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![Alex Riesen](/assets/img/avatar_default.png)
This helps to notice when something's going wrong, especially on systems which lock open files. I used the following criteria when selecting the code for replacement: - it was already printing a warning for the unlink failures - it is in a function which already printing something or is called from such a function - it is in a static function, returning void and the function is only called from a builtin main function (cmd_) - it is in a function which handles emergency exit (signal handlers) - it is in a function which is obvously cleaning up the lockfiles Signed-off-by: Alex Riesen <raa.lkml@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
385 lines
8.9 KiB
C
385 lines
8.9 KiB
C
/*
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* Low level 3-way in-core file merge.
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*
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* Copyright (c) 2007 Junio C Hamano
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*/
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#include "cache.h"
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#include "attr.h"
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#include "xdiff-interface.h"
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#include "run-command.h"
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#include "ll-merge.h"
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struct ll_merge_driver;
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typedef int (*ll_merge_fn)(const struct ll_merge_driver *,
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mmbuffer_t *result,
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const char *path,
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mmfile_t *orig,
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mmfile_t *src1, const char *name1,
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mmfile_t *src2, const char *name2,
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int virtual_ancestor);
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struct ll_merge_driver {
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const char *name;
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const char *description;
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ll_merge_fn fn;
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const char *recursive;
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struct ll_merge_driver *next;
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char *cmdline;
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};
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/*
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* Built-in low-levels
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*/
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static int ll_binary_merge(const struct ll_merge_driver *drv_unused,
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mmbuffer_t *result,
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const char *path_unused,
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mmfile_t *orig,
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mmfile_t *src1, const char *name1,
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mmfile_t *src2, const char *name2,
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int virtual_ancestor)
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{
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/*
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* The tentative merge result is "ours" for the final round,
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* or common ancestor for an internal merge. Still return
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* "conflicted merge" status.
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*/
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mmfile_t *stolen = virtual_ancestor ? orig : src1;
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result->ptr = stolen->ptr;
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result->size = stolen->size;
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stolen->ptr = NULL;
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return 1;
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}
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static int ll_xdl_merge(const struct ll_merge_driver *drv_unused,
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mmbuffer_t *result,
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const char *path_unused,
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mmfile_t *orig,
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mmfile_t *src1, const char *name1,
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mmfile_t *src2, const char *name2,
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int virtual_ancestor)
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{
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xpparam_t xpp;
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int style = 0;
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if (buffer_is_binary(orig->ptr, orig->size) ||
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buffer_is_binary(src1->ptr, src1->size) ||
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buffer_is_binary(src2->ptr, src2->size)) {
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warning("Cannot merge binary files: %s vs. %s\n",
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name1, name2);
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return ll_binary_merge(drv_unused, result,
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path_unused,
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orig, src1, name1,
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src2, name2,
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virtual_ancestor);
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}
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memset(&xpp, 0, sizeof(xpp));
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if (git_xmerge_style >= 0)
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style = git_xmerge_style;
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return xdl_merge(orig,
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src1, name1,
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src2, name2,
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&xpp, XDL_MERGE_ZEALOUS | style,
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result);
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}
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static int ll_union_merge(const struct ll_merge_driver *drv_unused,
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mmbuffer_t *result,
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const char *path_unused,
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mmfile_t *orig,
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mmfile_t *src1, const char *name1,
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mmfile_t *src2, const char *name2,
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int virtual_ancestor)
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{
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char *src, *dst;
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long size;
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const int marker_size = 7;
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int status, saved_style;
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/* We have to force the RCS "merge" style */
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saved_style = git_xmerge_style;
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git_xmerge_style = 0;
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status = ll_xdl_merge(drv_unused, result, path_unused,
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orig, src1, NULL, src2, NULL,
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virtual_ancestor);
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git_xmerge_style = saved_style;
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if (status <= 0)
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return status;
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size = result->size;
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src = dst = result->ptr;
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while (size) {
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char ch;
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if ((marker_size < size) &&
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(*src == '<' || *src == '=' || *src == '>')) {
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int i;
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ch = *src;
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for (i = 0; i < marker_size; i++)
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if (src[i] != ch)
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goto not_a_marker;
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if (src[marker_size] != '\n')
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goto not_a_marker;
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src += marker_size + 1;
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size -= marker_size + 1;
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continue;
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}
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not_a_marker:
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do {
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ch = *src++;
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*dst++ = ch;
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size--;
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} while (ch != '\n' && size);
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}
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result->size = dst - result->ptr;
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return 0;
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}
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#define LL_BINARY_MERGE 0
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#define LL_TEXT_MERGE 1
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#define LL_UNION_MERGE 2
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static struct ll_merge_driver ll_merge_drv[] = {
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{ "binary", "built-in binary merge", ll_binary_merge },
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{ "text", "built-in 3-way text merge", ll_xdl_merge },
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{ "union", "built-in union merge", ll_union_merge },
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};
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static void create_temp(mmfile_t *src, char *path)
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{
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int fd;
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strcpy(path, ".merge_file_XXXXXX");
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fd = xmkstemp(path);
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if (write_in_full(fd, src->ptr, src->size) != src->size)
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die("unable to write temp-file");
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close(fd);
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}
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/*
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* User defined low-level merge driver support.
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*/
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static int ll_ext_merge(const struct ll_merge_driver *fn,
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mmbuffer_t *result,
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const char *path,
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mmfile_t *orig,
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mmfile_t *src1, const char *name1,
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mmfile_t *src2, const char *name2,
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int virtual_ancestor)
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{
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char temp[3][50];
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struct strbuf cmd = STRBUF_INIT;
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struct strbuf_expand_dict_entry dict[] = {
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{ "O", temp[0] },
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{ "A", temp[1] },
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{ "B", temp[2] },
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{ NULL }
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};
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struct child_process child;
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const char *args[20];
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int status, fd, i;
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struct stat st;
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if (fn->cmdline == NULL)
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die("custom merge driver %s lacks command line.", fn->name);
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result->ptr = NULL;
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result->size = 0;
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create_temp(orig, temp[0]);
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create_temp(src1, temp[1]);
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create_temp(src2, temp[2]);
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strbuf_expand(&cmd, fn->cmdline, strbuf_expand_dict_cb, &dict);
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memset(&child, 0, sizeof(child));
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child.argv = args;
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args[0] = "sh";
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args[1] = "-c";
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args[2] = cmd.buf;
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args[3] = NULL;
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status = run_command(&child);
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if (status < -ERR_RUN_COMMAND_FORK)
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; /* failure in run-command */
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else
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status = -status;
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fd = open(temp[1], O_RDONLY);
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if (fd < 0)
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goto bad;
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if (fstat(fd, &st))
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goto close_bad;
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result->size = st.st_size;
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result->ptr = xmalloc(result->size + 1);
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if (read_in_full(fd, result->ptr, result->size) != result->size) {
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free(result->ptr);
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result->ptr = NULL;
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result->size = 0;
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}
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close_bad:
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close(fd);
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bad:
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for (i = 0; i < 3; i++)
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unlink_or_warn(temp[i]);
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strbuf_release(&cmd);
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return status;
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}
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/*
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* merge.default and merge.driver configuration items
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*/
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static struct ll_merge_driver *ll_user_merge, **ll_user_merge_tail;
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static const char *default_ll_merge;
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static int read_merge_config(const char *var, const char *value, void *cb)
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{
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struct ll_merge_driver *fn;
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const char *ep, *name;
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int namelen;
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if (!strcmp(var, "merge.default")) {
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if (value)
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default_ll_merge = strdup(value);
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return 0;
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}
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/*
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* We are not interested in anything but "merge.<name>.variable";
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* especially, we do not want to look at variables such as
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* "merge.summary", "merge.tool", and "merge.verbosity".
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*/
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if (prefixcmp(var, "merge.") || (ep = strrchr(var, '.')) == var + 5)
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return 0;
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/*
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* Find existing one as we might be processing merge.<name>.var2
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* after seeing merge.<name>.var1.
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*/
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name = var + 6;
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namelen = ep - name;
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for (fn = ll_user_merge; fn; fn = fn->next)
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if (!strncmp(fn->name, name, namelen) && !fn->name[namelen])
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break;
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if (!fn) {
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fn = xcalloc(1, sizeof(struct ll_merge_driver));
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fn->name = xmemdupz(name, namelen);
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fn->fn = ll_ext_merge;
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*ll_user_merge_tail = fn;
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ll_user_merge_tail = &(fn->next);
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}
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ep++;
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if (!strcmp("name", ep)) {
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if (!value)
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return error("%s: lacks value", var);
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fn->description = strdup(value);
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return 0;
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}
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if (!strcmp("driver", ep)) {
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if (!value)
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return error("%s: lacks value", var);
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/*
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* merge.<name>.driver specifies the command line:
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*
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* command-line
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*
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* The command-line will be interpolated with the following
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* tokens and is given to the shell:
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*
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* %O - temporary file name for the merge base.
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* %A - temporary file name for our version.
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* %B - temporary file name for the other branches' version.
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*
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* The external merge driver should write the results in the
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* file named by %A, and signal that it has done with zero exit
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* status.
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*/
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fn->cmdline = strdup(value);
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return 0;
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}
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if (!strcmp("recursive", ep)) {
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if (!value)
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return error("%s: lacks value", var);
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fn->recursive = strdup(value);
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return 0;
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}
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return 0;
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}
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static void initialize_ll_merge(void)
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{
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if (ll_user_merge_tail)
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return;
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ll_user_merge_tail = &ll_user_merge;
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git_config(read_merge_config, NULL);
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}
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static const struct ll_merge_driver *find_ll_merge_driver(const char *merge_attr)
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{
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struct ll_merge_driver *fn;
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const char *name;
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int i;
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initialize_ll_merge();
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if (ATTR_TRUE(merge_attr))
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return &ll_merge_drv[LL_TEXT_MERGE];
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else if (ATTR_FALSE(merge_attr))
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return &ll_merge_drv[LL_BINARY_MERGE];
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else if (ATTR_UNSET(merge_attr)) {
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if (!default_ll_merge)
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return &ll_merge_drv[LL_TEXT_MERGE];
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else
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name = default_ll_merge;
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}
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else
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name = merge_attr;
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for (fn = ll_user_merge; fn; fn = fn->next)
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if (!strcmp(fn->name, name))
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return fn;
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for (i = 0; i < ARRAY_SIZE(ll_merge_drv); i++)
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if (!strcmp(ll_merge_drv[i].name, name))
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return &ll_merge_drv[i];
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/* default to the 3-way */
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return &ll_merge_drv[LL_TEXT_MERGE];
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}
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static const char *git_path_check_merge(const char *path)
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{
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static struct git_attr_check attr_merge_check;
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if (!attr_merge_check.attr)
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attr_merge_check.attr = git_attr("merge", 5);
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if (git_checkattr(path, 1, &attr_merge_check))
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return NULL;
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return attr_merge_check.value;
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}
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int ll_merge(mmbuffer_t *result_buf,
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const char *path,
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mmfile_t *ancestor,
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mmfile_t *ours, const char *our_label,
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mmfile_t *theirs, const char *their_label,
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int virtual_ancestor)
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{
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const char *ll_driver_name;
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const struct ll_merge_driver *driver;
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ll_driver_name = git_path_check_merge(path);
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driver = find_ll_merge_driver(ll_driver_name);
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if (virtual_ancestor && driver->recursive)
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driver = find_ll_merge_driver(driver->recursive);
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return driver->fn(driver, result_buf, path,
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ancestor,
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ours, our_label,
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theirs, their_label, virtual_ancestor);
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}
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