Windows supports shared memory, but the semantics is a bit different
than POSIX shm. The most noticeable thing is there's no way to get the
shared memory's size by the reader, and wrapping fstat to do that
would be hell. So the shm size is added near the end, hidden away from
shm users (storing it in headers would cause more problems with munmap,
storing it as a separate shm is even worse).
PostMessage is used instead of UNIX signals for notification.
Lightweight (at least code-wise) on the client side.
Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@xxxxxxxxx>
---
config.mak.uname | 2 ++
index-helper.c | 48 ++++++++++++++++++++++++++++
read-cache.c | 6 ++++
shm.c | 96 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++
4 files changed, 152 insertions(+)
diff --git a/config.mak.uname b/config.mak.uname
index 7e66d80..74e764f 100644
--- a/config.mak.uname
+++ b/config.mak.uname
@@ -377,6 +377,7 @@ ifndef DEBUG
else
BASIC_CFLAGS += -Zi -MDd
endif
+ PROGRAM_OBJS += index-helper.o
X = .exe
endif
ifeq ($(uname_S),Interix)
@@ -532,6 +533,7 @@ ifneq (,$(wildcard ../THIS_IS_MSYSGIT))
else
NO_CURL = YesPlease
endif
+ PROGRAM_OBJS += index-helper.o
endif
ifeq ($(uname_S),QNX)
COMPAT_CFLAGS += -DSA_RESTART=0
diff --git a/index-helper.c b/index-helper.c
index 4262678..7c2a0e7 100644
--- a/index-helper.c
+++ b/index-helper.c
@@ -147,6 +147,51 @@ static void loop(const char *pid_file, int idle_in_seconds)
; /* do nothing, all is handled by signal handlers already */
}
+#elif defined(GIT_WINDOWS_NATIVE)
+
+static void loop(const char *pid_file, int idle_in_seconds)
+{
+ HWND hwnd;
+ UINT_PTR timer = 0;
+ MSG msg;
+ HINSTANCE hinst = GetModuleHandle(NULL);
+ WNDCLASS wc;
+
+ /*
+ * Emulate UNIX signals by sending WM_USER+x to a
+ * window. Register window class and create a new window to
+ * catch these messages.
+ */
+ memset(&wc, 0, sizeof(wc));
+ wc.lpfnWndProc = DefWindowProc;
+ wc.hInstance = hinst;
+ wc.lpszClassName = "git-index-helper";
+ if (!RegisterClass(&wc))
+ die_errno(_("could not register new window class"));
+
+ hwnd = CreateWindow("git-index-helper", pid_file,
+ 0, 0, 0, 1, 1, NULL, NULL, hinst, NULL);
+ if (!hwnd)
+ die_errno(_("could not register new window"));
+
+ refresh(0);
+ while (1) {
+ timer = SetTimer(hwnd, timer, idle_in_seconds * 1000, NULL);
+ if (!timer)
+ die(_("no timer!"));
+ if (!GetMessage(&msg, hwnd, 0, 0) || msg.message == WM_TIMER)
+ break;
+ switch (msg.message) {
+ case WM_USER:
+ refresh(0);
+ break;
+ default:
+ /* just reset the timer */
+ break;
+ }
+ }
+}
+
#else
static void loop(const char *pid_file, int idle_in_seconds)
@@ -192,6 +237,9 @@ int main(int argc, char **argv)
git_path("index-helper.pid"),
LOCK_DIE_ON_ERROR);
strbuf_addf(&sb,
+#ifdef GIT_WINDOWS_NATIVE
+ "HWND"
+#endif
"%" PRIuMAX, (uintmax_t) getpid());
write_in_full(fd, sb.buf, sb.len);
commit_lock_file(&lock);
diff --git a/read-cache.c b/read-cache.c
index d6eb17f..0ca3345 100644
--- a/read-cache.c
+++ b/read-cache.c
@@ -1489,6 +1489,12 @@ static void poke_daemon(const struct stat *st, int refresh_cache)
pid_t pid = strtoul(sb.buf, &end, 10);
if (end && sb.buf + st->st_size == end)
kill(pid, refresh_cache ? SIGHUP : SIGUSR1);
+#elif defined(GIT_WINDOWS_NATIVE)
+ if (starts_with(sb.buf, "HWND")) {
+ HWND hwnd = FindWindow("git-index-helper", sb.buf);
+ PostMessage(hwnd, refresh_cache ? WM_USER : WM_USER + 1,
+ 0, 0);
+ }
#endif
}
close(fd);
diff --git a/shm.c b/shm.c
index 4ec1a00..04d8a35 100644
--- a/shm.c
+++ b/shm.c
@@ -52,6 +52,102 @@ void git_shm_unlink(const char *fmt, ...)
shm_unlink(path);
}
+#elif defined(GIT_WINDOWS_NATIVE)
+
+#define SHM_PATH_LEN 82 /* a little bit longer than POSIX because of "Local\\" */
+
+static ssize_t create_shm_map(int oflag, int perm, ssize_t length,
+ void **mmap, int prot, int flags,
+ const char *path, unsigned long page_size)
+{
+ size_t real_length;
+ void *last_page;
+ HANDLE h;
+
+ assert(perm == 0700);
+ assert(oflag == (O_CREAT | O_EXCL | O_RDWR));
+ assert(prot == (PROT_READ | PROT_WRITE));
+ assert(flags == MAP_SHARED);
+ assert(length >= 0);
+
+ real_length = length;
+ if (real_length % page_size)
+ real_length += page_size - (real_length % page_size);
+ real_length += page_size;
+ h = CreateFileMapping(INVALID_HANDLE_VALUE, NULL, PAGE_READWRITE, 0,
+ real_length, path);
+ if (!h)
+ return -1;
+ *mmap = MapViewOfFile(h, FILE_MAP_ALL_ACCESS, 0, 0, real_length);
+ CloseHandle(h);
+ if (!*mmap)
+ return -1;
+ last_page = (unsigned char *)*mmap + real_length - page_size;
+ *(unsigned long *)last_page = length;
+ return length;
+}
+
+static ssize_t open_shm_map(int oflag, int perm, ssize_t length, void **mmap,
+ int prot, int flags, const char *path,
+ unsigned long page_size)
+{
+ void *last_page;
+ HANDLE h;
+
+ assert(perm == 0700);
+ assert(oflag == O_RDONLY);
+ assert(prot == PROT_READ);
+ assert(flags == MAP_SHARED);
+ assert(length <= 0);
+
+ h = OpenFileMapping(FILE_MAP_READ, FALSE, path);
+ if (!h)
+ return -1;
+ *mmap = MapViewOfFile(h, FILE_MAP_READ, 0, 0, 0);
+ CloseHandle(h);
+ if (!*mmap)
+ return -1;
+ if (length < 0) {
+ MEMORY_BASIC_INFORMATION mbi;
+ if (!VirtualQuery(*mmap, &mbi, sizeof(mbi))) {
+ UnmapViewOfFile(*mmap);
+ return -1;
+ }
+ if (mbi.RegionSize % page_size)
+ die("expected size %lu to be %lu aligned",
+ mbi.RegionSize, page_size);
+ last_page = (unsigned char *)*mmap + mbi.RegionSize - page_size;
+ length = *(unsigned long *)last_page;
+ }
+ return length;
+}
+
+ssize_t git_shm_map(int oflag, int perm, ssize_t length, void **mmap,
+ int prot, int flags, const char *fmt, ...)
+{
+ SYSTEM_INFO si;
+ va_list ap;
+ char path[SHM_PATH_LEN];
+
+ GetSystemInfo(&si);
+
+ strcpy(path, "Local\\");
+ va_start(ap, fmt);
+ vsprintf(path + strlen(path), fmt, ap);
+ va_end(ap);
+
+ if (oflag & O_CREAT)
+ return create_shm_map(oflag, perm, length, mmap, prot,
+ flags, path, si.dwPageSize);
+ else
+ return open_shm_map(oflag, perm, length, mmap, prot,
+ flags, path, si.dwPageSize);
+}
+
+void git_shm_unlink(const char *fmt, ...)
+{
+}
+
#else
ssize_t git_shm_map(int oflag, int perm, ssize_t length, void **mmap,
--
2.1.0.rc0.66.gb9187ad
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