Re: [PATCH v12 10/20] watchman: support watchman to reduce index refresh cost

From: Nguyễn Thái Ngọc Duy <redacted>

The previous patch has the logic to clear bits in 'WAMA' bitmap. This
patch has logic to set bits as told by watchman. The missing bit,
_using_ these bits, are not here yet.

A lot of this code is written by David Turner originally, mostly from
[1]. I'm just copying and polishing it a bit.

[1] http://article.gmane.org/gmane.comp.version-control.git/248006

Signed-off-by: Nguyễn Thái Ngọc Duy <redacted>
Signed-off-by: David Turner <redacted>
---
 Makefile           |  12 +++++
 cache.h            |   1 +
 config.c           |   5 ++
 configure.ac       |   8 ++++
 environment.c      |   3 ++
 watchman-support.c | 135 +++++++++++++++++++++++++++++++++++++++++++++++++++++
 watchman-support.h |   7 +++
 7 files changed, 171 insertions(+)
 create mode 100644 watchman-support.c
 create mode 100644 watchman-support.h

diff --git a/Makefile b/Makefile
index c8be0e7..65ab0f4 100644
--- a/Makefile
+++ b/Makefile

@@ -451,6 +451,7 @@ MSGFMT = msgfmt
 CURL_CONFIG = curl-config
 PTHREAD_LIBS = -lpthread
 PTHREAD_CFLAGS =
+WATCHMAN_LIBS =
 GCOV = gcov

 export TCL_PATH TCLTK_PATH

@@ -1416,6 +1417,13 @@ else
        LIB_OBJS += thread-utils.o
 endif

+ifdef USE_WATCHMAN
+       LIB_H += watchman-support.h
+       LIB_OBJS += watchman-support.o
+       WATCHMAN_LIBS = -lwatchman
+       BASIC_CFLAGS += -DUSE_WATCHMAN
+endif
+
 ifdef HAVE_PATHS_H
        BASIC_CFLAGS += -DHAVE_PATHS_H
 endif

@@ -2025,6 +2033,9 @@ git-remote-testsvn$X: remote-testsvn.o GIT-LDFLAGS $(GITLIBS) $(VCSSVN_LIB)
        $(QUIET_LINK)$(CC) $(ALL_CFLAGS) -o $@ $(ALL_LDFLAGS) $(filter %.o,$^) $(LIBS) \
        $(VCSSVN_LIB)

+git-index-helper$X: index-helper.o GIT-LDFLAGS $(GITLIBS)
+       $(QUIET_LINK)$(CC) $(ALL_CFLAGS) -o $@ $(ALL_LDFLAGS) $(filter %.o,$^) $(LIBS) $(WATCHMAN_LIBS)
+
 $(REMOTE_CURL_ALIASES): $(REMOTE_CURL_PRIMARY)
        $(QUIET_LNCP)$(RM) $@ && \
        ln $< $@ 2>/dev/null || \

@@ -2164,6 +2175,7 @@ GIT-BUILD-OPTIONS: FORCE
        @echo NO_PYTHON=\''$(subst ','\'',$(subst ','\'',$(NO_PYTHON)))'\' >>$@+
        @echo NO_UNIX_SOCKETS=\''$(subst ','\'',$(subst ','\'',$(NO_UNIX_SOCKETS)))'\' >>$@+
        @echo NO_MMAP=\''$(subst ','\'',$(subst ','\'',$(NO_MMAP)))'\' >>$@+
+       @echo USE_WATCHMAN=\''$(subst ','\'',$(subst ','\'',$(USE_WATCHMAN)))'\' >>$@+
 ifdef TEST_OUTPUT_DIRECTORY
        @echo TEST_OUTPUT_DIRECTORY=\''$(subst ','\'',$(subst ','\'',$(TEST_OUTPUT_DIRECTORY)))'\' >>$@+
 endif

diff --git a/cache.h b/cache.h
index f10992d..452aea2 100644
--- a/cache.h
+++ b/cache.h

@@ -696,6 +696,7 @@ extern char *git_replace_ref_base;

 extern int fsync_object_files;
 extern int core_preload_index;
+extern int core_watchman_sync_timeout;
 extern int core_apply_sparse_checkout;
 extern int precomposed_unicode;
 extern int protect_hfs;

diff --git a/config.c b/config.c
index 9ba40bc..e6dc141 100644
--- a/config.c
+++ b/config.c

@@ -882,6 +882,11 @@ static int git_default_core_config(const char *var, const char *value)
                return 0;
        }

+       if (!strcmp(var, "core.watchmansynctimeout")) {
+               core_watchman_sync_timeout = git_config_int(var, value);
+               return 0;
+       }
+
        if (!strcmp(var, "core.createobject")) {
                if (!strcmp(value, "rename"))
                        object_creation_mode = OBJECT_CREATION_USES_RENAMES;

diff --git a/configure.ac b/configure.ac
index 0cd9f46..334d63b 100644
--- a/configure.ac
+++ b/configure.ac

@@ -1099,6 +1099,14 @@ AC_COMPILE_IFELSE([BSD_SYSCTL_SRC],
        HAVE_BSD_SYSCTL=])
 GIT_CONF_SUBST([HAVE_BSD_SYSCTL])

+#
+# Check for watchman client library
+
+AC_CHECK_LIB([watchman], [watchman_connect],
+       [USE_WATCHMAN=YesPlease],
+       [USE_WATCHMAN=])
+GIT_CONF_SUBST([USE_WATCHMAN])
+
 ## Other checks.
 # Define USE_PIC if you need the main git objects to be built with -fPIC
 # in order to build and link perl/Git.so.  x86-64 seems to need this.

diff --git a/environment.c b/environment.c
index 6dec9d0..35e03c7 100644
--- a/environment.c
+++ b/environment.c

@@ -94,6 +94,9 @@ int core_preload_index = 1;
  */
 int ignore_untracked_cache_config;

+int core_watchman_sync_timeout = 300;
+
+