.
+ */
+ t1.ptr = (char *)xe1->xdf2.recs[m->i1]->ptr;
+ t1.size = xe1->xdf2.recs[m->i1 + m->chg1 - 1]->ptr
+ + xe1->xdf2.recs[m->i1 + m->chg1 - 1]->size - t1.ptr;
+ t2.ptr = (char *)xe2->xdf2.recs[m->i2]->ptr;
+ t2.size = xe2->xdf2.recs[m->i2 + m->chg2 - 1]->ptr
+ + xe2->xdf2.recs[m->i2 + m->chg2 - 1]->size - t2.ptr;
+ if (xdl_do_diff(&t1, &t2, xpp, &xe) < 0)
+ return -1;
+ if (xdl_change_compact(&xe.xdf1, &xe.xdf2, xpp->flags) < 0 ||
+ xdl_change_compact(&xe.xdf2, &xe.xdf1, xpp->flags) < 0 ||
+ xdl_build_script(&xe, &xscr) < 0) {
+ xdl_free_env(&xe);
+ return -1;
+ }
+ if (!xscr) {
+ /* If this happens, the changes are identical. */
+ xdl_free_env(&xe);
+ m->mode = 4;
+ continue;
+ }
+ x = xscr;
+ m->i1 = xscr->i1 + i1;
+ m->chg1 = xscr->chg1;
+ m->i2 = xscr->i2 + i2;
+ m->chg2 = xscr->chg2;
+ while (xscr->next) {
+ xdmerge_t *m2 = xdl_malloc(sizeof(xdmerge_t));
+ if (!m2) {
+ xdl_free_env(&xe);
+ xdl_free_script(x);
+ return -1;
+ }
+ xscr = xscr->next;
+ m2->next = m->next;
+ m->next = m2;
+ m = m2;
+ m->mode = 0;
+ m->i1 = xscr->i1 + i1;
+ m->chg1 = xscr->chg1;
+ m->i2 = xscr->i2 + i2;
+ m->chg2 = xscr->chg2;
+ }
+ xdl_free_env(&xe);
+ xdl_free_script(x);
+ }
+ return 0;
+}
+
+static int line_contains_alnum(const char *ptr, long size)
+{
+ while (size--)
+ if (isalnum(*(ptr++)))
+ return 1;
+ return 0;
+}
+
+static int lines_contain_alnum(xdfenv_t *xe, int i, int chg)
+{
+ for (; chg; chg--, i++)
+ if (line_contains_alnum(xe->xdf2.recs[i]->ptr,
+ xe->xdf2.recs[i]->size))
+ return 1;
+ return 0;
+}
+
+/*
+ * This function merges m and m->next, marking everything between those hunks
+ * as conflicting, too.
+ */
+static void xdl_merge_two_conflicts(xdmerge_t *m)
+{
+ xdmerge_t *next_m = m->next;
+ m->chg1 = next_m->i1 + next_m->chg1 - m->i1;
+ m->chg2 = next_m->i2 + next_m->chg2 - m->i2;
+ m->next = next_m->next;
+ free(next_m);
+}
+
+/*
+ * If there are less than 3 non-conflicting lines between conflicts,
+ * it appears simpler -- because it takes up less (or as many) lines --
+ * if the lines are moved into the conflicts.
+ */
+static int xdl_simplify_non_conflicts(xdfenv_t *xe1, xdmerge_t *m,
+ int simplify_if_no_alnum)
+{
+ int result = 0;
+
+ if (!m)
+ return result;
+ for (;;) {
+ xdmerge_t *next_m = m->next;
+ int begin, end;
+
+ if (!next_m)
+ return result;
+
+ begin = m->i1 + m->chg1;
+ end = next_m->i1;
+
+ if (m->mode != 0 || next_m->mode != 0 ||
+ (end - begin > 3 &&
+ (!simplify_if_no_alnum ||
+ lines_contain_alnum(xe1, begin, end - begin)))) {
+ m = next_m;
+ } else {
+ result++;
+ xdl_merge_two_conflicts(m);
+ }
+ }
+}
+
+/*
+ * level == 0: mark all overlapping changes as conflict
+ * level == 1: mark overlapping changes as conflict only if not identical
+ * level == 2: analyze non-identical changes for minimal conflict set
+ * level == 3: analyze non-identical changes for minimal conflict set, but
+ * treat hunks not containing any letter or number as conflicting
+ *
+ * returns < 0 on error, == 0 for no conflicts, else number of conflicts
+ */
+static int xdl_do_merge(xdfenv_t *xe1, xdchange_t *xscr1, const char *name1,
+ xdfenv_t *xe2, xdchange_t *xscr2, const char *name2,
+ int flags, xpparam_t const *xpp, mmbuffer_t *result) {
+ xdmerge_t *changes, *c;
+ int i0, i1, i2, chg0, chg1, chg2;
+ int level = flags & XDL_MERGE_LEVEL_MASK;
+ int style = flags & XDL_MERGE_STYLE_MASK;
+
+ if (style == XDL_MERGE_DIFF3) {
+ /*
+ * "diff3 -m" output does not make sense for anything
+ * more aggressive than XDL_MERGE_EAGER.
+ */
+ if (XDL_MERGE_EAGER < level)
+ level = XDL_MERGE_EAGER;
+ }
+
+ c = changes = NULL;
+
+ while (xscr1 && xscr2) {
+ if (!changes)
+ changes = c;
+ if (xscr1->i1 + xscr1->chg1 < xscr2->i1) {
+ i0 = xscr1->i1;
+ i1 = xscr1->i2;
+ i2 = xscr2->i2 - xscr2->i1 + xscr1->i1;
+ chg0 = xscr1->chg1;
+ chg1 = xscr1->chg2;
+ chg2 = xscr1->chg1;
+ if (xdl_append_merge(&c, 1,
+ i0, chg0, i1, chg1, i2, chg2)) {
+ xdl_cleanup_merge(changes);
+ return -1;
+ }
+ xscr1 = xscr1->next;
+ continue;
+ }
+ if (xscr2->i1 + xscr2->chg1 < xscr1->i1) {
+ i0 = xscr2->i1;
+ i1 = xscr1->i2 - xscr1->i1 + xscr2->i1;
+ i2 = xscr2->i2;
+ chg0 = xscr2->chg1;
+ chg1 = xscr2->chg1;
+ chg2 = xscr2->chg2;
+ if (xdl_append_merge(&c, 2,
+ i0, chg0, i1, chg1, i2, chg2)) {
+ xdl_cleanup_merge(changes);
+ return -1;
+ }
+ xscr2 = xscr2->next;
+ continue;
+ }
+ if (level == XDL_MERGE_MINIMAL || xscr1->i1 != xscr2->i1 ||
+ xscr1->chg1 != xscr2->chg1 ||
+ xscr1->chg2 != xscr2->chg2 ||
+ xdl_merge_cmp_lines(xe1, xscr1->i2,
+ xe2, xscr2->i2,
+ xscr1->chg2, xpp->flags)) {
+ /* conflict */
+ int off = xscr1->i1 - xscr2->i1;
+ int ffo = off + xscr1->chg1 - xscr2->chg1;
+
+ i0 = xscr1->i1;
+ i1 = xscr1->i2;
+ i2 = xscr2->i2;
+ if (off > 0) {
+ i0 -= off;
+ i1 -= off;
+ }
+ else
+ i2 += off;
+ chg0 = xscr1->i1 + xscr1->chg1 - i0;
+ chg1 = xscr1->i2 + xscr1->chg2 - i1;
+ chg2 = xscr2->i2 + xscr2->chg2 - i2;
+ if (ffo < 0) {
+ chg0 -= ffo;
+ chg1 -= ffo;
+ } else
+ chg2 += ffo;
+ if (xdl_append_merge(&c, 0,
+ i0, chg0, i1, chg1, i2, chg2)) {
+ xdl_cleanup_merge(changes);
+ return -1;
+ }
+ }
+
+ i1 = xscr1->i1 + xscr1->chg1;
+ i2 = xscr2->i1 + xscr2->chg1;
+
+ if (i1 >= i2)
+ xscr2 = xscr2->next;
+ if (i2 >= i1)
+ xscr1 = xscr1->next;
+ }
+ while (xscr1) {
+ if (!changes)
+ changes = c;
+ i0 = xscr1->i1;
+ i1 = xscr1->i2;
+ i2 = xscr1->i1 + xe2->xdf2.nrec - xe2->xdf1.nrec;
+ chg0 = xscr1->chg1;
+ chg1 = xscr1->chg2;
+ chg2 = xscr1->chg1;
+ if (xdl_append_merge(&c, 1,
+ i0, chg0, i1, chg1, i2, chg2)) {
+ xdl_cleanup_merge(changes);
+ return -1;
+ }
+ xscr1 = xscr1->next;
+ }
+ while (xscr2) {
+ if (!changes)
+ changes = c;
+ i0 = xscr2->i1;
+ i1 = xscr2->i1 + xe1->xdf2.nrec - xe1->xdf1.nrec;
+ i2 = xscr2->i2;
+ chg0 = xscr2->chg1;
+ chg1 = xscr2->chg1;
+ chg2 = xscr2->chg2;
+ if (xdl_append_merge(&c, 2,
+ i0, chg0, i1, chg1, i2, chg2)) {
+ xdl_cleanup_merge(changes);
+ return -1;
+ }
+ xscr2 = xscr2->next;
+ }
+ if (!changes)
+ changes = c;
+ /* refine conflicts */
+ if (XDL_MERGE_ZEALOUS <= level &&
+ (xdl_refine_conflicts(xe1, xe2, changes, xpp) < 0 ||
+ xdl_simplify_non_conflicts(xe1, changes,
+ XDL_MERGE_ZEALOUS < level) < 0)) {
+ xdl_cleanup_merge(changes);
+ return -1;
+ }
+ /* output */
+ if (result) {
+ int size = xdl_fill_merge_buffer(xe1, name1, xe2, name2,
+ changes, NULL, style);
+ result->ptr = xdl_malloc(size);
+ if (!result->ptr) {
+ xdl_cleanup_merge(changes);
+ return -1;
+ }
+ result->size = size;
+ xdl_fill_merge_buffer(xe1, name1, xe2, name2, changes,
+ result->ptr, style);
+ }
+ return xdl_cleanup_merge(changes);
+}
+
+int xdl_merge(mmfile_t *orig, mmfile_t *mf1, const char *name1,
+ mmfile_t *mf2, const char *name2,
+ xpparam_t const *xpp, int flags, mmbuffer_t *result) {
+ xdchange_t *xscr1, *xscr2;
+ xdfenv_t xe1, xe2;
+ int status;
+
+ result->ptr = NULL;
+ result->size = 0;
+
+ if (xdl_do_diff(orig, mf1, xpp, &xe1) < 0 ||
+ xdl_do_diff(orig, mf2, xpp, &xe2) < 0) {
+ return -1;
+ }
+ if (xdl_change_compact(&xe1.xdf1, &xe1.xdf2, xpp->flags) < 0 ||
+ xdl_change_compact(&xe1.xdf2, &xe1.xdf1, xpp->flags) < 0 ||
+ xdl_build_script(&xe1, &xscr1) < 0) {
+ xdl_free_env(&xe1);
+ return -1;
+ }
+ if (xdl_change_compact(&xe2.xdf1, &xe2.xdf2, xpp->flags) < 0 ||
+ xdl_change_compact(&xe2.xdf2, &xe2.xdf1, xpp->flags) < 0 ||
+ xdl_build_script(&xe2, &xscr2) < 0) {
+ xdl_free_env(&xe2);
+ return -1;
+ }
+ status = 0;
+ if (xscr1 || xscr2) {
+ if (!xscr1) {
+ result->ptr = xdl_malloc(mf2->size);
+ memcpy(result->ptr, mf2->ptr, mf2->size);
+ result->size = mf2->size;
+ } else if (!xscr2) {
+ result->ptr = xdl_malloc(mf1->size);
+ memcpy(result->ptr, mf1->ptr, mf1->size);
+ result->size = mf1->size;
+ } else {
+ status = xdl_do_merge(&xe1, xscr1, name1,
+ &xe2, xscr2, name2,
+ flags, xpp, result);
+ }
+ xdl_free_script(xscr1);
+ xdl_free_script(xscr2);
+ }
+ xdl_free_env(&xe1);
+ xdl_free_env(&xe2);
+
+ return status;
+}
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