fuse: add FileSystemOpenEx interface

fuse/fsop.go

@@ -146,6 +146,25 @@ type Stat_t struct {
 	Flags uint32
 }
 
+// FileInfo_t contains open file information.
+// This structure is analogous to the FUSE struct fuse_file_info.
+type FileInfo_t struct {
+	// Open flags: a combination of the fuse.O_* constants.
+	Flags int
+
+	// Use direct I/O on this file. [IGNORED on Windows]
+	DirectIo bool
+
+	// Do not invalidate file cache. [IGNORED on Windows]
+	KeepCache bool
+
+	// File is not seekable. [IGNORED on Windows]
+	NonSeekable bool
+
+	// File handle.
+	Fh uint64
+}
+
 /*
 // Lock_t contains file locking information.
 // This structure is analogous to the POSIX struct flock.
@@ -290,6 +309,16 @@ type FileSystemInterface interface {
 	Listxattr(path string, fill func(name string) bool) int
 }
 
+// FileSystemOpenEx is the interface that wraps the OpenEx and CreateEx methods.
+//
+// OpenEx and CreateEx are similar to Open and Create except that they allow
+// direct manipulation of the FileInfo_t struct (which is analogous to the
+// FUSE struct fuse_file_info).
+type FileSystemOpenEx interface {
+	CreateEx(path string, mode uint32, fi *FileInfo_t) int
+	OpenEx(path string, fi *FileInfo_t) int
+}
+
 // FileSystemChflags is the interface that wraps the Chflags method.
 //
 // Chflags changes the BSD file flags (Windows file attributes). [OSX and Windows only]

fuse/host.go

@@ -219,9 +219,21 @@ func hostOpen(path0 *c_char, fi0 *c_struct_fuse_file_info) (errc0 c_int) {
 	defer recoverAsErrno(&errc0)
 	fsop := hostHandleGet(c_fuse_get_context().private_data).fsop
 	path := c_GoString(path0)
-	errc, rslt := fsop.Open(path, int(fi0.flags))
-	fi0.fh = c_uint64_t(rslt)
-	return c_int(errc)
+	intf, ok := fsop.(FileSystemOpenEx)
+	if ok {
+		fi := FileInfo_t{Flags: int(fi0.flags)}
+		errc := intf.OpenEx(path, &fi)
+		c_hostAsgnCfileinfo(fi0,
+			c_bool(fi.DirectIo),
+			c_bool(fi.KeepCache),
+			c_bool(fi.NonSeekable),
+			c_uint64_t(fi.Fh))
+		return c_int(errc)
+	} else {
+		errc, rslt := fsop.Open(path, int(fi0.flags))
+		fi0.fh = c_uint64_t(rslt)
+		return c_int(errc)
+	}
 }
 
 func hostRead(path0 *c_char, buff0 *c_char, size0 c_size_t, ofst0 c_fuse_off_t,
@@ -447,15 +459,33 @@ func hostCreate(path0 *c_char, mode0 c_fuse_mode_t, fi0 *c_struct_fuse_file_info
 	defer recoverAsErrno(&errc0)
 	fsop := hostHandleGet(c_fuse_get_context().private_data).fsop
 	path := c_GoString(path0)
-	errc, rslt := fsop.Create(path, int(fi0.flags), uint32(mode0))
-	if -ENOSYS == errc {
-		errc = fsop.Mknod(path, S_IFREG|uint32(mode0), 0)
-		if 0 == errc {
-			errc, rslt = fsop.Open(path, int(fi0.flags))
+	intf, ok := fsop.(FileSystemOpenEx)
+	if ok {
+		fi := FileInfo_t{Flags: int(fi0.flags)}
+		errc := intf.CreateEx(path, uint32(mode0), &fi)
+		if -ENOSYS == errc {
+			errc = fsop.Mknod(path, S_IFREG|uint32(mode0), 0)
+			if 0 == errc {
+				errc = intf.OpenEx(path, &fi)
+			}
 		}
+		c_hostAsgnCfileinfo(fi0,
+			c_bool(fi.DirectIo),
+			c_bool(fi.KeepCache),
+			c_bool(fi.NonSeekable),
+			c_uint64_t(fi.Fh))
+		return c_int(errc)
+	} else {
+		errc, rslt := fsop.Create(path, int(fi0.flags), uint32(mode0))
+		if -ENOSYS == errc {
+			errc = fsop.Mknod(path, S_IFREG|uint32(mode0), 0)
+			if 0 == errc {
+				errc, rslt = fsop.Open(path, int(fi0.flags))
+			}
+		}
+		fi0.fh = c_uint64_t(rslt)
+		return c_int(errc)
 	}
-	fi0.fh = c_uint64_t(rslt)
-	return c_int(errc)
 }
 
 func hostFtruncate(path0 *c_char, size0 c_fuse_off_t, fi0 *c_struct_fuse_file_info) (errc0 c_int) {

fuse/host_cgo.go

@@ -379,6 +379,18 @@ static inline void hostCstatFromFusestat(fuse_stat_t *stbuf,
 #endif
 }
 
+static inline void hostAsgnCfileinfo(struct fuse_file_info *fi,
+	bool direct_io,
+	bool keep_cache,
+	bool nonseekable,
+	uint64_t fh)
+{
+	fi->direct_io = direct_io;
+	fi->keep_cache = keep_cache;
+	fi->nonseekable = nonseekable;
+	fi->fh = fh;
+}
+
 static inline int hostFilldir(fuse_fill_dir_t filler, void *buf,
 	char *name, fuse_stat_t *stbuf, fuse_off_t off)
 {
@@ -687,6 +699,17 @@ func c_hostCstatFromFusestat(stbuf *c_fuse_stat_t,
 		birthtimNsec,
 		flags)
 }
+func c_hostAsgnCfileinfo(fi *c_struct_fuse_file_info,
+	direct_io c_bool,
+	keep_cache c_bool,
+	nonseekable c_bool,
+	fh c_uint64_t) {
+	C.hostAsgnCfileinfo(fi,
+		direct_io,
+		keep_cache,
+		nonseekable,
+		fh)
+}
 func c_hostFilldir(filler c_fuse_fill_dir_t,
 	buf unsafe.Pointer, name *c_char, stbuf *c_fuse_stat_t, off c_fuse_off_t) c_int {
 	return C.hostFilldir(filler, buf, name, stbuf, off)

fuse/host_nocgo_windows.go

@@ -426,6 +426,22 @@ func c_hostCstatFromFusestat(stbuf *c_fuse_stat_t,
 		stbuf.st_birthtim.tv_nsec = uintptr(ctimNsec)
 	}
 }
+func c_hostAsgnCfileinfo(fi *c_struct_fuse_file_info,
+	direct_io c_bool,
+	keep_cache c_bool,
+	nonseekable c_bool,
+	fh c_uint64_t) {
+	if direct_io {
+		fi.bits |= 1
+	}
+	if keep_cache {
+		fi.bits |= 2
+	}
+	if nonseekable {
+		fi.bits |= 8
+	}
+	fi.fh = fh
+}
 func c_hostFilldir(filler c_fuse_fill_dir_t,
 	buf unsafe.Pointer, name *c_char, stbuf *c_fuse_stat_t, off c_fuse_off_t) c_int {
 	var r uintptr