merge-blobs.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 #include "merge-blobs.h"
   7
   8 static int fill_mmfile_blob(mmfile_t *f, struct blob *obj)
   9 {
  10         void *buf;
  11         unsigned long size;
  12         enum object_type type;
  13
  14         buf = read_sha1_file(obj->object.sha1, &type, &size);
  15         if (!buf)
  16                 return -1;
  17         if (type != OBJ_BLOB)
  18                 return -1;
  19         f->ptr = buf;
  20         f->size = size;
  21         return 0;
  22 }
  23
  24 static void free_mmfile(mmfile_t *f)
  25 {
  26         free(f->ptr);
  27 }
  28
  29 static void *three_way_filemerge(const char *path, mmfile_t *base, mmfile_t *our, mmfile_t *their, unsigned long *size)
  30 {
  31         int merge_status;
  32         mmbuffer_t res;
  33
  34         /*
  35          * This function is only used by cmd_merge_tree, which
  36          * does not respect the merge.conflictstyle option.
  37          * There is no need to worry about a label for the
  38          * common ancestor.
  39          */
  40         merge_status = ll_merge(&res, path, base, NULL,
  41                                 our, ".our", their, ".their", NULL);
  42         if (merge_status < 0)
  43                 return NULL;
  44
  45         *size = res.size;
  46         return res.ptr;
  47 }
  48
  49 static int common_outf(void *priv_, mmbuffer_t *mb, int nbuf)
  50 {
  51         int i;
  52         mmfile_t *dst = priv_;
  53
  54         for (i = 0; i < nbuf; i++) {
  55                 memcpy(dst->ptr + dst->size, mb[i].ptr, mb[i].size);
  56                 dst->size += mb[i].size;
  57         }
  58         return 0;
  59 }
  60
  61 static int generate_common_file(mmfile_t *res, mmfile_t *f1, mmfile_t *f2)
  62 {
  63         unsigned long size = f1->size < f2->size ? f1->size : f2->size;
  64         void *ptr = xmalloc(size);
  65         xpparam_t xpp;
  66         xdemitconf_t xecfg;
  67         xdemitcb_t ecb;
  68
  69         memset(&xpp, 0, sizeof(xpp));
  70         xpp.flags = 0;
  71         memset(&xecfg, 0, sizeof(xecfg));
  72         xecfg.ctxlen = 3;
  73         xecfg.flags = XDL_EMIT_COMMON;
  74         ecb.outf = common_outf;
  75
  76         res->ptr = ptr;
  77         res->size = 0;
  78
  79         ecb.priv = res;
  80         return xdi_diff(f1, f2, &xpp, &xecfg, &ecb);
  81 }
  82
  83 void *merge_blobs(const char *path, struct blob *base, struct blob *our, struct blob *their, unsigned long *size)
  84 {
  85         void *res = NULL;
  86         mmfile_t f1, f2, common;
  87
  88         /*
  89          * Removed in either branch?
  90          *
  91          * NOTE! This depends on the caller having done the
  92          * proper warning about removing a file that got
  93          * modified in the other branch!
  94          */
  95         if (!our || !their) {
  96                 enum object_type type;
  97                 if (base)
  98                         return NULL;
  99                 if (!our)
 100                         our = their;
 101                 return read_sha1_file(our->object.sha1, &type, size);
 102         }
 103
 104         if (fill_mmfile_blob(&f1, our) < 0)
 105                 goto out_no_mmfile;
 106         if (fill_mmfile_blob(&f2, their) < 0)
 107                 goto out_free_f1;
 108
 109         if (base) {
 110                 if (fill_mmfile_blob(&common, base) < 0)
 111                         goto out_free_f2_f1;
 112         } else {
 113                 if (generate_common_file(&common, &f1, &f2) < 0)
 114                         goto out_free_f2_f1;
 115         }
 116         res = three_way_filemerge(path, &common, &f1, &f2, size);
 117         free_mmfile(&common);
 118 out_free_f2_f1:
 119         free_mmfile(&f2);
 120 out_free_f1:
 121         free_mmfile(&f1);
 122 out_no_mmfile:
 123         return res;
 124 }