git/ll-merge.c
Junio C Hamano 67a3b2b39f Merge branch 'jc/attr-source-tree'
"git --attr-source=<tree> cmd $args" is a new way to have any
command to read attributes not from the working tree but from the
given tree object.

* jc/attr-source-tree:
  attr: teach "--attr-source=<tree>" global option to "git"
2023-05-17 10:11:41 -07:00

433 lines
11 KiB
C

/*
* Low level 3-way in-core file merge.
*
* Copyright (c) 2007 Junio C Hamano
*/
#include "git-compat-util.h"
#include "config.h"
#include "convert.h"
#include "attr.h"
#include "xdiff-interface.h"
#include "run-command.h"
#include "ll-merge.h"
#include "quote.h"
#include "strbuf.h"
#include "wrapper.h"
struct ll_merge_driver;
typedef enum ll_merge_result (*ll_merge_fn)(const struct ll_merge_driver *,
mmbuffer_t *result,
const char *path,
mmfile_t *orig, const char *orig_name,
mmfile_t *src1, const char *name1,
mmfile_t *src2, const char *name2,
const struct ll_merge_options *opts,
int marker_size);
struct ll_merge_driver {
const char *name;
const char *description;
ll_merge_fn fn;
const char *recursive;
struct ll_merge_driver *next;
char *cmdline;
};
static struct attr_check *merge_attributes;
static struct attr_check *load_merge_attributes(void)
{
if (!merge_attributes)
merge_attributes = attr_check_initl("merge", "conflict-marker-size", NULL);
return merge_attributes;
}
void reset_merge_attributes(void)
{
attr_check_free(merge_attributes);
merge_attributes = NULL;
}
/*
* Built-in low-levels
*/
static enum ll_merge_result ll_binary_merge(const struct ll_merge_driver *drv UNUSED,
mmbuffer_t *result,
const char *path UNUSED,
mmfile_t *orig, const char *orig_name UNUSED,
mmfile_t *src1, const char *name1 UNUSED,
mmfile_t *src2, const char *name2 UNUSED,
const struct ll_merge_options *opts,
int marker_size UNUSED)
{
enum ll_merge_result ret;
mmfile_t *stolen;
assert(opts);
/*
* The tentative merge result is the common ancestor for an
* internal merge. For the final merge, it is "ours" by
* default but -Xours/-Xtheirs can tweak the choice.
*/
if (opts->virtual_ancestor) {
stolen = orig;
ret = LL_MERGE_OK;
} else {
switch (opts->variant) {
default:
ret = LL_MERGE_BINARY_CONFLICT;
stolen = src1;
break;
case XDL_MERGE_FAVOR_OURS:
ret = LL_MERGE_OK;
stolen = src1;
break;
case XDL_MERGE_FAVOR_THEIRS:
ret = LL_MERGE_OK;
stolen = src2;
break;
}
}
result->ptr = stolen->ptr;
result->size = stolen->size;
stolen->ptr = NULL;
return ret;
}
static enum ll_merge_result ll_xdl_merge(const struct ll_merge_driver *drv_unused,
mmbuffer_t *result,
const char *path,
mmfile_t *orig, const char *orig_name,
mmfile_t *src1, const char *name1,
mmfile_t *src2, const char *name2,
const struct ll_merge_options *opts,
int marker_size)
{
enum ll_merge_result ret;
xmparam_t xmp;
int status;
assert(opts);
if (orig->size > MAX_XDIFF_SIZE ||
src1->size > MAX_XDIFF_SIZE ||
src2->size > MAX_XDIFF_SIZE ||
buffer_is_binary(orig->ptr, orig->size) ||
buffer_is_binary(src1->ptr, src1->size) ||
buffer_is_binary(src2->ptr, src2->size)) {
return ll_binary_merge(drv_unused, result,
path,
orig, orig_name,
src1, name1,
src2, name2,
opts, marker_size);
}
memset(&xmp, 0, sizeof(xmp));
xmp.level = XDL_MERGE_ZEALOUS;
xmp.favor = opts->variant;
xmp.xpp.flags = opts->xdl_opts;
if (git_xmerge_style >= 0)
xmp.style = git_xmerge_style;
if (marker_size > 0)
xmp.marker_size = marker_size;
xmp.ancestor = orig_name;
xmp.file1 = name1;
xmp.file2 = name2;
status = xdl_merge(orig, src1, src2, &xmp, result);
ret = (status > 0) ? LL_MERGE_CONFLICT : status;
return ret;
}
static enum ll_merge_result ll_union_merge(const struct ll_merge_driver *drv_unused,
mmbuffer_t *result,
const char *path,
mmfile_t *orig, const char *orig_name,
mmfile_t *src1, const char *name1,
mmfile_t *src2, const char *name2,
const struct ll_merge_options *opts,
int marker_size)
{
/* Use union favor */
struct ll_merge_options o;
assert(opts);
o = *opts;
o.variant = XDL_MERGE_FAVOR_UNION;
return ll_xdl_merge(drv_unused, result, path,
orig, orig_name, src1, name1, src2, name2,
&o, marker_size);
}
#define LL_BINARY_MERGE 0
#define LL_TEXT_MERGE 1
#define LL_UNION_MERGE 2
static struct ll_merge_driver ll_merge_drv[] = {
{ "binary", "built-in binary merge", ll_binary_merge },
{ "text", "built-in 3-way text merge", ll_xdl_merge },
{ "union", "built-in union merge", ll_union_merge },
};
static void create_temp(mmfile_t *src, char *path, size_t len)
{
int fd;
xsnprintf(path, len, ".merge_file_XXXXXX");
fd = xmkstemp(path);
if (write_in_full(fd, src->ptr, src->size) < 0)
die_errno("unable to write temp-file");
close(fd);
}
/*
* User defined low-level merge driver support.
*/
static enum ll_merge_result ll_ext_merge(const struct ll_merge_driver *fn,
mmbuffer_t *result,
const char *path,
mmfile_t *orig, const char *orig_name UNUSED,
mmfile_t *src1, const char *name1 UNUSED,
mmfile_t *src2, const char *name2 UNUSED,
const struct ll_merge_options *opts,
int marker_size)
{
char temp[4][50];
struct strbuf cmd = STRBUF_INIT;
struct strbuf_expand_dict_entry dict[6];
struct strbuf path_sq = STRBUF_INIT;
struct child_process child = CHILD_PROCESS_INIT;
int status, fd, i;
struct stat st;
enum ll_merge_result ret;
assert(opts);
sq_quote_buf(&path_sq, path);
dict[0].placeholder = "O"; dict[0].value = temp[0];
dict[1].placeholder = "A"; dict[1].value = temp[1];
dict[2].placeholder = "B"; dict[2].value = temp[2];
dict[3].placeholder = "L"; dict[3].value = temp[3];
dict[4].placeholder = "P"; dict[4].value = path_sq.buf;
dict[5].placeholder = NULL; dict[5].value = NULL;
if (!fn->cmdline)
die("custom merge driver %s lacks command line.", fn->name);
result->ptr = NULL;
result->size = 0;
create_temp(orig, temp[0], sizeof(temp[0]));
create_temp(src1, temp[1], sizeof(temp[1]));
create_temp(src2, temp[2], sizeof(temp[2]));
xsnprintf(temp[3], sizeof(temp[3]), "%d", marker_size);
strbuf_expand(&cmd, fn->cmdline, strbuf_expand_dict_cb, &dict);
child.use_shell = 1;
strvec_push(&child.args, cmd.buf);
status = run_command(&child);
fd = open(temp[1], O_RDONLY);
if (fd < 0)
goto bad;
if (fstat(fd, &st))
goto close_bad;
result->size = st.st_size;
result->ptr = xmallocz(result->size);
if (read_in_full(fd, result->ptr, result->size) != result->size) {
FREE_AND_NULL(result->ptr);
result->size = 0;
}
close_bad:
close(fd);
bad:
for (i = 0; i < 3; i++)
unlink_or_warn(temp[i]);
strbuf_release(&cmd);
strbuf_release(&path_sq);
ret = (status > 0) ? LL_MERGE_CONFLICT : status;
return ret;
}
/*
* merge.default and merge.driver configuration items
*/
static struct ll_merge_driver *ll_user_merge, **ll_user_merge_tail;
static const char *default_ll_merge;
static int read_merge_config(const char *var, const char *value,
void *cb UNUSED)
{
struct ll_merge_driver *fn;
const char *key, *name;
size_t namelen;
if (!strcmp(var, "merge.default"))
return git_config_string(&default_ll_merge, var, value);
/*
* We are not interested in anything but "merge.<name>.variable";
* especially, we do not want to look at variables such as
* "merge.summary", "merge.tool", and "merge.verbosity".
*/
if (parse_config_key(var, "merge", &name, &namelen, &key) < 0 || !name)
return 0;
/*
* Find existing one as we might be processing merge.<name>.var2
* after seeing merge.<name>.var1.
*/
for (fn = ll_user_merge; fn; fn = fn->next)
if (!strncmp(fn->name, name, namelen) && !fn->name[namelen])
break;
if (!fn) {
CALLOC_ARRAY(fn, 1);
fn->name = xmemdupz(name, namelen);
fn->fn = ll_ext_merge;
*ll_user_merge_tail = fn;
ll_user_merge_tail = &(fn->next);
}
if (!strcmp("name", key))
return git_config_string(&fn->description, var, value);
if (!strcmp("driver", key)) {
if (!value)
return error("%s: lacks value", var);
/*
* merge.<name>.driver specifies the command line:
*
* command-line
*
* The command-line will be interpolated with the following
* tokens and is given to the shell:
*
* %O - temporary file name for the merge base.
* %A - temporary file name for our version.
* %B - temporary file name for the other branches' version.
* %L - conflict marker length
* %P - the original path (safely quoted for the shell)
*
* The external merge driver should write the results in the
* file named by %A, and signal that it has done with zero exit
* status.
*/
fn->cmdline = xstrdup(value);
return 0;
}
if (!strcmp("recursive", key))
return git_config_string(&fn->recursive, var, value);
return 0;
}
static void initialize_ll_merge(void)
{
if (ll_user_merge_tail)
return;
ll_user_merge_tail = &ll_user_merge;
git_config(read_merge_config, NULL);
}
static const struct ll_merge_driver *find_ll_merge_driver(const char *merge_attr)
{
struct ll_merge_driver *fn;
const char *name;
int i;
initialize_ll_merge();
if (ATTR_TRUE(merge_attr))
return &ll_merge_drv[LL_TEXT_MERGE];
else if (ATTR_FALSE(merge_attr))
return &ll_merge_drv[LL_BINARY_MERGE];
else if (ATTR_UNSET(merge_attr)) {
if (!default_ll_merge)
return &ll_merge_drv[LL_TEXT_MERGE];
else
name = default_ll_merge;
}
else
name = merge_attr;
for (fn = ll_user_merge; fn; fn = fn->next)
if (!strcmp(fn->name, name))
return fn;
for (i = 0; i < ARRAY_SIZE(ll_merge_drv); i++)
if (!strcmp(ll_merge_drv[i].name, name))
return &ll_merge_drv[i];
/* default to the 3-way */
return &ll_merge_drv[LL_TEXT_MERGE];
}
static void normalize_file(mmfile_t *mm, const char *path, struct index_state *istate)
{
struct strbuf strbuf = STRBUF_INIT;
if (renormalize_buffer(istate, path, mm->ptr, mm->size, &strbuf)) {
free(mm->ptr);
mm->size = strbuf.len;
mm->ptr = strbuf_detach(&strbuf, NULL);
}
}
enum ll_merge_result ll_merge(mmbuffer_t *result_buf,
const char *path,
mmfile_t *ancestor, const char *ancestor_label,
mmfile_t *ours, const char *our_label,
mmfile_t *theirs, const char *their_label,
struct index_state *istate,
const struct ll_merge_options *opts)
{
struct attr_check *check = load_merge_attributes();
static const struct ll_merge_options default_opts;
const char *ll_driver_name = NULL;
int marker_size = DEFAULT_CONFLICT_MARKER_SIZE;
const struct ll_merge_driver *driver;
if (!opts)
opts = &default_opts;
if (opts->renormalize) {
normalize_file(ancestor, path, istate);
normalize_file(ours, path, istate);
normalize_file(theirs, path, istate);
}
git_check_attr(istate, path, check);
ll_driver_name = check->items[0].value;
if (check->items[1].value) {
marker_size = atoi(check->items[1].value);
if (marker_size <= 0)
marker_size = DEFAULT_CONFLICT_MARKER_SIZE;
}
driver = find_ll_merge_driver(ll_driver_name);
if (opts->virtual_ancestor) {
if (driver->recursive)
driver = find_ll_merge_driver(driver->recursive);
}
if (opts->extra_marker_size) {
marker_size += opts->extra_marker_size;
}
return driver->fn(driver, result_buf, path, ancestor, ancestor_label,
ours, our_label, theirs, their_label,
opts, marker_size);
}
int ll_merge_marker_size(struct index_state *istate, const char *path)
{
static struct attr_check *check;
int marker_size = DEFAULT_CONFLICT_MARKER_SIZE;
if (!check)
check = attr_check_initl("conflict-marker-size", NULL);
git_check_attr(istate, path, check);
if (check->items[0].value) {
marker_size = atoi(check->items[0].value);
if (marker_size <= 0)
marker_size = DEFAULT_CONFLICT_MARKER_SIZE;
}
return marker_size;
}