/*

* 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"

#include "quote.h"

struct ll_merge_driver;

typedef int (*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 {

};

/*

* Built-in low-levels

*/

static int ll_binary_merge(const struct ll_merge_driver *drv_unused,

int marker_size)

{

mmfile_t *stolen;

assert(opts);

/*

* The tentative merge result is the or common ancestor for an internal merge.

*/

if (opts->virtual_ancestor) {

stolen = orig;

} else {

switch (opts->variant) {

default:

warning("Cannot merge binary files: %s (%s vs. %s)",

path, name1, name2);

/* fallthru */

case XDL_MERGE_FAVOR_OURS:

stolen = src1;

break;

case XDL_MERGE_FAVOR_THEIRS:

stolen = src2;

break;

}

}

result->ptr = stolen->ptr;

result->size = stolen->size;

stolen->ptr = NULL;

/*

* With -Xtheirs or -Xours, we have cleanly merged;

* otherwise we got a conflict.

*/

return (opts->variant ? 0 : 1);

}

static int ll_xdl_merge(const struct ll_merge_driver *drv_unused,

int marker_size)

{

xmparam_t xmp;

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.mark_all = opts->mark_all_changes;

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;

return xdl_merge(orig, src1, src2, &xmp, result);

}

static int ll_union_merge(const struct ll_merge_driver *drv_unused,

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_unused,

orig, NULL, src1, NULL, src2, NULL,

&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) != src->size)

die_errno("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,

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;

const char *args[] = { NULL, NULL };

int status, fd, i;

struct stat st;

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 == NULL)

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);

args[0] = cmd.buf;

status = run_command_v_opt(args, RUN_USING_SHELL);

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_or_warn(temp[i]);

strbuf_release(&cmd);

strbuf_release(&path_sq);

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 *key, *name;

int 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) {

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);

}

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 int git_path_check_merge(const char *path, struct git_attr_check check[2])

{

if (!check[0].attr) {

check[0].attr = git_attr("merge");

check[1].attr = git_attr("conflict-marker-size");

}

return git_check_attr(path, 2, check);

}

static void normalize_file(mmfile_t *mm, const char *path)

{

struct strbuf strbuf = STRBUF_INIT;

if (renormalize_buffer(path, mm->ptr, mm->size, &strbuf)) {

free(mm->ptr);

mm->size = strbuf.len;

mm->ptr = strbuf_detach(&strbuf, NULL);

}

}

int ll_merge(mmbuffer_t *result_buf,

const struct ll_merge_options *opts)

{

static struct git_attr_check check[2];

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);

normalize_file(ours, path);

normalize_file(theirs, path);

}

if (!git_path_check_merge(path, check)) {

ll_driver_name = check[0].value;

if (check[1].value) {

marker_size = atoi(check[1].value);

if (marker_size <= 0)

marker_size = DEFAULT_CONFLICT_MARKER_SIZE;

}

}

driver = find_ll_merge_driver(ll_driver_name);

if (opts->virtual_ancestor && driver->recursive)

driver = find_ll_merge_driver(driver->recursive);

return driver->fn(driver, result_buf, path, ancestor, ancestor_label,

ours, our_label, theirs, their_label,

opts, marker_size);

}

int ll_merge_marker_size(const char *path)

{

static struct git_attr_check check;

int marker_size = DEFAULT_CONFLICT_MARKER_SIZE;

if (!check.attr)

check.attr = git_attr("conflict-marker-size");

if (!git_check_attr(path, 1, &check) && check.value) {

marker_size = atoi(check.value);

if (marker_size <= 0)

marker_size = DEFAULT_CONFLICT_MARKER_SIZE;

}

return marker_size;

}