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                 free(buf);
  19                 return -1;
  20         }
  21         f->ptr = buf;
  22         f->size = size;
  23         return 0;
  24 }
  25
  26 static void free_mmfile(mmfile_t *f)
  27 {
  28         free(f->ptr);
  29 }
  30
  31 static void *three_way_filemerge(const char *path, mmfile_t *base, mmfile_t *our, mmfile_t *their, unsigned long *size)
  32 {
  33         int merge_status;
  34         mmbuffer_t res;
  35
  36         /*
  37          * This function is only used by cmd_merge_tree, which
  38          * does not respect the merge.conflictstyle option.
  39          * There is no need to worry about a label for the
  40          * common ancestor.
  41          */
  42         merge_status = ll_merge(&res, path, base, NULL,
  43                                 our, ".our", their, ".their", NULL);
  44         if (merge_status < 0)
  45                 return NULL;
  46
  47         *size = res.size;
  48         return res.ptr;
  49 }
  50
  51 static int common_outf(void *priv_, mmbuffer_t *mb, int nbuf)
  52 {
  53         int i;
  54         mmfile_t *dst = priv_;
  55
  56         for (i = 0; i < nbuf; i++) {
  57                 memcpy(dst->ptr + dst->size, mb[i].ptr, mb[i].size);
  58                 dst->size += mb[i].size;
  59         }
  60         return 0;
  61 }
  62
  63 static int generate_common_file(mmfile_t *res, mmfile_t *f1, mmfile_t *f2)
  64 {
  65         unsigned long size = f1->size < f2->size ? f1->size : f2->size;
  66         void *ptr = xmalloc(size);
  67         xpparam_t xpp;
  68         xdemitconf_t xecfg;
  69         xdemitcb_t ecb;
  70
  71         memset(&xpp, 0, sizeof(xpp));
  72         xpp.flags = 0;
  73         memset(&xecfg, 0, sizeof(xecfg));
  74         xecfg.ctxlen = 3;
  75         xecfg.flags = XDL_EMIT_COMMON;
  76         ecb.outf = common_outf;
  77
  78         res->ptr = ptr;
  79         res->size = 0;
  80
  81         ecb.priv = res;
  82         return xdi_diff(f1, f2, &xpp, &xecfg, &ecb);
  83 }
  84
  85 void *merge_blobs(const char *path, struct blob *base, struct blob *our, struct blob *their, unsigned long *size)
  86 {
  87         void *res = NULL;
  88         mmfile_t f1, f2, common;
  89
  90         /*
  91          * Removed in either branch?
  92          *
  93          * NOTE! This depends on the caller having done the
  94          * proper warning about removing a file that got
  95          * modified in the other branch!
  96          */
  97         if (!our || !their) {
  98                 enum object_type type;
  99                 if (base)
 100                         return NULL;
 101                 if (!our)
 102                         our = their;
 103                 return read_sha1_file(our->object.sha1, &type, size);
 104         }
 105
 106         if (fill_mmfile_blob(&f1, our) < 0)
 107                 goto out_no_mmfile;
 108         if (fill_mmfile_blob(&f2, their) < 0)
 109                 goto out_free_f1;
 110
 111         if (base) {
 112                 if (fill_mmfile_blob(&common, base) < 0)
 113                         goto out_free_f2_f1;
 114         } else {
 115                 if (generate_common_file(&common, &f1, &f2) < 0)
 116                         goto out_free_f2_f1;
 117         }
 118         res = three_way_filemerge(path, &common, &f1, &f2, size);
 119         free_mmfile(&common);
 120 out_free_f2_f1:
 121         free_mmfile(&f2);
 122 out_free_f1:
 123         free_mmfile(&f1);
 124 out_no_mmfile:
 125         return res;
 126 }