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![Antonin Delpeuch](/assets/img/avatar_default.png)
Custom merge drivers need access to the names of the revisions they are working on, so that the merge conflict markers they introduce can refer to those revisions. The placeholders '%S', '%X' and '%Y' are introduced to this end. Signed-off-by: Antonin Delpeuch <antonin@delpeuch.eu> Signed-off-by: Junio C Hamano <gitster@pobox.com>
454 lines
12 KiB
C
454 lines
12 KiB
C
/*
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* Low level 3-way in-core file merge.
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*
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* Copyright (c) 2007 Junio C Hamano
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*/
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#include "git-compat-util.h"
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#include "config.h"
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#include "convert.h"
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#include "attr.h"
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#include "xdiff-interface.h"
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#include "run-command.h"
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#include "merge-ll.h"
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#include "quote.h"
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#include "strbuf.h"
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struct ll_merge_driver;
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typedef enum ll_merge_result (*ll_merge_fn)(const struct ll_merge_driver *,
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mmbuffer_t *result,
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const char *path,
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mmfile_t *orig, const char *orig_name,
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mmfile_t *src1, const char *name1,
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mmfile_t *src2, const char *name2,
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const struct ll_merge_options *opts,
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int marker_size);
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struct ll_merge_driver {
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const char *name;
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const char *description;
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ll_merge_fn fn;
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const char *recursive;
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struct ll_merge_driver *next;
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char *cmdline;
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};
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static struct attr_check *merge_attributes;
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static struct attr_check *load_merge_attributes(void)
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{
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if (!merge_attributes)
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merge_attributes = attr_check_initl("merge", "conflict-marker-size", NULL);
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return merge_attributes;
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}
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void reset_merge_attributes(void)
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{
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attr_check_free(merge_attributes);
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merge_attributes = NULL;
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}
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/*
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* Built-in low-levels
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*/
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static enum ll_merge_result ll_binary_merge(const struct ll_merge_driver *drv UNUSED,
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mmbuffer_t *result,
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const char *path UNUSED,
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mmfile_t *orig, const char *orig_name UNUSED,
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mmfile_t *src1, const char *name1 UNUSED,
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mmfile_t *src2, const char *name2 UNUSED,
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const struct ll_merge_options *opts,
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int marker_size UNUSED)
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{
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enum ll_merge_result ret;
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mmfile_t *stolen;
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assert(opts);
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/*
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* The tentative merge result is the common ancestor for an
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* internal merge. For the final merge, it is "ours" by
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* default but -Xours/-Xtheirs can tweak the choice.
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*/
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if (opts->virtual_ancestor) {
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stolen = orig;
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ret = LL_MERGE_OK;
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} else {
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switch (opts->variant) {
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default:
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ret = LL_MERGE_BINARY_CONFLICT;
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stolen = src1;
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break;
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case XDL_MERGE_FAVOR_OURS:
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ret = LL_MERGE_OK;
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stolen = src1;
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break;
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case XDL_MERGE_FAVOR_THEIRS:
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ret = LL_MERGE_OK;
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stolen = src2;
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break;
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}
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}
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result->ptr = stolen->ptr;
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result->size = stolen->size;
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stolen->ptr = NULL;
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return ret;
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}
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static enum ll_merge_result ll_xdl_merge(const struct ll_merge_driver *drv_unused,
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mmbuffer_t *result,
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const char *path,
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mmfile_t *orig, const char *orig_name,
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mmfile_t *src1, const char *name1,
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mmfile_t *src2, const char *name2,
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const struct ll_merge_options *opts,
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int marker_size)
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{
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enum ll_merge_result ret;
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xmparam_t xmp;
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int status;
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assert(opts);
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if (orig->size > MAX_XDIFF_SIZE ||
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src1->size > MAX_XDIFF_SIZE ||
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src2->size > MAX_XDIFF_SIZE ||
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buffer_is_binary(orig->ptr, orig->size) ||
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buffer_is_binary(src1->ptr, src1->size) ||
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buffer_is_binary(src2->ptr, src2->size)) {
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return ll_binary_merge(drv_unused, result,
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path,
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orig, orig_name,
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src1, name1,
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src2, name2,
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opts, marker_size);
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}
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memset(&xmp, 0, sizeof(xmp));
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xmp.level = XDL_MERGE_ZEALOUS;
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xmp.favor = opts->variant;
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xmp.xpp.flags = opts->xdl_opts;
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if (git_xmerge_style >= 0)
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xmp.style = git_xmerge_style;
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if (marker_size > 0)
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xmp.marker_size = marker_size;
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xmp.ancestor = orig_name;
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xmp.file1 = name1;
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xmp.file2 = name2;
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status = xdl_merge(orig, src1, src2, &xmp, result);
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ret = (status > 0) ? LL_MERGE_CONFLICT : status;
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return ret;
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}
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static enum ll_merge_result ll_union_merge(const struct ll_merge_driver *drv_unused,
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mmbuffer_t *result,
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const char *path,
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mmfile_t *orig, const char *orig_name,
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mmfile_t *src1, const char *name1,
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mmfile_t *src2, const char *name2,
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const struct ll_merge_options *opts,
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int marker_size)
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{
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/* Use union favor */
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struct ll_merge_options o;
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assert(opts);
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o = *opts;
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o.variant = XDL_MERGE_FAVOR_UNION;
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return ll_xdl_merge(drv_unused, result, path,
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orig, orig_name, src1, name1, src2, name2,
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&o, marker_size);
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}
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#define LL_BINARY_MERGE 0
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#define LL_TEXT_MERGE 1
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#define LL_UNION_MERGE 2
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static struct ll_merge_driver ll_merge_drv[] = {
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{ "binary", "built-in binary merge", ll_binary_merge },
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{ "text", "built-in 3-way text merge", ll_xdl_merge },
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{ "union", "built-in union merge", ll_union_merge },
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};
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static void create_temp(mmfile_t *src, char *path, size_t len)
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{
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int fd;
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xsnprintf(path, len, ".merge_file_XXXXXX");
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fd = xmkstemp(path);
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if (write_in_full(fd, src->ptr, src->size) < 0)
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die_errno("unable to write temp-file");
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close(fd);
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}
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/*
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* User defined low-level merge driver support.
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*/
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static enum ll_merge_result ll_ext_merge(const struct ll_merge_driver *fn,
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mmbuffer_t *result,
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const char *path,
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mmfile_t *orig, const char *orig_name,
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mmfile_t *src1, const char *name1,
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mmfile_t *src2, const char *name2,
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const struct ll_merge_options *opts,
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int marker_size)
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{
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char temp[3][50];
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struct strbuf cmd = STRBUF_INIT;
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const char *format = fn->cmdline;
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struct child_process child = CHILD_PROCESS_INIT;
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int status, fd, i;
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struct stat st;
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enum ll_merge_result ret;
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assert(opts);
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if (!fn->cmdline)
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die("custom merge driver %s lacks command line.", fn->name);
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result->ptr = NULL;
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result->size = 0;
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create_temp(orig, temp[0], sizeof(temp[0]));
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create_temp(src1, temp[1], sizeof(temp[1]));
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create_temp(src2, temp[2], sizeof(temp[2]));
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while (strbuf_expand_step(&cmd, &format)) {
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if (skip_prefix(format, "%", &format))
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strbuf_addch(&cmd, '%');
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else if (skip_prefix(format, "O", &format))
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strbuf_addstr(&cmd, temp[0]);
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else if (skip_prefix(format, "A", &format))
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strbuf_addstr(&cmd, temp[1]);
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else if (skip_prefix(format, "B", &format))
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strbuf_addstr(&cmd, temp[2]);
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else if (skip_prefix(format, "L", &format))
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strbuf_addf(&cmd, "%d", marker_size);
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else if (skip_prefix(format, "P", &format))
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sq_quote_buf(&cmd, path);
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else if (skip_prefix(format, "S", &format))
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sq_quote_buf(&cmd, orig_name ? orig_name : "");
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else if (skip_prefix(format, "X", &format))
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sq_quote_buf(&cmd, name1 ? name1 : "");
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else if (skip_prefix(format, "Y", &format))
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sq_quote_buf(&cmd, name2 ? name2 : "");
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else
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strbuf_addch(&cmd, '%');
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}
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child.use_shell = 1;
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strvec_push(&child.args, cmd.buf);
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status = run_command(&child);
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fd = open(temp[1], O_RDONLY);
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if (fd < 0)
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goto bad;
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if (fstat(fd, &st))
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goto close_bad;
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result->size = st.st_size;
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result->ptr = xmallocz(result->size);
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if (read_in_full(fd, result->ptr, result->size) != result->size) {
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FREE_AND_NULL(result->ptr);
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result->size = 0;
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}
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close_bad:
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close(fd);
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bad:
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for (i = 0; i < 3; i++)
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unlink_or_warn(temp[i]);
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strbuf_release(&cmd);
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if (!status)
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ret = LL_MERGE_OK;
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else if (status <= 128)
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ret = LL_MERGE_CONFLICT;
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else
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/* died due to a signal: WTERMSIG(status) + 128 */
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ret = LL_MERGE_ERROR;
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return ret;
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}
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/*
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* merge.default and merge.driver configuration items
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*/
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static struct ll_merge_driver *ll_user_merge, **ll_user_merge_tail;
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static const char *default_ll_merge;
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static int read_merge_config(const char *var, const char *value,
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const struct config_context *ctx UNUSED,
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void *cb UNUSED)
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{
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struct ll_merge_driver *fn;
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const char *key, *name;
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size_t namelen;
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if (!strcmp(var, "merge.default"))
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return git_config_string(&default_ll_merge, var, value);
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/*
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* We are not interested in anything but "merge.<name>.variable";
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* especially, we do not want to look at variables such as
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* "merge.summary", "merge.tool", and "merge.verbosity".
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*/
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if (parse_config_key(var, "merge", &name, &namelen, &key) < 0 || !name)
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return 0;
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/*
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* Find existing one as we might be processing merge.<name>.var2
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* after seeing merge.<name>.var1.
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*/
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for (fn = ll_user_merge; fn; fn = fn->next)
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if (!strncmp(fn->name, name, namelen) && !fn->name[namelen])
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break;
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if (!fn) {
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CALLOC_ARRAY(fn, 1);
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fn->name = xmemdupz(name, namelen);
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fn->fn = ll_ext_merge;
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*ll_user_merge_tail = fn;
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ll_user_merge_tail = &(fn->next);
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}
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if (!strcmp("name", key))
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return git_config_string(&fn->description, var, value);
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if (!strcmp("driver", key)) {
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if (!value)
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return config_error_nonbool(var);
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/*
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* merge.<name>.driver specifies the command line:
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*
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* command-line
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*
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* The command-line will be interpolated with the following
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* tokens and is given to the shell:
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*
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* %O - temporary file name for the merge base.
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* %A - temporary file name for our version.
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* %B - temporary file name for the other branches' version.
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* %L - conflict marker length
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* %P - the original path (safely quoted for the shell)
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* %S - the revision for the merge base
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* %X - the revision for our version
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* %Y - the revision for their version
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*
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* If the file is not named indentically in all versions, then each
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* revision is joined with the corresponding path, separated by a colon.
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* The external merge driver should write the results in the
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* file named by %A, and signal that it has done with zero exit
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* status.
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*/
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fn->cmdline = xstrdup(value);
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return 0;
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}
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if (!strcmp("recursive", key))
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return git_config_string(&fn->recursive, var, value);
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return 0;
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}
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static void initialize_ll_merge(void)
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{
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if (ll_user_merge_tail)
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return;
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ll_user_merge_tail = &ll_user_merge;
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git_config(read_merge_config, NULL);
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}
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static const struct ll_merge_driver *find_ll_merge_driver(const char *merge_attr)
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{
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struct ll_merge_driver *fn;
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const char *name;
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int i;
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initialize_ll_merge();
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if (ATTR_TRUE(merge_attr))
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return &ll_merge_drv[LL_TEXT_MERGE];
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else if (ATTR_FALSE(merge_attr))
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return &ll_merge_drv[LL_BINARY_MERGE];
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else if (ATTR_UNSET(merge_attr)) {
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if (!default_ll_merge)
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return &ll_merge_drv[LL_TEXT_MERGE];
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else
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name = default_ll_merge;
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}
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else
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name = merge_attr;
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for (fn = ll_user_merge; fn; fn = fn->next)
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if (!strcmp(fn->name, name))
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return fn;
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for (i = 0; i < ARRAY_SIZE(ll_merge_drv); i++)
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if (!strcmp(ll_merge_drv[i].name, name))
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return &ll_merge_drv[i];
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/* default to the 3-way */
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return &ll_merge_drv[LL_TEXT_MERGE];
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}
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static void normalize_file(mmfile_t *mm, const char *path, struct index_state *istate)
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{
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struct strbuf strbuf = STRBUF_INIT;
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if (renormalize_buffer(istate, path, mm->ptr, mm->size, &strbuf)) {
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free(mm->ptr);
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mm->size = strbuf.len;
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mm->ptr = strbuf_detach(&strbuf, NULL);
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}
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}
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enum ll_merge_result ll_merge(mmbuffer_t *result_buf,
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const char *path,
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mmfile_t *ancestor, const char *ancestor_label,
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mmfile_t *ours, const char *our_label,
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mmfile_t *theirs, const char *their_label,
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struct index_state *istate,
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const struct ll_merge_options *opts)
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{
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struct attr_check *check = load_merge_attributes();
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static const struct ll_merge_options default_opts;
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const char *ll_driver_name = NULL;
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int marker_size = DEFAULT_CONFLICT_MARKER_SIZE;
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const struct ll_merge_driver *driver;
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if (!opts)
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opts = &default_opts;
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if (opts->renormalize) {
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normalize_file(ancestor, path, istate);
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normalize_file(ours, path, istate);
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normalize_file(theirs, path, istate);
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}
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git_check_attr(istate, path, check);
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ll_driver_name = check->items[0].value;
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if (check->items[1].value) {
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marker_size = atoi(check->items[1].value);
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if (marker_size <= 0)
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marker_size = DEFAULT_CONFLICT_MARKER_SIZE;
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}
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driver = find_ll_merge_driver(ll_driver_name);
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if (opts->virtual_ancestor) {
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if (driver->recursive)
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driver = find_ll_merge_driver(driver->recursive);
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}
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if (opts->extra_marker_size) {
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marker_size += opts->extra_marker_size;
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}
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return driver->fn(driver, result_buf, path, ancestor, ancestor_label,
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ours, our_label, theirs, their_label,
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opts, marker_size);
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}
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int ll_merge_marker_size(struct index_state *istate, const char *path)
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{
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static struct attr_check *check;
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int marker_size = DEFAULT_CONFLICT_MARKER_SIZE;
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if (!check)
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check = attr_check_initl("conflict-marker-size", NULL);
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git_check_attr(istate, path, check);
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if (check->items[0].value) {
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marker_size = atoi(check->items[0].value);
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if (marker_size <= 0)
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marker_size = DEFAULT_CONFLICT_MARKER_SIZE;
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}
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return marker_size;
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}
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