+#include "cache.h"
+#include "config.h"
+#include "dir.h"
+#include "ewah/ewok.h"
+#include "fsmonitor.h"
+#include "run-command.h"
+#include "strbuf.h"
+
+#define INDEX_EXTENSION_VERSION (1)
+#define HOOK_INTERFACE_VERSION (1)
+
+struct trace_key trace_fsmonitor = TRACE_KEY_INIT(FSMONITOR);
+
+static void fsmonitor_ewah_callback(size_t pos, void *is)
+{
+ struct index_state *istate = (struct index_state *)is;
+ struct cache_entry *ce = istate->cache[pos];
+
+ ce->ce_flags &= ~CE_FSMONITOR_VALID;
+}
+
+int read_fsmonitor_extension(struct index_state *istate, const void *data,
+ unsigned long sz)
+{
+ const char *index = data;
+ uint32_t hdr_version;
+ uint32_t ewah_size;
+ struct ewah_bitmap *fsmonitor_dirty;
+ int i;
+ int ret;
+
+ if (sz < sizeof(uint32_t) + sizeof(uint64_t) + 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)
+ return error("bad fsmonitor version %d", hdr_version);
+
+ istate->fsmonitor_last_update = get_be64(index);
+ index += sizeof(uint64_t);
+
+ ewah_size = get_be32(index);
+ index += sizeof(uint32_t);
+
+ fsmonitor_dirty = ewah_new();
+ ret = ewah_read_mmap(fsmonitor_dirty, index, ewah_size);
+ if (ret != ewah_size) {
+ ewah_free(fsmonitor_dirty);
+ return error("failed to parse ewah bitmap reading fsmonitor index extension");
+ }
+
+ if (git_config_get_fsmonitor()) {
+ /* Mark all entries valid */
+ for (i = 0; i < istate->cache_nr; i++)
+ istate->cache[i]->ce_flags |= CE_FSMONITOR_VALID;
+
+ /* Mark all previously saved entries as dirty */
+ ewah_each_bit(fsmonitor_dirty, fsmonitor_ewah_callback, istate);
+
+ /* Now mark the untracked cache for fsmonitor usage */
+ if (istate->untracked)
+ istate->untracked->use_fsmonitor = 1;
+ }
+ ewah_free(fsmonitor_dirty);
+
+ trace_printf_key(&trace_fsmonitor, "read fsmonitor extension successful");
+ return 0;
+}
+
+void write_fsmonitor_extension(struct strbuf *sb, struct index_state *istate)
+{
+ uint32_t hdr_version;
+ uint64_t tm;
+ struct ewah_bitmap *bitmap;
+ int i;
+ uint32_t ewah_start;
+ uint32_t ewah_size = 0;
+ int fixup = 0;
+
+ put_be32(&hdr_version, INDEX_EXTENSION_VERSION);
+ strbuf_add(sb, &hdr_version, sizeof(uint32_t));
+
+ put_be64(&tm, istate->fsmonitor_last_update);
+ strbuf_add(sb, &tm, sizeof(uint64_t));
+ fixup = sb->len;
+ strbuf_add(sb, &ewah_size, sizeof(uint32_t)); /* we'll fix this up later */
+
+ ewah_start = sb->len;
+ bitmap = ewah_new();
+ for (i = 0; i < istate->cache_nr; i++)
+ if (!(istate->cache[i]->ce_flags & CE_FSMONITOR_VALID))
+ ewah_set(bitmap, i);
+ ewah_serialize_strbuf(bitmap, sb);
+ ewah_free(bitmap);
+
+ /* fix up size field */
+ put_be32(&ewah_size, sb->len - ewah_start);
+ memcpy(sb->buf + fixup, &ewah_size, sizeof(uint32_t));
+
+ trace_printf_key(&trace_fsmonitor, "write fsmonitor extension successful");
+}
+
+/*
+ * Call the query-fsmonitor hook passing the time of the last saved results.
+ */
+static int query_fsmonitor(int version, uint64_t last_update, struct strbuf *query_result)
+{
+ struct child_process cp = CHILD_PROCESS_INIT;
+ char ver[64];
+ char date[64];
+ const char *argv[4];
+
+ if (!(argv[0] = core_fsmonitor))
+ return -1;
+
+ snprintf(ver, sizeof(version), "%d", version);
+ snprintf(date, sizeof(date), "%" PRIuMAX, (uintmax_t)last_update);
+ argv[1] = ver;
+ argv[2] = date;
+ argv[3] = NULL;
+ cp.argv = argv;
+ cp.use_shell = 1;
+
+ return capture_command(&cp, query_result, 1024);
+}
+
+static void fsmonitor_refresh_callback(struct index_state *istate, const char *name)
+{
+ int pos = index_name_pos(istate, name, strlen(name));
+
+ if (pos >= 0) {
+ struct cache_entry *ce = istate->cache[pos];
+ ce->ce_flags &= ~CE_FSMONITOR_VALID;
+ }
+
+ /*
+ * Mark the untracked cache dirty even if it wasn't found in the index
+ * as it could be a new untracked file.
+ */
+ trace_printf_key(&trace_fsmonitor, "fsmonitor_refresh_callback '%s'", name);
+ untracked_cache_invalidate_path(istate, name);
+}
+
+void refresh_fsmonitor(struct index_state *istate)
+{
+ static int has_run_once = 0;
+ struct strbuf query_result = STRBUF_INIT;
+ int query_success = 0;
+ size_t bol; /* beginning of line */
+ uint64_t last_update;
+ char *buf;
+ int i;
+
+ if (!core_fsmonitor || has_run_once)
+ return;
+ has_run_once = 1;
+
+ trace_printf_key(&trace_fsmonitor, "refresh fsmonitor");
+ /*
+ * This could be racy so save the date/time now and query_fsmonitor
+ * should be inclusive to ensure we don't miss potential changes.
+ */
+ last_update = getnanotime();
+
+ /*
+ * If we have a last update time, call query_fsmonitor for the set of
+ * changes since that time, else assume everything is possibly dirty
+ * and check it all.
+ */
+ if (istate->fsmonitor_last_update) {
+ query_success = !query_fsmonitor(HOOK_INTERFACE_VERSION,
+ istate->fsmonitor_last_update, &query_result);
+ trace_performance_since(last_update, "fsmonitor process '%s'", core_fsmonitor);
+ trace_printf_key(&trace_fsmonitor, "fsmonitor process '%s' returned %s",
+ core_fsmonitor, query_success ? "success" : "failure");
+ }
+
+ /* a fsmonitor process can return '/' to indicate all entries are invalid */
+ if (query_success && query_result.buf[0] != '/') {
+ /* Mark all entries returned by the monitor as dirty */
+ buf = query_result.buf;
+ bol = 0;
+ for (i = 0; i < query_result.len; i++) {
+ if (buf[i] != '\0')
+ continue;
+ fsmonitor_refresh_callback(istate, buf + bol);
+ bol = i + 1;
+ }
+ if (bol < query_result.len)
+ fsmonitor_refresh_callback(istate, buf + bol);
+ } else {
+ /* Mark all entries invalid */
+ for (i = 0; i < istate->cache_nr; i++)
+ istate->cache[i]->ce_flags &= ~CE_FSMONITOR_VALID;
+
+ if (istate->untracked)
+ istate->untracked->use_fsmonitor = 0;
+ }
+ strbuf_release(&query_result);
+
+ /* Now that we've updated istate, save the last_update time */
+ istate->fsmonitor_last_update = last_update;
+}
+
+void add_fsmonitor(struct index_state *istate)
+{
+ int i;
+
+ if (!istate->fsmonitor_last_update) {
+ trace_printf_key(&trace_fsmonitor, "add fsmonitor");
+ istate->cache_changed |= FSMONITOR_CHANGED;
+ istate->fsmonitor_last_update = getnanotime();
+
+ /* reset the fsmonitor state */
+ for (i = 0; i < istate->cache_nr; i++)
+ istate->cache[i]->ce_flags &= ~CE_FSMONITOR_VALID;
+
+ /* reset the untracked cache */
+ if (istate->untracked) {
+ add_untracked_cache(istate);
+ istate->untracked->use_fsmonitor = 1;
+ }
+
+ /* Update the fsmonitor state */
+ refresh_fsmonitor(istate);
+ }
+}
+
+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;
+ }
+}
+
+void tweak_fsmonitor(struct index_state *istate)
+{
+ switch (git_config_get_fsmonitor()) {
+ case -1: /* keep: do nothing */
+ break;
+ case 0: /* false */
+ remove_fsmonitor(istate);
+ break;
+ case 1: /* true */
+ add_fsmonitor(istate);
+ break;
+ default: /* unknown value: do nothing */
+ break;
+ }
+}