merge-file.c

   1 #include "cache.h"
   2 #include "run-command.h"
   3 #include "xdiff-interface.h"
   4 #include "blob.h"
   5
   6 static int fill_mmfile_blob(mmfile_t *f, struct blob *obj)
   7 {
   8         void *buf;
   9         unsigned long size;
  10         enum object_type type;
  11
  12         buf = read_sha1_file(obj->object.sha1, &type, &size);
  13         if (!buf)
  14                 return -1;
  15         if (type != OBJ_BLOB)
  16                 return -1;
  17         f->ptr = buf;
  18         f->size = size;
  19         return 0;
  20 }
  21
  22 static void free_mmfile(mmfile_t *f)
  23 {
  24         free(f->ptr);
  25 }
  26
  27 static void *three_way_filemerge(mmfile_t *base, mmfile_t *our, mmfile_t *their, unsigned long *size)
  28 {
  29         mmbuffer_t res;
  30         xpparam_t xpp;
  31         int merge_status;
  32
  33         memset(&xpp, 0, sizeof(xpp));
  34         merge_status = xdl_merge(base, our, ".our", their, ".their",
  35                 &xpp, XDL_MERGE_ZEALOUS, &res);
  36
  37         if (merge_status < 0)
  38                 return NULL;
  39
  40         *size = res.size;
  41         return res.ptr;
  42 }
  43
  44 static int common_outf(void *priv_, mmbuffer_t *mb, int nbuf)
  45 {
  46         int i;
  47         mmfile_t *dst = priv_;
  48
  49         for (i = 0; i < nbuf; i++) {
  50                 memcpy(dst->ptr + dst->size, mb[i].ptr, mb[i].size);
  51                 dst->size += mb[i].size;
  52         }
  53         return 0;
  54 }
  55
  56 static int generate_common_file(mmfile_t *res, mmfile_t *f1, mmfile_t *f2)
  57 {
  58         unsigned long size = f1->size < f2->size ? f1->size : f2->size;
  59         void *ptr = xmalloc(size);
  60         xpparam_t xpp;
  61         xdemitconf_t xecfg;
  62         xdemitcb_t ecb;
  63
  64         xpp.flags = XDF_NEED_MINIMAL;
  65         memset(&xecfg, 0, sizeof(xecfg));
  66         xecfg.ctxlen = 3;
  67         xecfg.flags = XDL_EMIT_COMMON;
  68         ecb.outf = common_outf;
  69
  70         res->ptr = ptr;
  71         res->size = 0;
  72
  73         ecb.priv = res;
  74         return xdi_diff(f1, f2, &xpp, &xecfg, &ecb);
  75 }
  76
  77 void *merge_file(struct blob *base, struct blob *our, struct blob *their, unsigned long *size)
  78 {
  79         void *res = NULL;
  80         mmfile_t f1, f2, common;
  81
  82         /*
  83          * Removed in either branch?
  84          *
  85          * NOTE! This depends on the caller having done the
  86          * proper warning about removing a file that got
  87          * modified in the other branch!
  88          */
  89         if (!our || !their) {
  90                 enum object_type type;
  91                 if (base)
  92                         return NULL;
  93                 if (!our)
  94                         our = their;
  95                 return read_sha1_file(our->object.sha1, &type, size);
  96         }
  97
  98         if (fill_mmfile_blob(&f1, our) < 0)
  99                 goto out_no_mmfile;
 100         if (fill_mmfile_blob(&f2, their) < 0)
 101                 goto out_free_f1;
 102
 103         if (base) {
 104                 if (fill_mmfile_blob(&common, base) < 0)
 105                         goto out_free_f2_f1;
 106         } else {
 107                 if (generate_common_file(&common, &f1, &f2) < 0)
 108                         goto out_free_f2_f1;
 109         }
 110         res = three_way_filemerge(&common, &f1, &f2, size);
 111         free_mmfile(&common);
 112 out_free_f2_f1:
 113         free_mmfile(&f2);
 114 out_free_f1:
 115         free_mmfile(&f1);
 116 out_no_mmfile:
 117         return res;
 118 }