From 54d1a29267425194ea80c376f109c29912702abf Mon Sep 17 00:00:00 2001
From: Alexey <alex.esprit@gmail.com>
Date: Wed, 29 Apr 2020 22:01:19 +0300
Subject: [PATCH] dl: improve module

---
 vlib/dl/dl_nix.c.v     | 18 ++++++++++++++----
 vlib/dl/dl_test.v      | 30 ++++++++++++++++++++++++------
 vlib/dl/dl_windows.c.v | 18 ++++++++++++++----
 3 files changed, 52 insertions(+), 14 deletions(-)

diff --git a/vlib/dl/dl_nix.c.v b/vlib/dl/dl_nix.c.v
index 080fcdd436..6b910005ab 100644
--- a/vlib/dl/dl_nix.c.v
+++ b/vlib/dl/dl_nix.c.v
@@ -2,18 +2,28 @@ module dl
 
 #include <dlfcn.h>
 
-fn C.dlopen(filename charptr, flags int) voidptr
-fn C.dlsym(handle voidptr, symbol charptr) voidptr
-
 pub const (
 	RTLD_NOW = C.RTLD_NOW
-	DL_EXT = '.so'
+	DL_EXT   = '.so'
 )
 
+fn C.dlopen(filename charptr, flags int) voidptr
+
+fn C.dlsym(handle voidptr, symbol charptr) voidptr
+
+fn C.dlclose(handle voidptr) int
+
+// open loads the dynamic shared object.
 pub fn open(filename string, flags int) voidptr {
 	return C.dlopen(filename.str, flags)
 }
 
+// close frees a given shared object.
+pub fn close(handle voidptr) bool {
+	return C.dlclose(handle) == 0
+}
+
+// sym returns an address of a symbol in a given shared object.
 pub fn sym(handle voidptr, symbol string) voidptr {
 	return C.dlsym(handle, symbol.str)
 }
diff --git a/vlib/dl/dl_test.v b/vlib/dl/dl_test.v
index 7451ed81f2..ea292cc4d8 100644
--- a/vlib/dl/dl_test.v
+++ b/vlib/dl/dl_test.v
@@ -2,27 +2,45 @@ import dl
 
 fn test_dl() {
 	$if linux {
-		run_test_linux()
+		run_test_invalid_lib_linux()
 		return
 	}
 	$if windows {
-		run_test_windows()
+		run_test_invalid_lib_windows()
+		run_test_valid_lib_windows()
+		run_test_invalid_sym_windows()
+		run_test_valid_sym_windows()
 		return
 	} $else {
 		eprint('currently not implemented on this platform')
 	}
 }
 
-fn run_test_linux() {
+fn run_test_invalid_lib_linux() {
 	// ensure a not-existing dl won't be loaded
 	h := dl.open('not-existing-dynamic-link-library', dl.RTLD_NOW)
-	// println('handle = $h')
 	assert h == 0
 }
 
-fn run_test_windows() {
+fn run_test_invalid_lib_windows() {
 	// ensure a not-existing dl won't be loaded
 	h := dl.open('not-existing-dynamic-link-library', dl.RTLD_NOW)
-	// println('handle = $h')
 	assert h == 0
 }
+
+fn run_test_valid_lib_windows() {
+	h := dl.open('shell32', dl.RTLD_NOW)
+	assert h != 0
+}
+
+fn run_test_invalid_sym_windows() {
+	h := dl.open('shell32', dl.RTLD_NOW)
+	proc := dl.sym(h, 'CommandLineToArgvW2')
+	assert proc == 0
+}
+
+fn run_test_valid_sym_windows() {
+	h := dl.open('shell32', dl.RTLD_NOW)
+	proc := dl.sym(h, 'CommandLineToArgvW')
+	assert proc != 0
+}
diff --git a/vlib/dl/dl_windows.c.v b/vlib/dl/dl_windows.c.v
index d602bd1257..ec971447c2 100644
--- a/vlib/dl/dl_windows.c.v
+++ b/vlib/dl/dl_windows.c.v
@@ -2,17 +2,27 @@ module dl
 
 pub const (
 	RTLD_NOW = 0
-	DL_EXT = '.dll'
+	DL_EXT   = '.dll'
 )
 
-fn C.LoadLibraryA(libfilename byteptr) voidptr
-fn C.GetProcAddress(handle voidptr, procname byteptr) voidptr
+fn C.LoadLibrary(libfilename C.LPCWSTR) voidptr
 
+fn C.GetProcAddress(handle voidptr, procname C.LPCSTR) voidptr
+
+fn C.FreeLibrary(handle voidptr) bool
+
+// open loads a given module into the address space of the calling process.
 pub fn open(filename string, flags int) voidptr {
-	res := C.LoadLibraryA(filename.str)
+	res := C.LoadLibrary(filename.to_wide())
 	return res
 }
 
+// close frees the loaded a given module.
+pub fn close(handle voidptr) bool {
+	return C.FreeLibrary(handle)
+}
+
+// sym returns an address of an exported function or variable from a given module.
 pub fn sym(handle voidptr, symbol string) voidptr {
 	return C.GetProcAddress(handle, symbol.str)
 }