From 03525843a062414a9099a5f392773f2083bceb93 Mon Sep 17 00:00:00 2001
From: Alexander Medvednikov <alexander@medvednikov.com>
Date: Mon, 18 May 2020 22:54:08 +0200
Subject: [PATCH] parser: do not allow calling private functions

---
 vlib/builtin/cfns.c.v      |  2 +-
 vlib/os/os.v               |  2 +-
 vlib/strconv/atoi.v        |  2 +-
 vlib/time/time_nix.c.v     |  2 +-
 vlib/time/time_windows.c.v |  2 +-
 vlib/v/checker/checker.v   | 66 +++++++++++++++++++++-----------------
 vlib/v/parser/fn.v         |  1 +
 vlib/v/util/scanning.v     | 10 +++---
 vlib/v/util/util.v         |  2 +-
 9 files changed, 49 insertions(+), 40 deletions(-)

diff --git a/vlib/builtin/cfns.c.v b/vlib/builtin/cfns.c.v
index ba46743ec0..a3e1c66d0e 100644
--- a/vlib/builtin/cfns.c.v
+++ b/vlib/builtin/cfns.c.v
@@ -31,7 +31,7 @@ fn C.backtrace_symbols(a &voidptr, size int)  &charptr
 fn C.backtrace_symbols_fd(a &voidptr, size int, fd int)
 
 // <libproc.h>
-fn proc_pidpath(int, voidptr, int) int
+pub fn proc_pidpath(int, voidptr, int) int
 
 
 fn C.realpath(byteptr, byteptr) &char
diff --git a/vlib/os/os.v b/vlib/os/os.v
index 807514e28e..ab86dbf195 100644
--- a/vlib/os/os.v
+++ b/vlib/os/os.v
@@ -836,7 +836,7 @@ pub fn on_segfault(f voidptr) {
 fn C.getpid() int
 
 
-fn C.proc_pidpath(int, byteptr, int) int
+//fn C.proc_pidpath(int, byteptr, int) int
 
 
 fn C.readlink() int
diff --git a/vlib/strconv/atoi.v b/vlib/strconv/atoi.v
index 198427cab8..97ba9e5eda 100644
--- a/vlib/strconv/atoi.v
+++ b/vlib/strconv/atoi.v
@@ -12,7 +12,7 @@ const (
 	max_u64 = u64(C.UINT64_MAX)// as u64 // use this until we add support
 )
 
-fn byte_to_lower(c byte) byte {
+pub fn byte_to_lower(c byte) byte {
 	return c | (`x` - `X`)
 }
 
diff --git a/vlib/time/time_nix.c.v b/vlib/time/time_nix.c.v
index da210c5c47..c1f366a6f9 100644
--- a/vlib/time/time_nix.c.v
+++ b/vlib/time/time_nix.c.v
@@ -29,7 +29,7 @@ struct C.timespec {
 // the first arg is defined in include/bits/types.h as `__S32_TYPE`, which is `int`
 fn C.clock_gettime(int, &C.timespec)
 
-fn sys_mono_now() u64 {
+pub fn sys_mono_now() u64 {
 	$if macos {
 		return sys_mono_now_darwin()
 	} $else {
diff --git a/vlib/time/time_windows.c.v b/vlib/time/time_windows.c.v
index 66b7324e66..47f8298290 100644
--- a/vlib/time/time_windows.c.v
+++ b/vlib/time/time_windows.c.v
@@ -41,7 +41,7 @@ fn init_win_time_start() u64 {
 	return s
 }
 
-fn sys_mono_now() u64 {
+pub fn sys_mono_now() u64 {
 	tm := u64(0)
 	C.QueryPerformanceCounter(&tm) // XP or later never fail
 	return (tm - start_time) * 1_000_000_000 / freq_time
diff --git a/vlib/v/checker/checker.v b/vlib/v/checker/checker.v
index 06dba3e4db..2772414cd9 100644
--- a/vlib/v/checker/checker.v
+++ b/vlib/v/checker/checker.v
@@ -878,6 +878,10 @@ pub fn (mut c Checker) call_fn(mut call_expr ast.CallExpr) table.Type {
 				call_expr.pos)
 		}
 	}
+	if !f.is_pub && !f.is_c && !c.is_builtin_mod && !c.pref.is_test && f.mod != c.mod && f.name !=
+		'' && f.mod != '' {
+		c.warn('function `$f.name` is private. curmod=$c.mod fmod=$f.mod', call_expr.pos)
+	}
 	call_expr.return_type = f.return_type
 	if f.return_type == table.void_type && f.ctdefine.len > 0 && f.ctdefine !in c.pref.compile_defines {
 		call_expr.should_be_skipped = true
@@ -1483,35 +1487,7 @@ fn (mut c Checker) stmt(node ast.Stmt) {
 			c.check_expr_opt_call(it.expr, etype, false)
 		}
 		ast.FnDecl {
-			if !it.is_c && !it.is_js && !c.is_builtin_mod {
-				c.check_valid_snake_case(it.name, 'function name', it.pos)
-			}
-			if it.is_method {
-				sym := c.table.get_type_symbol(it.receiver.typ)
-				if sym.kind == .interface_ {
-					c.error('interfaces cannot be used as method receiver', it.receiver_pos)
-				}
-				// if sym.has_method(it.name) {
-				// c.warn('duplicate method `$it.name`', it.pos)
-				// }
-			}
-			if !it.is_c {
-				// Make sure all types are valid
-				for arg in it.args {
-					sym := c.table.get_type_symbol(arg.typ)
-					if sym.kind == .placeholder {
-						c.error('unknown type `$sym.name`', it.pos)
-					}
-				}
-			}
-			c.expected_type = table.void_type
-			c.fn_return_type = it.return_type
-			c.stmts(it.stmts)
-			if !it.is_c && !it.is_js && !it.no_body && it.return_type != table.void_type &&
-				!c.returns && it.name !in ['panic', 'exit'] {
-				c.error('missing return at end of function `$it.name`', it.pos)
-			}
-			c.returns = false
+			c.fn_decl(it)
 		}
 		ast.ForCStmt {
 			c.in_for_count++
@@ -2312,3 +2288,35 @@ fn (mut c Checker) warn_or_error(message string, pos token.Position, warn bool)
 fn (c &Checker) fileis(s string) bool {
 	return c.file.path.contains(s)
 }
+
+fn (mut c Checker) fn_decl(it ast.FnDecl) {
+	if !it.is_c && !it.is_js && !c.is_builtin_mod {
+		c.check_valid_snake_case(it.name, 'function name', it.pos)
+	}
+	if it.is_method {
+		sym := c.table.get_type_symbol(it.receiver.typ)
+		if sym.kind == .interface_ {
+			c.error('interfaces cannot be used as method receiver', it.receiver_pos)
+		}
+		// if sym.has_method(it.name) {
+		// c.warn('duplicate method `$it.name`', it.pos)
+		// }
+	}
+	if !it.is_c {
+		// Make sure all types are valid
+		for arg in it.args {
+			sym := c.table.get_type_symbol(arg.typ)
+			if sym.kind == .placeholder {
+				c.error('unknown type `$sym.name`', it.pos)
+			}
+		}
+	}
+	c.expected_type = table.void_type
+	c.fn_return_type = it.return_type
+	c.stmts(it.stmts)
+	if !it.is_c && !it.is_js && !it.no_body && it.return_type != table.void_type && !c.returns &&
+		it.name !in ['panic', 'exit'] {
+		c.error('missing return at end of function `$it.name`', it.pos)
+	}
+	c.returns = false
+}
diff --git a/vlib/v/parser/fn.v b/vlib/v/parser/fn.v
index 270d7ae2ec..33a1831054 100644
--- a/vlib/v/parser/fn.v
+++ b/vlib/v/parser/fn.v
@@ -255,6 +255,7 @@ fn (mut p Parser) fn_decl() ast.FnDecl {
 			is_generic: is_generic
 			is_pub: is_pub
 			ctdefine: ctdefine
+			mod: p.mod
 		})
 	}
 	// Body
diff --git a/vlib/v/util/scanning.v b/vlib/v/util/scanning.v
index 865ff6907e..9fc7e7e39b 100644
--- a/vlib/v/util/scanning.v
+++ b/vlib/v/util/scanning.v
@@ -3,21 +3,21 @@ module util
 import os
 
 [inline]
-fn is_name_char(c byte) bool {
+pub fn is_name_char(c byte) bool {
 	return (c >= `a` && c <= `z`) || (c >= `A` && c <= `Z`) || c == `_`
 }
 
 [inline]
-fn is_func_char(c byte) bool {
+pub fn is_func_char(c byte) bool {
 	return (c >= `a` && c <= `z`) || (c >= `A` && c <= `Z`) || c == `_` || c.is_digit()
 }
 
 [inline]
-fn is_nl(c byte) bool {
+pub fn is_nl(c byte) bool {
 	return c == `\r` || c == `\n`
 }
 
-fn contains_capital(s string) bool {
+pub fn contains_capital(s string) bool {
 	for c in s {
 		if c >= `A` && c <= `Z` {
 			return true
@@ -28,7 +28,7 @@ fn contains_capital(s string) bool {
 
 // HTTPRequest  bad
 // HttpRequest  good
-fn good_type_name(s string) bool {
+pub fn good_type_name(s string) bool {
 	if s.len < 4 {
 		return true
 	}
diff --git a/vlib/v/util/util.v b/vlib/v/util/util.v
index 68d3c382a6..c54e798308 100644
--- a/vlib/v/util/util.v
+++ b/vlib/v/util/util.v
@@ -222,7 +222,7 @@ fn imax(a, b int) int {
 	}
 }
 
-fn replace_op(s string) string {
+pub fn replace_op(s string) string {
 	last_char := s[s.len - 1]
 	suffix := match last_char {
 		`+` { '_plus' }