git-svn: allow dcommit for those who only fetch from SVM with useSvmProps
[git] / 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         char type[20];
11
12         buf = read_sha1_file(obj->object.sha1, type, &size);
13         if (!buf)
14                 return -1;
15         if (strcmp(type, blob_type))
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         xecfg.ctxlen = 3;
66         xecfg.flags = XDL_EMIT_COMMON;
67         ecb.outf = common_outf;
68
69         res->ptr = ptr;
70         res->size = 0;
71
72         ecb.priv = res;
73         return xdl_diff(f1, f2, &xpp, &xecfg, &ecb);
74 }
75
76 void *merge_file(struct blob *base, struct blob *our, struct blob *their, unsigned long *size)
77 {
78         void *res = NULL;
79         mmfile_t f1, f2, common;
80
81         /*
82          * Removed in either branch?
83          *
84          * NOTE! This depends on the caller having done the
85          * proper warning about removing a file that got
86          * modified in the other branch!
87          */
88         if (!our || !their) {
89                 char type[20];
90                 if (base)
91                         return NULL;
92                 if (!our)
93                         our = their;
94                 return read_sha1_file(our->object.sha1, type, size);
95         }
96
97         if (fill_mmfile_blob(&f1, our) < 0)
98                 goto out_no_mmfile;
99         if (fill_mmfile_blob(&f2, their) < 0)
100                 goto out_free_f1;
101
102         if (base) {
103                 if (fill_mmfile_blob(&common, base) < 0)
104                         goto out_free_f2_f1;
105         } else {
106                 if (generate_common_file(&common, &f1, &f2) < 0)
107                         goto out_free_f2_f1;
108         }
109         res = three_way_filemerge(&common, &f1, &f2, size);
110         free_mmfile(&common);
111 out_free_f2_f1:
112         free_mmfile(&f2);
113 out_free_f1:
114         free_mmfile(&f1);
115 out_no_mmfile:
116         return res;
117 }