merge-file.c

   1 #include "cache.h"
   2 #include "run-command.h"
   3 #include "xdiff-interface.h"
   4 #include "ll-merge.h"
   5 #include "blob.h"
   6
   7 static int fill_mmfile_blob(mmfile_t *f, struct blob *obj)
   8 {
   9         void *buf;
  10         unsigned long size;
  11         enum object_type type;
  12
  13         buf = read_sha1_file(obj->object.sha1, &type, &size);
  14         if (!buf)
  15                 return -1;
  16         if (type != OBJ_BLOB)
  17                 return -1;
  18         f->ptr = buf;
  19         f->size = size;
  20         return 0;
  21 }
  22
  23 static void free_mmfile(mmfile_t *f)
  24 {
  25         free(f->ptr);
  26 }
  27
  28 static void *three_way_filemerge(const char *path, mmfile_t *base, mmfile_t *our, mmfile_t *their, unsigned long *size)
  29 {
  30         int merge_status;
  31         mmbuffer_t res;
  32
  33         /*
  34          * This function is only used by cmd_merge_tree, which
  35          * does not respect the merge.conflictstyle option.
  36          * There is no need to worry about a label for the
  37          * common ancestor.
  38          */
  39         merge_status = ll_merge(&res, path, base, NULL,
  40                                 our, ".our", their, ".their", NULL);
  41         if (merge_status < 0)
  42                 return NULL;
  43
  44         *size = res.size;
  45         return res.ptr;
  46 }
  47
  48 static int common_outf(void *priv_, mmbuffer_t *mb, int nbuf)
  49 {
  50         int i;
  51         mmfile_t *dst = priv_;
  52
  53         for (i = 0; i < nbuf; i++) {
  54                 memcpy(dst->ptr + dst->size, mb[i].ptr, mb[i].size);
  55                 dst->size += mb[i].size;
  56         }
  57         return 0;
  58 }
  59
  60 static int generate_common_file(mmfile_t *res, mmfile_t *f1, mmfile_t *f2)
  61 {
  62         unsigned long size = f1->size < f2->size ? f1->size : f2->size;
  63         void *ptr = xmalloc(size);
  64         xpparam_t xpp;
  65         xdemitconf_t xecfg;
  66         xdemitcb_t ecb;
  67
  68         memset(&xpp, 0, sizeof(xpp));
  69         xpp.flags = 0;
  70         memset(&xecfg, 0, sizeof(xecfg));
  71         xecfg.ctxlen = 3;
  72         xecfg.flags = XDL_EMIT_COMMON;
  73         ecb.outf = common_outf;
  74
  75         res->ptr = ptr;
  76         res->size = 0;
  77
  78         ecb.priv = res;
  79         return xdi_diff(f1, f2, &xpp, &xecfg, &ecb);
  80 }
  81
  82 void *merge_file(const char *path, struct blob *base, struct blob *our, struct blob *their, unsigned long *size)
  83 {
  84         void *res = NULL;
  85         mmfile_t f1, f2, common;
  86
  87         /*
  88          * Removed in either branch?
  89          *
  90          * NOTE! This depends on the caller having done the
  91          * proper warning about removing a file that got
  92          * modified in the other branch!
  93          */
  94         if (!our || !their) {
  95                 enum object_type type;
  96                 if (base)
  97                         return NULL;
  98                 if (!our)
  99                         our = their;
 100                 return read_sha1_file(our->object.sha1, &type, size);
 101         }
 102
 103         if (fill_mmfile_blob(&f1, our) < 0)
 104                 goto out_no_mmfile;
 105         if (fill_mmfile_blob(&f2, their) < 0)
 106                 goto out_free_f1;
 107
 108         if (base) {
 109                 if (fill_mmfile_blob(&common, base) < 0)
 110                         goto out_free_f2_f1;
 111         } else {
 112                 if (generate_common_file(&common, &f1, &f2) < 0)
 113                         goto out_free_f2_f1;
 114         }
 115         res = three_way_filemerge(path, &common, &f1, &f2, size);
 116         free_mmfile(&common);
 117 out_free_f2_f1:
 118         free_mmfile(&f2);
 119 out_free_f1:
 120         free_mmfile(&f1);
 121 out_no_mmfile:
 122         return res;
 123 }