Merge branch 'pb/submodule-doc-xref'
[git] / fsmonitor.c
1 #include "cache.h"
2 #include "config.h"
3 #include "dir.h"
4 #include "ewah/ewok.h"
5 #include "fsmonitor.h"
6 #include "run-command.h"
7 #include "strbuf.h"
8
9 #define INDEX_EXTENSION_VERSION (1)
10 #define HOOK_INTERFACE_VERSION  (1)
11
12 struct trace_key trace_fsmonitor = TRACE_KEY_INIT(FSMONITOR);
13
14 static void fsmonitor_ewah_callback(size_t pos, void *is)
15 {
16         struct index_state *istate = (struct index_state *)is;
17         struct cache_entry *ce;
18
19         if (pos >= istate->cache_nr)
20                 BUG("fsmonitor_dirty has more entries than the index (%"PRIuMAX" >= %u)",
21                     (uintmax_t)pos, istate->cache_nr);
22
23         ce = istate->cache[pos];
24         ce->ce_flags &= ~CE_FSMONITOR_VALID;
25 }
26
27 int read_fsmonitor_extension(struct index_state *istate, const void *data,
28         unsigned long sz)
29 {
30         const char *index = data;
31         uint32_t hdr_version;
32         uint32_t ewah_size;
33         struct ewah_bitmap *fsmonitor_dirty;
34         int ret;
35
36         if (sz < sizeof(uint32_t) + sizeof(uint64_t) + sizeof(uint32_t))
37                 return error("corrupt fsmonitor extension (too short)");
38
39         hdr_version = get_be32(index);
40         index += sizeof(uint32_t);
41         if (hdr_version != INDEX_EXTENSION_VERSION)
42                 return error("bad fsmonitor version %d", hdr_version);
43
44         istate->fsmonitor_last_update = get_be64(index);
45         index += sizeof(uint64_t);
46
47         ewah_size = get_be32(index);
48         index += sizeof(uint32_t);
49
50         fsmonitor_dirty = ewah_new();
51         ret = ewah_read_mmap(fsmonitor_dirty, index, ewah_size);
52         if (ret != ewah_size) {
53                 ewah_free(fsmonitor_dirty);
54                 return error("failed to parse ewah bitmap reading fsmonitor index extension");
55         }
56         istate->fsmonitor_dirty = fsmonitor_dirty;
57
58         if (!istate->split_index &&
59             istate->fsmonitor_dirty->bit_size > istate->cache_nr)
60                 BUG("fsmonitor_dirty has more entries than the index (%"PRIuMAX" > %u)",
61                     (uintmax_t)istate->fsmonitor_dirty->bit_size, istate->cache_nr);
62
63         trace_printf_key(&trace_fsmonitor, "read fsmonitor extension successful");
64         return 0;
65 }
66
67 void fill_fsmonitor_bitmap(struct index_state *istate)
68 {
69         unsigned int i, skipped = 0;
70         istate->fsmonitor_dirty = ewah_new();
71         for (i = 0; i < istate->cache_nr; i++) {
72                 if (istate->cache[i]->ce_flags & CE_REMOVE)
73                         skipped++;
74                 else if (!(istate->cache[i]->ce_flags & CE_FSMONITOR_VALID))
75                         ewah_set(istate->fsmonitor_dirty, i - skipped);
76         }
77 }
78
79 void write_fsmonitor_extension(struct strbuf *sb, struct index_state *istate)
80 {
81         uint32_t hdr_version;
82         uint64_t tm;
83         uint32_t ewah_start;
84         uint32_t ewah_size = 0;
85         int fixup = 0;
86
87         if (!istate->split_index &&
88             istate->fsmonitor_dirty->bit_size > istate->cache_nr)
89                 BUG("fsmonitor_dirty has more entries than the index (%"PRIuMAX" > %u)",
90                     (uintmax_t)istate->fsmonitor_dirty->bit_size, istate->cache_nr);
91
92         put_be32(&hdr_version, INDEX_EXTENSION_VERSION);
93         strbuf_add(sb, &hdr_version, sizeof(uint32_t));
94
95         put_be64(&tm, istate->fsmonitor_last_update);
96         strbuf_add(sb, &tm, sizeof(uint64_t));
97         fixup = sb->len;
98         strbuf_add(sb, &ewah_size, sizeof(uint32_t)); /* we'll fix this up later */
99
100         ewah_start = sb->len;
101         ewah_serialize_strbuf(istate->fsmonitor_dirty, sb);
102         ewah_free(istate->fsmonitor_dirty);
103         istate->fsmonitor_dirty = NULL;
104
105         /* fix up size field */
106         put_be32(&ewah_size, sb->len - ewah_start);
107         memcpy(sb->buf + fixup, &ewah_size, sizeof(uint32_t));
108
109         trace_printf_key(&trace_fsmonitor, "write fsmonitor extension successful");
110 }
111
112 /*
113  * Call the query-fsmonitor hook passing the time of the last saved results.
114  */
115 static int query_fsmonitor(int version, uint64_t last_update, struct strbuf *query_result)
116 {
117         struct child_process cp = CHILD_PROCESS_INIT;
118
119         if (!core_fsmonitor)
120                 return -1;
121
122         argv_array_push(&cp.args, core_fsmonitor);
123         argv_array_pushf(&cp.args, "%d", version);
124         argv_array_pushf(&cp.args, "%" PRIuMAX, (uintmax_t)last_update);
125         cp.use_shell = 1;
126         cp.dir = get_git_work_tree();
127
128         return capture_command(&cp, query_result, 1024);
129 }
130
131 static void fsmonitor_refresh_callback(struct index_state *istate, const char *name)
132 {
133         int pos = index_name_pos(istate, name, strlen(name));
134
135         if (pos >= 0) {
136                 struct cache_entry *ce = istate->cache[pos];
137                 ce->ce_flags &= ~CE_FSMONITOR_VALID;
138         }
139
140         /*
141          * Mark the untracked cache dirty even if it wasn't found in the index
142          * as it could be a new untracked file.
143          */
144         trace_printf_key(&trace_fsmonitor, "fsmonitor_refresh_callback '%s'", name);
145         untracked_cache_invalidate_path(istate, name, 0);
146 }
147
148 void refresh_fsmonitor(struct index_state *istate)
149 {
150         struct strbuf query_result = STRBUF_INIT;
151         int query_success = 0;
152         size_t bol; /* beginning of line */
153         uint64_t last_update;
154         char *buf;
155         unsigned int i;
156
157         if (!core_fsmonitor || istate->fsmonitor_has_run_once)
158                 return;
159         istate->fsmonitor_has_run_once = 1;
160
161         trace_printf_key(&trace_fsmonitor, "refresh fsmonitor");
162         /*
163          * This could be racy so save the date/time now and query_fsmonitor
164          * should be inclusive to ensure we don't miss potential changes.
165          */
166         last_update = getnanotime();
167
168         /*
169          * If we have a last update time, call query_fsmonitor for the set of
170          * changes since that time, else assume everything is possibly dirty
171          * and check it all.
172          */
173         if (istate->fsmonitor_last_update) {
174                 query_success = !query_fsmonitor(HOOK_INTERFACE_VERSION,
175                         istate->fsmonitor_last_update, &query_result);
176                 trace_performance_since(last_update, "fsmonitor process '%s'", core_fsmonitor);
177                 trace_printf_key(&trace_fsmonitor, "fsmonitor process '%s' returned %s",
178                         core_fsmonitor, query_success ? "success" : "failure");
179         }
180
181         /* a fsmonitor process can return '/' to indicate all entries are invalid */
182         if (query_success && query_result.buf[0] != '/') {
183                 /* Mark all entries returned by the monitor as dirty */
184                 buf = query_result.buf;
185                 bol = 0;
186                 for (i = 0; i < query_result.len; i++) {
187                         if (buf[i] != '\0')
188                                 continue;
189                         fsmonitor_refresh_callback(istate, buf + bol);
190                         bol = i + 1;
191                 }
192                 if (bol < query_result.len)
193                         fsmonitor_refresh_callback(istate, buf + bol);
194
195                 /* Now mark the untracked cache for fsmonitor usage */
196                 if (istate->untracked)
197                         istate->untracked->use_fsmonitor = 1;
198         } else {
199
200                 /* We only want to run the post index changed hook if we've actually changed entries, so keep track
201                  * if we actually changed entries or not */
202                 int is_cache_changed = 0;
203                 /* Mark all entries invalid */
204                 for (i = 0; i < istate->cache_nr; i++) {
205                         if (istate->cache[i]->ce_flags & CE_FSMONITOR_VALID) {
206                                 is_cache_changed = 1;
207                                 istate->cache[i]->ce_flags &= ~CE_FSMONITOR_VALID;
208                         }
209                 }
210
211                 /* If we're going to check every file, ensure we save the results */
212                 if (is_cache_changed)
213                         istate->cache_changed |= FSMONITOR_CHANGED;
214
215                 if (istate->untracked)
216                         istate->untracked->use_fsmonitor = 0;
217         }
218         strbuf_release(&query_result);
219
220         /* Now that we've updated istate, save the last_update time */
221         istate->fsmonitor_last_update = last_update;
222 }
223
224 void add_fsmonitor(struct index_state *istate)
225 {
226         unsigned int i;
227
228         if (!istate->fsmonitor_last_update) {
229                 trace_printf_key(&trace_fsmonitor, "add fsmonitor");
230                 istate->cache_changed |= FSMONITOR_CHANGED;
231                 istate->fsmonitor_last_update = getnanotime();
232
233                 /* reset the fsmonitor state */
234                 for (i = 0; i < istate->cache_nr; i++)
235                         istate->cache[i]->ce_flags &= ~CE_FSMONITOR_VALID;
236
237                 /* reset the untracked cache */
238                 if (istate->untracked) {
239                         add_untracked_cache(istate);
240                         istate->untracked->use_fsmonitor = 1;
241                 }
242
243                 /* Update the fsmonitor state */
244                 refresh_fsmonitor(istate);
245         }
246 }
247
248 void remove_fsmonitor(struct index_state *istate)
249 {
250         if (istate->fsmonitor_last_update) {
251                 trace_printf_key(&trace_fsmonitor, "remove fsmonitor");
252                 istate->cache_changed |= FSMONITOR_CHANGED;
253                 istate->fsmonitor_last_update = 0;
254         }
255 }
256
257 void tweak_fsmonitor(struct index_state *istate)
258 {
259         unsigned int i;
260         int fsmonitor_enabled = git_config_get_fsmonitor();
261
262         if (istate->fsmonitor_dirty) {
263                 if (fsmonitor_enabled) {
264                         /* Mark all entries valid */
265                         for (i = 0; i < istate->cache_nr; i++) {
266                                 istate->cache[i]->ce_flags |= CE_FSMONITOR_VALID;
267                         }
268
269                         /* Mark all previously saved entries as dirty */
270                         if (istate->fsmonitor_dirty->bit_size > istate->cache_nr)
271                                 BUG("fsmonitor_dirty has more entries than the index (%"PRIuMAX" > %u)",
272                                     (uintmax_t)istate->fsmonitor_dirty->bit_size, istate->cache_nr);
273                         ewah_each_bit(istate->fsmonitor_dirty, fsmonitor_ewah_callback, istate);
274
275                         refresh_fsmonitor(istate);
276                 }
277
278                 ewah_free(istate->fsmonitor_dirty);
279                 istate->fsmonitor_dirty = NULL;
280         }
281
282         switch (fsmonitor_enabled) {
283         case -1: /* keep: do nothing */
284                 break;
285         case 0: /* false */
286                 remove_fsmonitor(istate);
287                 break;
288         case 1: /* true */
289                 add_fsmonitor(istate);
290                 break;
291         default: /* unknown value: do nothing */
292                 break;
293         }
294 }