From b5108b8065f4eeb9461e2dbc9ddcab8ccc01f0e9 Mon Sep 17 00:00:00 2001
From: Daniel Kang <me@daniel.gs>
Date: Fri, 18 Jan 2019 02:28:58 -0800
Subject: [PATCH] os Process functions

---
 compiler/stdlib/func_typedefs.go |  14 ++++
 compiler/stdlib/os.go            |   7 ++
 compiler/stdlib/os_process.go    | 129 +++++++++++++++++++++++++++++++
 3 files changed, 150 insertions(+)
 create mode 100644 compiler/stdlib/os_process.go

diff --git a/compiler/stdlib/func_typedefs.go b/compiler/stdlib/func_typedefs.go
index 83c540f..022c77f 100644
--- a/compiler/stdlib/func_typedefs.go
+++ b/compiler/stdlib/func_typedefs.go
@@ -34,6 +34,20 @@ func FuncARI(fn func() int) *objects.UserFunction {
 	}
 }
 
+// FuncARB transform a function of 'func() bool' signature
+// into a user function object.
+func FuncARB(fn func() bool) *objects.UserFunction {
+	return &objects.UserFunction{
+		Value: func(args ...objects.Object) (ret objects.Object, err error) {
+			if len(args) != 0 {
+				return nil, objects.ErrWrongNumArguments
+			}
+
+			return &objects.Bool{Value: fn()}, nil
+		},
+	}
+}
+
 // FuncARE transform a function of 'func() error' signature
 // into a user function object.
 func FuncARE(fn func() error) *objects.UserFunction {
diff --git a/compiler/stdlib/os.go b/compiler/stdlib/os.go
index 06aa1d9..660594d 100644
--- a/compiler/stdlib/os.go
+++ b/compiler/stdlib/os.go
@@ -33,6 +33,9 @@ var osModule = map[string]objects.Object{
 	"path_separator":      &objects.Char{Value: os.PathSeparator},
 	"path_list_separator": &objects.Char{Value: os.PathListSeparator},
 	"dev_null":            &objects.String{Value: os.DevNull},
+	"seek_set":            &objects.Int{Value: int64(os.SEEK_SET)},
+	"seek_cur":            &objects.Int{Value: int64(os.SEEK_CUR)},
+	"seek_end":            &objects.Int{Value: int64(os.SEEK_END)},
 	// args() => array(string)
 	"args": &objects.UserFunction{Value: osArgs},
 	// chdir(dir string) => error
@@ -109,6 +112,10 @@ var osModule = map[string]objects.Object{
 	"open": &objects.UserFunction{Value: osOpen},
 	// open_file(name string, flag int, perm int) => imap(file)/error
 	"open_file": &objects.UserFunction{Value: osOpenFile},
+	// find_process(pid int) => imap(process)/error
+	"find_process": &objects.UserFunction{Value: osFindProcess},
+	// start_process(name string, argv array(string), dir string, env array(string)) => imap(process)/error
+	"start_process": &objects.UserFunction{Value: osStartProcess},
 
 	// TODO: implemented more functions
 	//"stdin":         nil,
diff --git a/compiler/stdlib/os_process.go b/compiler/stdlib/os_process.go
new file mode 100644
index 0000000..45872d7
--- /dev/null
+++ b/compiler/stdlib/os_process.go
@@ -0,0 +1,129 @@
+package stdlib
+
+import (
+	"os"
+	"syscall"
+
+	"github.com/d5/tengo/objects"
+)
+
+func osProcessStateImmutableMap(state *os.ProcessState) *objects.ImmutableMap {
+	return &objects.ImmutableMap{
+		Value: map[string]objects.Object{
+			"exited":  FuncARB(state.Exited),
+			"pid":     FuncARI(state.Pid),
+			"string":  FuncARS(state.String),
+			"success": FuncARB(state.Success),
+		},
+	}
+}
+
+func osProcessImmutableMap(proc *os.Process) *objects.ImmutableMap {
+	return &objects.ImmutableMap{
+		Value: map[string]objects.Object{
+			"kill":    FuncARE(proc.Kill),
+			"release": FuncARE(proc.Release),
+			"signal": &objects.UserFunction{
+				Value: func(args ...objects.Object) (ret objects.Object, err error) {
+					if len(args) != 1 {
+						return nil, objects.ErrWrongNumArguments
+					}
+
+					i1, ok := objects.ToInt64(args[0])
+					if !ok {
+						return nil, objects.ErrInvalidTypeConversion
+					}
+
+					return wrapError(proc.Signal(syscall.Signal(i1))), nil
+				},
+			},
+			"wait": &objects.UserFunction{
+				Value: func(args ...objects.Object) (ret objects.Object, err error) {
+					if len(args) != 0 {
+						return nil, objects.ErrWrongNumArguments
+					}
+
+					state, err := proc.Wait()
+					if err != nil {
+						return wrapError(err), nil
+					}
+
+					return osProcessStateImmutableMap(state), nil
+				},
+			},
+		},
+	}
+}
+
+func osFindProcess(args ...objects.Object) (objects.Object, error) {
+	if len(args) != 1 {
+		return nil, objects.ErrWrongNumArguments
+	}
+
+	i1, ok := objects.ToInt(args[0])
+	if !ok {
+		return nil, objects.ErrInvalidTypeConversion
+	}
+
+	proc, err := os.FindProcess(i1)
+	if err != nil {
+		return wrapError(err), nil
+	}
+
+	return osProcessImmutableMap(proc), nil
+}
+
+func osStartProcess(args ...objects.Object) (objects.Object, error) {
+	if len(args) != 4 {
+		return nil, objects.ErrWrongNumArguments
+	}
+
+	name, ok := objects.ToString(args[0])
+	if !ok {
+		return nil, objects.ErrInvalidTypeConversion
+	}
+
+	argv, err := stringArray(args[1])
+	if err != nil {
+		return nil, err
+	}
+
+	dir, ok := objects.ToString(args[2])
+	if !ok {
+		return nil, objects.ErrInvalidTypeConversion
+	}
+
+	env, err := stringArray(args[3])
+	if err != nil {
+		return nil, err
+	}
+
+	proc, err := os.StartProcess(name, argv, &os.ProcAttr{
+		Dir: dir,
+		Env: env,
+	})
+	if err != nil {
+		return wrapError(err), nil
+	}
+
+	return osProcessImmutableMap(proc), nil
+}
+
+func stringArray(o objects.Object) ([]string, error) {
+	arr, ok := o.(*objects.Array)
+	if !ok {
+		return nil, objects.ErrInvalidTypeConversion
+	}
+
+	var sarr []string
+	for _, elem := range arr.Value {
+		str, ok := elem.(*objects.String)
+		if !ok {
+			return nil, objects.ErrInvalidTypeConversion
+		}
+
+		sarr = append(sarr, str.Value)
+	}
+
+	return sarr, nil
+}