From 1b1d17cfb54b13702fbf5e6480d195d786354511 Mon Sep 17 00:00:00 2001
From: Alexander Medvednikov <alexander@vlang.io>
Date: Thu, 5 Nov 2020 08:44:34 +0100
Subject: [PATCH] os: basic proof of concept stdout capture; autofree: small
 fixes

---
 vlib/os/os_nix.c.v | 48 ++++++++++++++++++++++++++++++++++++++++++++++
 vlib/os/os_test.v  | 15 +++++++++++++++
 vlib/v/gen/cgen.v  | 18 ++++++++++-------
 vlib/v/gen/fn.v    | 15 ++++++++++++---
 4 files changed, 86 insertions(+), 10 deletions(-)

diff --git a/vlib/os/os_nix.c.v b/vlib/os/os_nix.c.v
index a46e53394d..97cbdd758d 100644
--- a/vlib/os/os_nix.c.v
+++ b/vlib/os/os_nix.c.v
@@ -159,6 +159,54 @@ pub fn exec(cmd string) ?Result {
 	}
 }
 
+pub struct  Command {
+mut:
+	f voidptr
+pub mut:
+	eof bool
+pub:
+	path string
+	redirect_stdout bool
+}
+
+//pub fn command(cmd Command) Command {
+//}
+
+pub fn (mut c Command) start()? {
+	pcmd := '$c.path 2>&1'
+	c.f = vpopen(pcmd)
+	if isnil(c.f) {
+		return error('exec("$c.path") failed')
+	}
+}
+
+pub fn (mut c Command) read_line() string {
+	buf := [4096]byte{}
+	mut res := strings.new_builder(1024)
+	unsafe {
+		for C.fgets(charptr(buf), 4096, c.f) != 0 {
+			bufbp := byteptr(buf)
+			len := vstrlen(bufbp)
+			for i in 0..len {
+				if int(bufbp[i]) == `\n` {
+					res.write_bytes(bufbp, i)
+					return res.str()
+				}
+			}
+			res.write_bytes(bufbp, len)
+		}
+	}
+	c.eof = true
+	return res.str()
+}
+
+pub fn (c &Command) close()? {
+	exit_code := vpclose(c.f)
+	if exit_code == 127 {
+		return error_with_code('error', 127)
+	}
+}
+
 pub fn symlink(origin string, target string) ?bool {
 	res := C.symlink(charptr(origin.str), charptr(target.str))
 	if res == 0 {
diff --git a/vlib/os/os_test.v b/vlib/os/os_test.v
index 452b9570be..6a81e5bc37 100644
--- a/vlib/os/os_test.v
+++ b/vlib/os/os_test.v
@@ -503,3 +503,18 @@ fn test_write_file_array_structs() {
 	assert rarr.len == maxn
 	// eprintln( rarr.str().replace('\n', ' ').replace('},', '},\n'))
 }
+
+fn test_stdout_capture() {
+	/*
+mut cmd := os.Command{
+	path:'cat'
+	redirect_stdout: true
+}
+cmd.start()
+for !cmd.eof {
+	line := cmd.read_line()
+	println('line="$line"')
+}
+cmd.close()
+*/
+}
diff --git a/vlib/v/gen/cgen.v b/vlib/v/gen/cgen.v
index 28b60e77a0..7f05394c64 100644
--- a/vlib/v/gen/cgen.v
+++ b/vlib/v/gen/cgen.v
@@ -118,7 +118,8 @@ mut:
 	called_fn_name        string
 	cur_mod               string
 	is_js_call            bool // for handling a special type arg #1 `json.decode(User, ...)`
-	nr_vars_to_free       int
+	// nr_vars_to_free       int
+	doing_autofree_tmp    bool
 	inside_lambda         bool
 }
 
@@ -1043,8 +1044,11 @@ fn (mut g Gen) stmt(node ast.Stmt) {
 	// If we have temporary string exprs to free after this statement, do it. e.g.:
 	// `foo('a' + 'b')` => `tmp := 'a' + 'b'; foo(tmp); string_free(&tmp);`
 	if g.pref.autofree {
-		p := node.position()
-		g.autofree_call_postgen(p.pos)
+		// if node is ast.ExprStmt {&& node.expr is ast.CallExpr {
+		if node !is ast.FnDecl {
+			p := node.position()
+			g.autofree_call_postgen(p.pos)
+		}
 	}
 }
 
@@ -1975,13 +1979,13 @@ fn (mut g Gen) autofree_var_call(free_fn_name string, v ast.Var) {
 		// tmp expr vars do not need to be freed again here
 		return
 	}
-	// if v.is_autofree_tmp {
-	// return
-	// }
+	if v.is_autofree_tmp && !g.doing_autofree_tmp {
+		return
+	}
 	if v.typ.is_ptr() {
 		g.writeln('\t${free_fn_name}(${c_name(v.name)}); // autofreed ptr var')
 	} else {
-		g.writeln('\t${free_fn_name}(&${c_name(v.name)}); // autofreed var')
+		g.writeln('\t${free_fn_name}(&${c_name(v.name)}); // autofreed var $g.doing_autofree_tmp')
 	}
 }
 
diff --git a/vlib/v/gen/fn.v b/vlib/v/gen/fn.v
index 853e96f54c..56f9914ee0 100644
--- a/vlib/v/gen/fn.v
+++ b/vlib/v/gen/fn.v
@@ -709,7 +709,7 @@ fn (mut g Gen) autofree_call_pregen(node ast.CallExpr) {
 		g.strs_to_free0 << s
 		// Now free the tmp arg vars right after the function call
 		// g.strs_to_free << t
-		g.nr_vars_to_free++
+		// g.nr_vars_to_free++
 		// g.strs_to_free << 'string_free(&$t);'
 	}
 }
@@ -720,10 +720,12 @@ fn (mut g Gen) autofree_call_postgen(node_pos int) {
 		return
 	}
 	*/
-	// g.writeln('\n/* strs_to_free3: $g.nr_vars_to_free */')
+	/*
+	g.writeln('\n/* strs_to_free3: $g.nr_vars_to_free */')
 	if g.nr_vars_to_free <= 0 {
 		return
 	}
+	*/
 	/*
 	for s in g.strs_to_free {
 		g.writeln('string_free(&$s);')
@@ -734,6 +736,11 @@ fn (mut g Gen) autofree_call_postgen(node_pos int) {
 		g.strs_to_free = []
 	}
 	*/
+	if g.inside_vweb_tmpl {
+		return
+	}
+	g.doing_autofree_tmp = true
+	g.write('/* postgen */')
 	scope := g.file.scope.innermost(node_pos)
 	for _, obj in scope.objects {
 		match mut obj {
@@ -757,11 +764,13 @@ fn (mut g Gen) autofree_call_postgen(node_pos int) {
 				}
 				obj.is_used = true
 				g.autofree_variable(v)
-				g.nr_vars_to_free--
+				// g.nr_vars_to_free--
 			}
 			else {}
 		}
 	}
+	g.write('/* postgen end */')
+	g.doing_autofree_tmp = false
 }
 
 fn (mut g Gen) call_args(node ast.CallExpr) {