110 lines
3.2 KiB
Raw Normal View History

* Low level 3-way in-core file merge.
#ifndef LL_MERGE_H
#define LL_MERGE_H
#include "xdiff/xdiff.h"
* Calling sequence:
* ----------------
* - Prepare a `struct ll_merge_options` to record options.
* If you have no special requests, skip this and pass `NULL`
* as the `opts` parameter to use the default options.
* - Allocate an mmbuffer_t variable for the result.
* - Allocate and fill variables with the file's original content
* and two modified versions (using `read_mmfile`, for example).
* - Call `ll_merge()`.
* - Read the merged content from `result_buf.ptr` and `result_buf.size`.
* - Release buffers when finished. A simple
* `free(ancestor.ptr); free(ours.ptr); free(theirs.ptr);
* free(result_buf.ptr);` will do.
* If the modifications do not merge cleanly, `ll_merge` will return a
* nonzero value and `result_buf` will generally include a description of
* the conflict bracketed by markers such as the traditional `<<<<<<<`
* and `>>>>>>>`.
* The `ancestor_label`, `our_label`, and `their_label` parameters are
* used to label the different sides of a conflict if the merge driver
* supports this.
struct index_state;
* This describes the set of options the calling program wants to affect
* the operation of a low-level (single file) merge.
struct ll_merge_options {
* Behave as though this were part of a merge between common ancestors in
* a recursive merge (merges of binary files may need to be handled
* differently in such cases, for example). If a helper program is
* specified by the `[merge "<driver>"] recursive` configuration, it will
* be used.
unsigned virtual_ancestor : 1;
* Resolve local conflicts automatically in favor of one side or the other
* (as in 'git merge-file' `--ours`/`--theirs`/`--union`). Can be `0`,
unsigned variant : 2;
* Resmudge and clean the "base", "theirs" and "ours" files before merging.
* Use this when the merge is likely to have overlapped with a change in
* smudge/clean or end-of-line normalization rules.
unsigned renormalize : 1;
* Increase the length of conflict markers so that nested conflicts
 * can be differentiated.
merge-recursive: increase marker length with depth of recursion Later patches in this series will modify file collision conflict handling (e.g. from rename/add and rename/rename(2to1) conflicts) so that multiply nested conflict markers can arise even before considering conflicts in the virtual merge base. Including the virtual merge base will provide a way to get triply (or higher) nested conflict markers. This new way to get nested conflict markers will force the need for a more general mechanism to extend the length of conflict markers in order to differentiate between different nestings. Along with this change to conflict marker length handling, we want to make sure that we don't regress handling for other types of conflicts with nested conflict markers. Add a more involved testcase using merge.conflictstyle=diff3, where not only does the virtual merge base contain conflicts, but its virtual merge base does as well (i.e. a case with triply nested conflict markers). While there are multiple reasonable ways to handle nested conflict markers in the virtual merge base for this type of situation, the easiest approach that dovetails well with the new needs for the file collision conflict handling is to require that the length of the conflict markers increase with each subsequent nesting. Subsequent patches which change the rename/add and rename/rename(2to1) conflict handling will modify the extra_marker_size flag appropriately for their new needs. Signed-off-by: Elijah Newren <> Signed-off-by: Junio C Hamano <>
2018-11-08 05:40:24 +01:00
unsigned extra_marker_size;
/* Extra xpparam_t flags as defined in xdiff/xdiff.h. */
long xdl_opts;
enum ll_merge_result {
* Perform a three-way single-file merge in core. This is a thin wrapper
* around `xdl_merge` that takes the path and any merge backend specified in
* `.gitattributes` or `.git/info/attributes` into account.
* Returns 0 for a clean merge.
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);
int ll_merge_marker_size(struct index_state *istate, const char *path);
void reset_merge_attributes(void);