ll-merge: replace flag argument with options struct

Keeping track of the flag bits is proving more trouble than it's
worth.  Instead, use a pointer to an options struct like most similar
APIs do.

Callers with no special requests can pass NULL to request the default
options.

Cc: Bert Wesarg <bert.wesarg@googlemail.com>
Cc: Avery Pennarun <apenwarr@gmail.com>
Helped-by: Justin Frankel <justin@cockos.com>
Helped-by: Bert Wesarg <bert.wesarg@googlemail.com>
Signed-off-by: Jonathan Nieder <jrnieder@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

diff --git a/Documentation/technical/api-merge.txt b/Documentation/technical/api-merge.txt
index a7e050bb7acb59764c851b09cd488b6620c0a2dd..9dc1bed768a473317dd77c4d1ed93f65b2c4d483 100644 (file)
--- a/Documentation/technical/api-merge.txt
+++ b/Documentation/technical/api-merge.txt
@@ -17,6 +17,40 @@ responsible for a few things.
    path-specific merge drivers (specified in `.gitattributes`)
    into account.
 
+Data structures
+---------------
+
+* `mmbuffer_t`, `mmfile_t`
+
+These store data usable for use by the xdiff backend, for writing and
+for reading, respectively.  See `xdiff/xdiff.h` for the definitions
+and `diff.c` for examples.
+
+* `struct ll_merge_options`
+
+This describes the set of options the calling program wants to affect
+the operation of a low-level (single file) merge.  Some options:
+
+`virtual_ancestor`::
+       Behave as though this were part of a merge between common
+       ancestors in a recursive merge.
+       If a helper program is specified by the
+       `[merge "<driver>"] recursive` configuration, it will
+       be used (see linkgit:gitattributes[5]).
+
+`variant`::
+       Resolve local conflicts automatically in favor
+       of one side or the other (as in 'git merge-file'
+       `--ours`/`--theirs`/`--union`).  Can be `0`,
+       `XDL_MERGE_FAVOR_OURS`, `XDL_MERGE_FAVOR_THEIRS`, or
+       `XDL_MERGE_FAVOR_UNION`.
+
+`renormalize`::
+       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.
+
 Low-level (single file) merge
 -----------------------------
 
@@ -28,15 +62,24 @@ Low-level (single file) merge
        `.git/info/attributes` into account.  Returns 0 for a
        clean merge.
 
-The caller:
+Calling sequence:
 
-1. allocates an mmbuffer_t variable for the result;
-2. allocates and fills variables with the file's original content
-   and two modified versions (using `read_mmfile`, for example);
-3. calls ll_merge();
-4. reads the output from result_buf.ptr and result_buf.size;
-5. releases buffers when finished (free(ancestor.ptr); free(ours.ptr);
-   free(theirs.ptr); free(result_buf.ptr);).
+* 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
@@ -47,18 +90,6 @@ 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.
 
-The `flag` parameter is a bitfield:
-
- - The `LL_OPT_VIRTUAL_ANCESTOR` bit indicates whether this is an
-   internal merge to consolidate ancestors for a recursive merge.
-
- - The `LL_OPT_FAVOR_MASK` bits allow local conflicts to be automatically
-   resolved in favor of one side or the other (as in 'git merge-file'
-   `--ours`/`--theirs`/`--union`).
-   They can be populated by `create_ll_flag`, whose argument can be
-   `XDL_MERGE_FAVOR_OURS`, `XDL_MERGE_FAVOR_THEIRS`, or
-   `XDL_MERGE_FAVOR_UNION`.
-
 Everything else
 ---------------
 

diff --git a/builtin/checkout.c b/builtin/checkout.c
index 24b67d5dea437ef05af2ca78419f16e6ecd12656..4d36b2897fc4a31795261194a681266dd3a502be 100644 (file)
--- a/builtin/checkout.c
+++ b/builtin/checkout.c
@@ -155,7 +155,7 @@ static int checkout_merged(int pos, struct checkout *state)
         * merge.renormalize set, too
         */
        status = ll_merge(&result_buf, path, &ancestor, "base",
-                         &ours, "ours", &theirs, "theirs", 0);
+                         &ours, "ours", &theirs, "theirs", NULL);
        free(ancestor.ptr);
        free(ours.ptr);
        free(theirs.ptr);

diff --git a/ll-merge.c b/ll-merge.c
index 6bb3095c3a85d771bb60e8f2f025287d16e792df..4d8e321b09aed8ad2381386668fa53069c7223d1 100644 (file)
--- a/ll-merge.c
+++ b/ll-merge.c
@@ -18,7 +18,7 @@ typedef int (*ll_merge_fn)(const struct ll_merge_driver *,
                           mmfile_t *orig, const char *orig_name,
                           mmfile_t *src1, const char *name1,
                           mmfile_t *src2, const char *name2,
-                          int flag,
+                          const struct ll_merge_options *opts,
                           int marker_size);
 
 struct ll_merge_driver {
@@ -39,14 +39,18 @@ static int ll_binary_merge(const struct ll_merge_driver *drv_unused,
                           mmfile_t *orig, const char *orig_name,
                           mmfile_t *src1, const char *name1,
                           mmfile_t *src2, const char *name2,
-                          int flag, int marker_size)
+                          const struct ll_merge_options *opts,
+                          int marker_size)
 {
+       mmfile_t *stolen;
+       assert(opts);
+
        /*
         * 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 = (flag & LL_OPT_VIRTUAL_ANCESTOR) ? orig : src1;
+       stolen = opts->virtual_ancestor ? orig : src1;
 
        result->ptr = stolen->ptr;
        result->size = stolen->size;
@@ -60,9 +64,11 @@ static int ll_xdl_merge(const struct ll_merge_driver *drv_unused,
                        mmfile_t *orig, const char *orig_name,
                        mmfile_t *src1, const char *name1,
                        mmfile_t *src2, const char *name2,
-                       int flag, int marker_size)
+                       const struct ll_merge_options *opts,
+                       int marker_size)
 {
        xmparam_t xmp;
+       assert(opts);
 
        if (buffer_is_binary(orig->ptr, orig->size) ||
            buffer_is_binary(src1->ptr, src1->size) ||
@@ -74,12 +80,12 @@ static int ll_xdl_merge(const struct ll_merge_driver *drv_unused,
                                       orig, orig_name,
                                       src1, name1,
                                       src2, name2,
-                                      flag, marker_size);
+                                      opts, marker_size);
        }
 
        memset(&xmp, 0, sizeof(xmp));
        xmp.level = XDL_MERGE_ZEALOUS;
-       xmp.favor = ll_opt_favor(flag);
+       xmp.favor = opts->variant;
        if (git_xmerge_style >= 0)
                xmp.style = git_xmerge_style;
        if (marker_size > 0)
@@ -96,15 +102,17 @@ static int ll_union_merge(const struct ll_merge_driver *drv_unused,
                          mmfile_t *orig, const char *orig_name,
                          mmfile_t *src1, const char *name1,
                          mmfile_t *src2, const char *name2,
-                         int flag, int marker_size)
+                         const struct ll_merge_options *opts,
+                         int marker_size)
 {
        /* Use union favor */
-       flag &= ~LL_OPT_FAVOR_MASK;
-       flag |= create_ll_flag(XDL_MERGE_FAVOR_UNION);
+       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,
-                           flag, marker_size);
-       return 0;
+                           &o, marker_size);
 }
 
 #define LL_BINARY_MERGE 0
@@ -136,7 +144,8 @@ static int ll_ext_merge(const struct ll_merge_driver *fn,
                        mmfile_t *orig, const char *orig_name,
                        mmfile_t *src1, const char *name1,
                        mmfile_t *src2, const char *name2,
-                       int flag, int marker_size)
+                       const struct ll_merge_options *opts,
+                       int marker_size)
 {
        char temp[4][50];
        struct strbuf cmd = STRBUF_INIT;
@@ -144,6 +153,7 @@ static int ll_ext_merge(const struct ll_merge_driver *fn,
        const char *args[] = { NULL, NULL };
        int status, fd, i;
        struct stat st;
+       assert(opts);
 
        dict[0].placeholder = "O"; dict[0].value = temp[0];
        dict[1].placeholder = "A"; dict[1].value = temp[1];
@@ -337,15 +347,21 @@ int ll_merge(mmbuffer_t *result_buf,
             mmfile_t *ancestor, const char *ancestor_label,
             mmfile_t *ours, const char *our_label,
             mmfile_t *theirs, const char *their_label,
-            int flag)
+            const struct ll_merge_options *opts)
 {
        static struct git_attr_check check[2];
        const char *ll_driver_name = NULL;
        int marker_size = DEFAULT_CONFLICT_MARKER_SIZE;
        const struct ll_merge_driver *driver;
-       int virtual_ancestor = flag & LL_OPT_VIRTUAL_ANCESTOR;
 
-       if (flag & LL_OPT_RENORMALIZE) {
+       if (!opts) {
+               struct ll_merge_options default_opts = {0};
+               return ll_merge(result_buf, path, ancestor, ancestor_label,
+                               ours, our_label, theirs, their_label,
+                               &default_opts);
+       }
+
+       if (opts->renormalize) {
                normalize_file(ancestor, path);
                normalize_file(ours, path);
                normalize_file(theirs, path);
@@ -359,11 +375,11 @@ int ll_merge(mmbuffer_t *result_buf,
                }
        }
        driver = find_ll_merge_driver(ll_driver_name);
-       if (virtual_ancestor && driver->recursive)
+       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,
-                         flag, marker_size);
+                         opts, marker_size);
 }
 
 int ll_merge_marker_size(const char *path)

diff --git a/ll-merge.h b/ll-merge.h
index ff7ca87bfa01d0e9705f4bfd83b9e4d2c155d588..4b707f06c00009871a2c6a840f6b3cc9d117143a 100644 (file)
--- a/ll-merge.h
+++ b/ll-merge.h
@@ -5,27 +5,18 @@
 #ifndef LL_MERGE_H
 #define LL_MERGE_H
 
-#define LL_OPT_VIRTUAL_ANCESTOR        (1 << 0)
-#define LL_OPT_FAVOR_MASK      ((1 << 1) | (1 << 2))
-#define LL_OPT_FAVOR_SHIFT 1
-#define LL_OPT_RENORMALIZE     (1 << 3)
-
-static inline int ll_opt_favor(int flag)
-{
-       return (flag & LL_OPT_FAVOR_MASK) >> LL_OPT_FAVOR_SHIFT;
-}
-
-static inline int create_ll_flag(int favor)
-{
-       return ((favor << LL_OPT_FAVOR_SHIFT) & LL_OPT_FAVOR_MASK);
-}
+struct ll_merge_options {
+       unsigned virtual_ancestor : 1;
+       unsigned variant : 2;   /* favor ours, favor theirs, or union merge */
+       unsigned renormalize : 1;
+};
 
 int 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,
-            int flag);
+            const struct ll_merge_options *opts);
 
 int ll_merge_marker_size(const char *path);
 

diff --git a/merge-file.c b/merge-file.c
index db4d0d50d32d8852d1cb5173125e4173c3badb49..f7f4533926e35867725db00f0c89522c4b290898 100644 (file)
--- a/merge-file.c
+++ b/merge-file.c
@@ -37,7 +37,7 @@ static void *three_way_filemerge(const char *path, mmfile_t *base, mmfile_t *our
         * common ancestor.
         */
        merge_status = ll_merge(&res, path, base, NULL,
-                               our, ".our", their, ".their", 0);
+                               our, ".our", their, ".their", NULL);
        if (merge_status < 0)
                return NULL;
 

diff --git a/merge-recursive.c b/merge-recursive.c
index 44576b79278107534f40cb2d3c7712b50e91fdc3..0e9a29d329535fa6739f51e63a87a5802ab886ec 100644 (file)
--- a/merge-recursive.c
+++ b/merge-recursive.c
@@ -608,22 +608,25 @@ static int merge_3way(struct merge_options *o,
                      const char *branch2)
 {
        mmfile_t orig, src1, src2;
+       struct ll_merge_options ll_opts = {0};
        char *base_name, *name1, *name2;
        int merge_status;
-       int favor;
 
-       if (o->call_depth)
-               favor = 0;
-       else {
+       ll_opts.renormalize = o->renormalize;
+
+       if (o->call_depth) {
+               ll_opts.virtual_ancestor = 1;
+               ll_opts.variant = 0;
+       } else {
                switch (o->recursive_variant) {
                case MERGE_RECURSIVE_OURS:
-                       favor = XDL_MERGE_FAVOR_OURS;
+                       ll_opts.variant = XDL_MERGE_FAVOR_OURS;
                        break;
                case MERGE_RECURSIVE_THEIRS:
-                       favor = XDL_MERGE_FAVOR_THEIRS;
+                       ll_opts.variant = XDL_MERGE_FAVOR_THEIRS;
                        break;
                default:
-                       favor = 0;
+                       ll_opts.variant = 0;
                        break;
                }
        }
@@ -646,10 +649,7 @@ static int merge_3way(struct merge_options *o,
        read_mmblob(&src2, b->sha1);
 
        merge_status = ll_merge(result_buf, a->path, &orig, base_name,
-                               &src1, name1, &src2, name2,
-                               ((o->call_depth ? LL_OPT_VIRTUAL_ANCESTOR : 0) |
-                                (o->renormalize ? LL_OPT_RENORMALIZE : 0) |
-                                create_ll_flag(favor)));
+                               &src1, name1, &src2, name2, &ll_opts);
 
        free(name1);
        free(name2);

diff --git a/rerere.c b/rerere.c
index e40af0df8754a1f08877d40a3d9cda247aecd48e..b180218d0d5420ea9205ffc8e9fccf37e1dc65c8 100644 (file)
--- a/rerere.c
+++ b/rerere.c
@@ -325,7 +325,7 @@ static int handle_cache(const char *path, unsigned char *sha1, const char *outpu
         */
        ll_merge(&result, path, &mmfile[0], NULL,
                 &mmfile[1], "ours",
-                &mmfile[2], "theirs", 0);
+                &mmfile[2], "theirs", NULL);
        for (i = 0; i < 3; i++)
                free(mmfile[i].ptr);