os: add os.stat() and helpers

vlib/os/os.v

@@ -977,3 +977,18 @@ pub fn config_dir() !string {
 	}
 	return error('Cannot find config directory')
 }
+
+pub struct Stat {
+pub:
+	dev   u64
+	inode u64
+	mode  u32
+	nlink u64
+	uid   u32
+	gid   u32
+	rdev  u64
+	size  u64
+	atime i64
+	mtime i64
+	ctime i64
+}

vlib/os/os_stat_default.c.v

@@ -0,0 +1,81 @@
+module os
+
+// stat returns a platform-agnostic Stat struct comparable to what is
+// available in other programming languages and fails with the POSIX
+// error if the stat call fails. If a link is stat'd, the stat info
+// for the link is provided.
+pub fn stat(path string) !Stat {
+	mut s := C.stat{}
+	unsafe {
+		res := C.lstat(&char(path.str), &s)
+		if res != 0 {
+			return error_posix()
+		}
+		return Stat{
+			dev: s.st_dev
+			inode: s.st_ino
+			nlink: s.st_nlink
+			mode: s.st_mode
+			uid: s.st_uid
+			gid: s.st_gid
+			rdev: s.st_rdev
+			size: s.st_size
+			atime: s.st_atime
+			mtime: s.st_mtime
+			ctime: s.st_ctime
+		}
+	}
+}
+
+// get_filetype returns the FileType from the Stat struct
+pub fn (st Stat) get_filetype() FileType {
+	match st.mode & u32(C.S_IFMT) {
+		u32(C.S_IFREG) {
+			return .regular
+		}
+		u32(C.S_IFDIR) {
+			return .directory
+		}
+		u32(C.S_IFCHR) {
+			return .character_device
+		}
+		u32(C.S_IFBLK) {
+			return .block_device
+		}
+		u32(C.S_IFIFO) {
+			return .fifo
+		}
+		u32(C.S_IFLNK) {
+			return .symbolic_link
+		}
+		u32(C.S_IFSOCK) {
+			return .socket
+		}
+		else {
+			return .unknown
+		}
+	}
+}
+
+// get_mode returns the file type and permissions (readable, writable, executable)
+// in owner/group/others format
+pub fn (st Stat) get_mode() FileMode {
+	return FileMode{
+		typ: st.get_filetype()
+		owner: FilePermission{
+			read: (st.mode & u32(C.S_IRUSR)) != 0
+			write: (st.mode & u32(C.S_IWUSR)) != 0
+			execute: (st.mode & u32(C.S_IXUSR)) != 0
+		}
+		group: FilePermission{
+			read: (st.mode & u32(C.S_IRGRP)) != 0
+			write: (st.mode & u32(C.S_IWGRP)) != 0
+			execute: (st.mode & u32(C.S_IXGRP)) != 0
+		}
+		others: FilePermission{
+			read: (st.mode & u32(C.S_IROTH)) != 0
+			write: (st.mode & u32(C.S_IWOTH)) != 0
+			execute: (st.mode & u32(C.S_IXOTH)) != 0
+		}
+	}
+}

vlib/os/os_stat_test.v

@@ -0,0 +1,57 @@
+import os
+import rand
+import time
+
+fn test_stat() {
+	start_time := time.utc()
+
+	temp_dir := os.join_path(os.temp_dir(), rand.ulid())
+	os.mkdir(temp_dir)!
+	defer {
+		os.rmdir(temp_dir) or {}
+	}
+
+	test_file := os.join_path(temp_dir, rand.ulid())
+	test_content := rand.ulid()
+	os.write_file(test_file, test_content)!
+	defer {
+		os.rm(test_file) or {}
+	}
+
+	end_time := time.utc()
+
+	mut fstat := os.stat(test_file)!
+	assert fstat.get_filetype() == .regular
+	assert fstat.size == u64(test_content.len)
+	assert fstat.ctime >= start_time.unix
+	assert fstat.ctime <= end_time.unix
+	assert fstat.mtime >= start_time.unix
+	assert fstat.mtime <= end_time.unix
+
+	$if !windows {
+		os.chmod(test_file, 0o600)!
+		fstat = os.stat(test_file)!
+
+		mut fmode := fstat.get_mode()
+		assert fmode.typ == .regular
+		assert fmode.owner.read && fmode.owner.write && !fmode.owner.execute
+		assert !fmode.group.read && !fmode.group.write && !fmode.group.execute
+		assert !fmode.others.read && !fmode.others.write && !fmode.others.execute
+
+		os.chmod(test_file, 0o421)!
+		fstat = os.stat(test_file)!
+		fmode = fstat.get_mode()
+		assert fmode.owner.read && !fmode.owner.write && !fmode.owner.execute
+		assert !fmode.group.read && fmode.group.write && !fmode.group.execute
+		assert !fmode.others.read && !fmode.others.write && fmode.others.execute
+
+		os.chmod(test_file, 0o600)!
+	}
+
+	// When using the Time struct, allow for up to 1 second difference due to nanoseconds
+	// which are not captured in the timestamp
+	dstat := os.stat(temp_dir)!
+	assert dstat.get_filetype() == .directory
+	assert fstat.dev == dstat.dev, 'File and directory should be created on same device'
+	assert fstat.rdev == dstat.rdev, 'File and directory should have same device ID'
+}

vlib/os/os_stat_windows.c.v

@@ -0,0 +1,63 @@
+module os
+
+// stat returns a platform-agnostic Stat struct comparable to what is
+// available in other programming languages and fails with the POSIX
+// error if the stat call fails. If a link is stat'd, the stat info
+// for the link is provided.
+pub fn stat(path string) !Stat {
+	mut s := C.__stat64{}
+	unsafe {
+		res := C._wstat64(path.to_wide(), &s)
+		if res != 0 {
+			return error_posix()
+		}
+		return Stat{
+			dev: s.st_dev
+			inode: s.st_ino
+			nlink: s.st_nlink
+			mode: s.st_mode
+			uid: s.st_uid
+			gid: s.st_gid
+			rdev: s.st_rdev
+			size: s.st_size
+			atime: s.st_atime
+			mtime: s.st_mtime
+			ctime: s.st_ctime
+		}
+	}
+}
+
+// get_filetype returns the FileType from the Stat struct
+pub fn (st Stat) get_filetype() FileType {
+	match st.mode & u32(C.S_IFMT) {
+		u32(C.S_IFDIR) {
+			return .directory
+		}
+		else {
+			return .regular
+		}
+	}
+}
+
+// get_mode returns the file type and permissions (readable, writable, executable)
+// in owner/group/others format, however, they will all be the same for Windows
+pub fn (st Stat) get_mode() FileMode {
+	return FileMode{
+		typ: st.get_filetype()
+		owner: FilePermission{
+			read: (st.mode & u32(C.S_IREAD)) != 0
+			write: (st.mode & u32(C.S_IWRITE)) != 0
+			execute: (st.mode & u32(C.S_IEXEC)) != 0
+		}
+		group: FilePermission{
+			read: (st.mode & u32(C.S_IREAD)) != 0
+			write: (st.mode & u32(C.S_IWRITE)) != 0
+			execute: (st.mode & u32(C.S_IEXEC)) != 0
+		}
+		others: FilePermission{
+			read: (st.mode & u32(C.S_IREAD)) != 0
+			write: (st.mode & u32(C.S_IWRITE)) != 0
+			execute: (st.mode & u32(C.S_IEXEC)) != 0
+		}
+	}
+}

vlib/os/os_structs_stat_default.c.v

@@ -1,9 +1,19 @@
 module os
 
+// Minimal stat struct as specified in
+// https://pubs.opengroup.org/onlinepubs/9699919799/basedefs/sys_stat.h.html
 pub struct C.stat {
-	st_size  u64
+	st_dev   u64
+	st_ino   u64
 	st_mode  u32
+	st_nlink u64
+	st_uid   u32
+	st_gid   u32
+	st_rdev  u64
+	st_size  u64
+	st_atime int
 	st_mtime int
+	st_ctime int
 }
 
 pub struct C.__stat64 {

vlib/os/os_structs_stat_windows.v

@@ -0,0 +1,15 @@
+module os
+
+pub struct C.__stat64 {
+	st_dev   u32 // 4
+	st_ino   u16 // 2
+	st_mode  u16 // 2
+	st_nlink u16 // 2	
+	st_uid   u16 // 2
+	st_gid   u16 // 2
+	st_rdev  u32 // 4
+	st_size  u64 // 8
+	st_atime i64 // 8
+	st_mtime i64 // 8
+	st_ctime i64 // 8
+}