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-rw-r--r--ll-merge.c366
1 files changed, 366 insertions, 0 deletions
diff --git a/ll-merge.c b/ll-merge.c
new file mode 100644
index 0000000000..3764a1ab72
--- /dev/null
+++ b/ll-merge.c
@@ -0,0 +1,366 @@
+/*
+ * 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, const char *orig_name,
+ mmfile_t *src1, const char *name1,
+ mmfile_t *src2, const char *name2,
+ int flag,
+ 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;
+};
+
+/*
+ * 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, const char *orig_name,
+ mmfile_t *src1, const char *name1,
+ mmfile_t *src2, const char *name2,
+ int flag, int marker_size)
+{
+ /*
+ * 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 & 01) ? 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,
+ mmfile_t *orig, const char *orig_name,
+ mmfile_t *src1, const char *name1,
+ mmfile_t *src2, const char *name2,
+ int flag, int marker_size)
+{
+ xmparam_t xmp;
+
+ 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 (%s vs. %s)\n",
+ path, name1, name2);
+ return ll_binary_merge(drv_unused, result,
+ path,
+ orig, orig_name,
+ src1, name1,
+ src2, name2,
+ flag, marker_size);
+ }
+
+ memset(&xmp, 0, sizeof(xmp));
+ xmp.level = XDL_MERGE_ZEALOUS;
+ xmp.favor= (flag >> 1) & 03;
+ 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,
+ mmbuffer_t *result,
+ const char *path_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)
+{
+ /* Use union favor */
+ flag = (flag & 1) | (XDL_MERGE_FAVOR_UNION << 1);
+ return ll_xdl_merge(drv_unused, result, path_unused,
+ orig, NULL, src1, NULL, src2, NULL,
+ flag, marker_size);
+ 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_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,
+ 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,
+ int flag, int marker_size)
+{
+ char temp[4][50];
+ struct strbuf cmd = STRBUF_INIT;
+ struct strbuf_expand_dict_entry dict[5];
+ const char *args[] = { NULL, NULL };
+ int status, fd, i;
+ struct stat st;
+
+ 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 = NULL; dict[4].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]);
+ create_temp(src1, temp[1]);
+ create_temp(src2, temp[2]);
+ sprintf(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);
+ 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 = xstrdup(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 = xstrdup(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.
+ * %L - conflict marker length
+ *
+ * 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", ep)) {
+ if (!value)
+ return error("%s: lacks value", var);
+ fn->recursive = xstrdup(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 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_checkattr(path, 2, check);
+}
+
+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)
+{
+ 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 & 01;
+
+ 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 (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);
+}
+
+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_checkattr(path, 1, &check) && check.value) {
+ marker_size = atoi(check.value);
+ if (marker_size <= 0)
+ marker_size = DEFAULT_CONFLICT_MARKER_SIZE;
+ }
+ return marker_size;
+}
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