builtin/show: do not prune by pathspec
[git/mjg.git] / csum-file.c
blobbf82ad8f9f5522a2f666aadf94f995b9b2ac1b9b
1 /*
2 * csum-file.c
4 * Copyright (C) 2005 Linus Torvalds
6 * Simple file write infrastructure for writing SHA1-summed
7 * files. Useful when you write a file that you want to be
8 * able to verify hasn't been messed with afterwards.
9 */
11 #define USE_THE_REPOSITORY_VARIABLE
13 #include "git-compat-util.h"
14 #include "progress.h"
15 #include "csum-file.h"
16 #include "hash.h"
18 static void verify_buffer_or_die(struct hashfile *f,
19 const void *buf,
20 unsigned int count)
22 ssize_t ret = read_in_full(f->check_fd, f->check_buffer, count);
24 if (ret < 0)
25 die_errno("%s: sha1 file read error", f->name);
26 if (ret != count)
27 die("%s: sha1 file truncated", f->name);
28 if (memcmp(buf, f->check_buffer, count))
29 die("sha1 file '%s' validation error", f->name);
32 static void flush(struct hashfile *f, const void *buf, unsigned int count)
34 if (0 <= f->check_fd && count)
35 verify_buffer_or_die(f, buf, count);
37 if (write_in_full(f->fd, buf, count) < 0) {
38 if (errno == ENOSPC)
39 die("sha1 file '%s' write error. Out of diskspace", f->name);
40 die_errno("sha1 file '%s' write error", f->name);
43 f->total += count;
44 display_throughput(f->tp, f->total);
47 void hashflush(struct hashfile *f)
49 unsigned offset = f->offset;
51 if (offset) {
52 if (!f->skip_hash)
53 the_hash_algo->update_fn(&f->ctx, f->buffer, offset);
54 flush(f, f->buffer, offset);
55 f->offset = 0;
59 void free_hashfile(struct hashfile *f)
61 free(f->buffer);
62 free(f->check_buffer);
63 free(f);
66 int finalize_hashfile(struct hashfile *f, unsigned char *result,
67 enum fsync_component component, unsigned int flags)
69 int fd;
71 hashflush(f);
73 if (f->skip_hash)
74 hashclr(f->buffer, the_repository->hash_algo);
75 else
76 the_hash_algo->final_fn(f->buffer, &f->ctx);
78 if (result)
79 hashcpy(result, f->buffer, the_repository->hash_algo);
80 if (flags & CSUM_HASH_IN_STREAM)
81 flush(f, f->buffer, the_hash_algo->rawsz);
82 if (flags & CSUM_FSYNC)
83 fsync_component_or_die(component, f->fd, f->name);
84 if (flags & CSUM_CLOSE) {
85 if (close(f->fd))
86 die_errno("%s: sha1 file error on close", f->name);
87 fd = 0;
88 } else
89 fd = f->fd;
90 if (0 <= f->check_fd) {
91 char discard;
92 int cnt = read_in_full(f->check_fd, &discard, 1);
93 if (cnt < 0)
94 die_errno("%s: error when reading the tail of sha1 file",
95 f->name);
96 if (cnt)
97 die("%s: sha1 file has trailing garbage", f->name);
98 if (close(f->check_fd))
99 die_errno("%s: sha1 file error on close", f->name);
101 free_hashfile(f);
102 return fd;
105 void discard_hashfile(struct hashfile *f)
107 if (0 <= f->check_fd)
108 close(f->check_fd);
109 if (0 <= f->fd)
110 close(f->fd);
111 free_hashfile(f);
114 void hashwrite(struct hashfile *f, const void *buf, unsigned int count)
116 while (count) {
117 unsigned left = f->buffer_len - f->offset;
118 unsigned nr = count > left ? left : count;
120 if (f->do_crc)
121 f->crc32 = crc32(f->crc32, buf, nr);
123 if (nr == f->buffer_len) {
125 * Flush a full batch worth of data directly
126 * from the input, skipping the memcpy() to
127 * the hashfile's buffer. In this block,
128 * f->offset is necessarily zero.
130 if (!f->skip_hash)
131 the_hash_algo->update_fn(&f->ctx, buf, nr);
132 flush(f, buf, nr);
133 } else {
135 * Copy to the hashfile's buffer, flushing only
136 * if it became full.
138 memcpy(f->buffer + f->offset, buf, nr);
139 f->offset += nr;
140 left -= nr;
141 if (!left)
142 hashflush(f);
145 count -= nr;
146 buf = (char *) buf + nr;
150 struct hashfile *hashfd_check(const char *name)
152 int sink, check;
153 struct hashfile *f;
155 sink = xopen("/dev/null", O_WRONLY);
156 check = xopen(name, O_RDONLY);
157 f = hashfd(sink, name);
158 f->check_fd = check;
159 f->check_buffer = xmalloc(f->buffer_len);
161 return f;
164 static struct hashfile *hashfd_internal(int fd, const char *name,
165 struct progress *tp,
166 size_t buffer_len)
168 struct hashfile *f = xmalloc(sizeof(*f));
169 f->fd = fd;
170 f->check_fd = -1;
171 f->offset = 0;
172 f->total = 0;
173 f->tp = tp;
174 f->name = name;
175 f->do_crc = 0;
176 f->skip_hash = 0;
177 the_hash_algo->init_fn(&f->ctx);
179 f->buffer_len = buffer_len;
180 f->buffer = xmalloc(buffer_len);
181 f->check_buffer = NULL;
183 return f;
186 struct hashfile *hashfd(int fd, const char *name)
189 * Since we are not going to use a progress meter to
190 * measure the rate of data passing through this hashfile,
191 * use a larger buffer size to reduce fsync() calls.
193 return hashfd_internal(fd, name, NULL, 128 * 1024);
196 struct hashfile *hashfd_throughput(int fd, const char *name, struct progress *tp)
199 * Since we are expecting to report progress of the
200 * write into this hashfile, use a smaller buffer
201 * size so the progress indicators arrive at a more
202 * frequent rate.
204 return hashfd_internal(fd, name, tp, 8 * 1024);
207 void hashfile_checkpoint(struct hashfile *f, struct hashfile_checkpoint *checkpoint)
209 hashflush(f);
210 checkpoint->offset = f->total;
211 the_hash_algo->clone_fn(&checkpoint->ctx, &f->ctx);
214 int hashfile_truncate(struct hashfile *f, struct hashfile_checkpoint *checkpoint)
216 off_t offset = checkpoint->offset;
218 if (ftruncate(f->fd, offset) ||
219 lseek(f->fd, offset, SEEK_SET) != offset)
220 return -1;
221 f->total = offset;
222 the_hash_algo->clone_fn(&f->ctx, &checkpoint->ctx);
223 f->offset = 0; /* hashflush() was called in checkpoint */
224 return 0;
227 void crc32_begin(struct hashfile *f)
229 f->crc32 = crc32(0, NULL, 0);
230 f->do_crc = 1;
233 uint32_t crc32_end(struct hashfile *f)
235 f->do_crc = 0;
236 return f->crc32;
239 int hashfile_checksum_valid(const unsigned char *data, size_t total_len)
241 unsigned char got[GIT_MAX_RAWSZ];
242 git_hash_ctx ctx;
243 size_t data_len = total_len - the_hash_algo->rawsz;
245 if (total_len < the_hash_algo->rawsz)
246 return 0; /* say "too short"? */
248 the_hash_algo->init_fn(&ctx);
249 the_hash_algo->update_fn(&ctx, data, data_len);
250 the_hash_algo->final_fn(got, &ctx);
252 return hasheq(got, data + data_len, the_repository->hash_algo);