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fsmonitor: change last update timestamp on the index_state to opaque token

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Some file system monitors might not use or take a timestamp for processing
and in the case of watchman could have race conditions with using a
timestamp. Watchman uses something called a clockid that is used for race
free queries to it. The clockid for watchman is simply a string.

Change the fsmonitor_last_update from being a uint64_t to a char pointer
so that any arbitrary data can be stored in it and passed back to the
fsmonitor.

Signed-off-by: Kevin Willford <Kevin.Willford@microsoft.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
This commit is contained in:
Kevin Willford 2020-01-07 19:04:28 +00:00 committed by Junio C Hamano
parent d0654dc308
commit 56c6910028
3 changed files with 34 additions and 19 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

2
cache.h
View File

@ -324,7 +324,7 @@ struct index_state {
struct hashmap dir_hash;
struct object_id oid;
struct untracked_cache *untracked;
uint64_t fsmonitor_last_update;
char *fsmonitor_last_update;
struct ewah_bitmap *fsmonitor_dirty;
struct mem_pool *ce_mem_pool;
struct progress *progress;

49
fsmonitor.c
View File

@ -6,8 +6,9 @@
#include "run-command.h"
#include "strbuf.h"
#define INDEX_EXTENSION_VERSION (1)
#define HOOK_INTERFACE_VERSION (1)
#define INDEX_EXTENSION_VERSION1 (1)
#define INDEX_EXTENSION_VERSION2 (2)
#define HOOK_INTERFACE_VERSION (1)
struct trace_key trace_fsmonitor = TRACE_KEY_INIT(FSMONITOR);
@ -32,17 +33,26 @@ int read_fsmonitor_extension(struct index_state *istate, const void *data,
uint32_t ewah_size;
struct ewah_bitmap *fsmonitor_dirty;
int ret;
uint64_t timestamp;
struct strbuf last_update = STRBUF_INIT;
if (sz < sizeof(uint32_t) + sizeof(uint64_t) + sizeof(uint32_t))
if (sz < sizeof(uint32_t) + 1 + sizeof(uint32_t))
return error("corrupt fsmonitor extension (too short)");
hdr_version = get_be32(index);
index += sizeof(uint32_t);
if (hdr_version != INDEX_EXTENSION_VERSION)
if (hdr_version == INDEX_EXTENSION_VERSION1) {
timestamp = get_be64(index);
strbuf_addf(&last_update, "%"PRIu64"", timestamp);
index += sizeof(uint64_t);
} else if (hdr_version == INDEX_EXTENSION_VERSION2) {
strbuf_addstr(&last_update, index);
index += last_update.len + 1;
} else {
return error("bad fsmonitor version %d", hdr_version);
}
istate->fsmonitor_last_update = get_be64(index);
index += sizeof(uint64_t);
istate->fsmonitor_last_update = strbuf_detach(&last_update, NULL);
ewah_size = get_be32(index);
index += sizeof(uint32_t);
@ -79,7 +89,6 @@ void fill_fsmonitor_bitmap(struct index_state *istate)
void write_fsmonitor_extension(struct strbuf *sb, struct index_state *istate)
{
uint32_t hdr_version;
uint64_t tm;
uint32_t ewah_start;
uint32_t ewah_size = 0;
int fixup = 0;
@ -89,11 +98,12 @@ void write_fsmonitor_extension(struct strbuf *sb, struct index_state *istate)
BUG("fsmonitor_dirty has more entries than the index (%"PRIuMAX" > %u)",
(uintmax_t)istate->fsmonitor_dirty->bit_size, istate->cache_nr);
put_be32(&hdr_version, INDEX_EXTENSION_VERSION);
put_be32(&hdr_version, INDEX_EXTENSION_VERSION2);
strbuf_add(sb, &hdr_version, sizeof(uint32_t));
put_be64(&tm, istate->fsmonitor_last_update);
strbuf_add(sb, &tm, sizeof(uint64_t));
strbuf_addstr(sb, istate->fsmonitor_last_update);
strbuf_addch(sb, 0); /* Want to keep a NUL */
fixup = sb->len;
strbuf_add(sb, &ewah_size, sizeof(uint32_t)); /* we'll fix this up later */
@ -110,9 +120,9 @@ void write_fsmonitor_extension(struct strbuf *sb, struct index_state *istate)
}
/*
* Call the query-fsmonitor hook passing the time of the last saved results.
* Call the query-fsmonitor hook passing the last update token of the saved results.
*/
static int query_fsmonitor(int version, uint64_t last_update, struct strbuf *query_result)
static int query_fsmonitor(int version, const char *last_update, struct strbuf *query_result)
{
struct child_process cp = CHILD_PROCESS_INIT;
@ -121,7 +131,7 @@ static int query_fsmonitor(int version, uint64_t last_update, struct strbuf *que
argv_array_push(&cp.args, core_fsmonitor);
argv_array_pushf(&cp.args, "%d", version);
argv_array_pushf(&cp.args, "%" PRIuMAX, (uintmax_t)last_update);
argv_array_pushf(&cp.args, "%s", last_update);
cp.use_shell = 1;
cp.dir = get_git_work_tree();
@ -151,6 +161,7 @@ void refresh_fsmonitor(struct index_state *istate)
int query_success = 0;
size_t bol; /* beginning of line */
uint64_t last_update;
struct strbuf last_update_token = STRBUF_INIT;
char *buf;
unsigned int i;
@ -164,6 +175,7 @@ void refresh_fsmonitor(struct index_state *istate)
* should be inclusive to ensure we don't miss potential changes.
*/
last_update = getnanotime();
strbuf_addf(&last_update_token, "%"PRIu64"", last_update);
/*
* If we have a last update time, call query_fsmonitor for the set of
@ -217,18 +229,21 @@ void refresh_fsmonitor(struct index_state *istate)
}
strbuf_release(&query_result);
/* Now that we've updated istate, save the last_update time */
istate->fsmonitor_last_update = last_update;
/* Now that we've updated istate, save the last_update_token */
FREE_AND_NULL(istate->fsmonitor_last_update);
istate->fsmonitor_last_update = strbuf_detach(&last_update_token, NULL);
}
void add_fsmonitor(struct index_state *istate)
{
unsigned int i;
struct strbuf last_update = STRBUF_INIT;
if (!istate->fsmonitor_last_update) {
trace_printf_key(&trace_fsmonitor, "add fsmonitor");
istate->cache_changed |= FSMONITOR_CHANGED;
istate->fsmonitor_last_update = getnanotime();
strbuf_addf(&last_update, "%"PRIu64"", getnanotime());
istate->fsmonitor_last_update = strbuf_detach(&last_update, NULL);
/* reset the fsmonitor state */
for (i = 0; i < istate->cache_nr; i++)
@ -250,7 +265,7 @@ void remove_fsmonitor(struct index_state *istate)
if (istate->fsmonitor_last_update) {
trace_printf_key(&trace_fsmonitor, "remove fsmonitor");
istate->cache_changed |= FSMONITOR_CHANGED;
istate->fsmonitor_last_update = 0;
FREE_AND_NULL(istate->fsmonitor_last_update);
}
}

2
t/helper/test-dump-fsmonitor.c
View File

@ -13,7 +13,7 @@ int cmd__dump_fsmonitor(int ac, const char **av)
printf("no fsmonitor\n");
return 0;
}
printf("fsmonitor last update %"PRIuMAX"\n", (uintmax_t)istate->fsmonitor_last_update);
printf("fsmonitor last update %s\n", istate->fsmonitor_last_update);
for (i = 0; i < istate->cache_nr; i++)
printf((istate->cache[i]->ce_flags & CE_FSMONITOR_VALID) ? "+" : "-");