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/*
* Low level 3-way in-core file merge.
*
* Copyright (c) 2007 Junio C Hamano
*/
#include "cache.h"
#include "attr.h"
#include "xdiff-interface.h"
#include "run-command.h"
#include "ll-merge.h"
struct ll_merge_driver;
typedef int (*ll_merge_fn)(const struct ll_merge_driver *,
mmbuffer_t *result,
const char *path,
mmfile_t *orig,
mmfile_t *src1, const char *name1,
mmfile_t *src2, const char *name2,
int virtual_ancestor);
struct ll_merge_driver {
const char *name;
const char *description;
ll_merge_fn fn;
const char *recursive;
struct ll_merge_driver *next;
char *cmdline;
};
/*
* Built-in low-levels
*/
static int ll_binary_merge(const struct ll_merge_driver *drv_unused,
mmbuffer_t *result,
const char *path_unused,
mmfile_t *orig,
mmfile_t *src1, const char *name1,
mmfile_t *src2, const char *name2,
int virtual_ancestor)
{
/*
* The tentative merge result is "ours" for the final round,
* or common ancestor for an internal merge. Still return
* "conflicted merge" status.
*/
mmfile_t *stolen = virtual_ancestor ? orig : src1;
result->ptr = stolen->ptr;
result->size = stolen->size;
stolen->ptr = NULL;
return 1;
}
static int ll_xdl_merge(const struct ll_merge_driver *drv_unused,
mmbuffer_t *result,
const char *path_unused,
mmfile_t *orig,
mmfile_t *src1, const char *name1,
mmfile_t *src2, const char *name2,
int virtual_ancestor)
{
xpparam_t xpp;
int style = 0;
if (buffer_is_binary(orig->ptr, orig->size) ||
buffer_is_binary(src1->ptr, src1->size) ||
buffer_is_binary(src2->ptr, src2->size)) {
warning("Cannot merge binary files: %s vs. %s\n",
name1, name2);
return ll_binary_merge(drv_unused, result,
path_unused,
orig, src1, name1,
src2, name2,
virtual_ancestor);
}
memset(&xpp, 0, sizeof(xpp));
if (git_xmerge_style >= 0)
style = git_xmerge_style;
return xdl_merge(orig,
src1, name1,
src2, name2,
&xpp, XDL_MERGE_ZEALOUS | style,
result);
}
static int ll_union_merge(const struct ll_merge_driver *drv_unused,
mmbuffer_t *result,
const char *path_unused,
mmfile_t *orig,
mmfile_t *src1, const char *name1,
mmfile_t *src2, const char *name2,
int virtual_ancestor)
{
char *src, *dst;
long size;
const int marker_size = 7;
int status, saved_style;
/* We have to force the RCS "merge" style */
saved_style = git_xmerge_style;
git_xmerge_style = 0;
status = ll_xdl_merge(drv_unused, result, path_unused,
orig, src1, NULL, src2, NULL,
virtual_ancestor);
git_xmerge_style = saved_style;
if (status <= 0)
return status;
size = result->size;
src = dst = result->ptr;
while (size) {
char ch;
if ((marker_size < size) &&
(*src == '<' || *src == '=' || *src == '>')) {
int i;
ch = *src;
for (i = 0; i < marker_size; i++)
if (src[i] != ch)
goto not_a_marker;
if (src[marker_size] != '\n')
goto not_a_marker;
src += marker_size + 1;
size -= marker_size + 1;
continue;
}
not_a_marker:
do {
ch = *src++;
*dst++ = ch;
size--;
} while (ch != '\n' && size);
}
result->size = dst - result->ptr;
return 0;
}
#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)
{
int fd;
strcpy(path, ".merge_file_XXXXXX");
fd = xmkstemp(path);
if (write_in_full(fd, src->ptr, src->size) != src->size)
die("unable to write temp-file");
close(fd);
}
/*
* User defined low-level merge driver support.
*/
static int ll_ext_merge(const struct ll_merge_driver *fn,
mmbuffer_t *result,
const char *path,
mmfile_t *orig,
mmfile_t *src1, const char *name1,
mmfile_t *src2, const char *name2,
int virtual_ancestor)
{
char temp[3][50];
struct strbuf cmd = STRBUF_INIT;
struct strbuf_expand_dict_entry dict[] = {
{ "O", temp[0] },
{ "A", temp[1] },
{ "B", temp[2] },
{ NULL }
};
struct child_process child;
const char *args[20];
int status, fd, i;
struct stat st;
if (fn->cmdline == NULL)
die("custom merge driver %s lacks command line.", fn->name);
result->ptr = NULL;
result->size = 0;
create_temp(orig, temp[0]);
create_temp(src1, temp[1]);
create_temp(src2, temp[2]);
strbuf_expand(&cmd, fn->cmdline, strbuf_expand_dict_cb, &dict);
memset(&child, 0, sizeof(child));
child.argv = args;
args[0] = "sh";
args[1] = "-c";
args[2] = cmd.buf;
args[3] = NULL;
status = run_command(&child);
if (status < -ERR_RUN_COMMAND_FORK)
; /* failure in run-command */
else
status = -status;
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 = xmalloc(result->size + 1);
if (read_in_full(fd, result->ptr, result->size) != result->size) {
free(result->ptr);
result->ptr = NULL;
result->size = 0;
}
close_bad:
close(fd);
bad:
for (i = 0; i < 3; i++)
unlink(temp[i]);
strbuf_release(&cmd);
return status;
}
/*
* 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)
{
struct ll_merge_driver *fn;
const char *ep, *name;
int namelen;
if (!strcmp(var, "merge.default")) {
if (value)
default_ll_merge = strdup(value);
return 0;
}
/*
* 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 (prefixcmp(var, "merge.") || (ep = strrchr(var, '.')) == var + 5)
return 0;
/*
* Find existing one as we might be processing merge.<name>.var2
* after seeing merge.<name>.var1.
*/
name = var + 6;
namelen = ep - name;
for (fn = ll_user_merge; fn; fn = fn->next)
if (!strncmp(fn->name, name, namelen) && !fn->name[namelen])
break;
if (!fn) {
fn = xcalloc(1, sizeof(struct ll_merge_driver));
fn->name = xmemdupz(name, namelen);
fn->fn = ll_ext_merge;
*ll_user_merge_tail = fn;
ll_user_merge_tail = &(fn->next);
}
ep++;
if (!strcmp("name", ep)) {
if (!value)
return error("%s: lacks value", var);
fn->description = strdup(value);
return 0;
}
if (!strcmp("driver", ep)) {
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.
*
* 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 = strdup(value);
return 0;
}
if (!strcmp("recursive", ep)) {
if (!value)
return error("%s: lacks value", var);
fn->recursive = strdup(value);
return 0;
}
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 const char *git_path_check_merge(const char *path)
{
static struct git_attr_check attr_merge_check;
if (!attr_merge_check.attr)
attr_merge_check.attr = git_attr("merge", 5);
if (git_checkattr(path, 1, &attr_merge_check))
return NULL;
return attr_merge_check.value;
}
int ll_merge(mmbuffer_t *result_buf,
const char *path,
mmfile_t *ancestor,
mmfile_t *ours, const char *our_label,
mmfile_t *theirs, const char *their_label,
int virtual_ancestor)
{
const char *ll_driver_name;
const struct ll_merge_driver *driver;
ll_driver_name = git_path_check_merge(path);
driver = find_ll_merge_driver(ll_driver_name);
if (virtual_ancestor && driver->recursive)
driver = find_ll_merge_driver(driver->recursive);
return driver->fn(driver, result_buf, path,
ancestor,
ours, our_label,
theirs, their_label, virtual_ancestor);
}
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