compiler: support storing temporary files under TMPDIR/v/

Fix for filepath.join not \0 terminating its result

vlib/compiler/main.v

@@ -799,6 +799,7 @@ pub fn new_v(args[]string) &V {
 	vgen_buf.writeln('module vgen\nimport strings')
 
 	joined_args := args.join(' ')
+		
 	target_os := get_arg(joined_args, 'os', '')
 	comptime_define := get_arg(joined_args, 'd', '')
 	//println('comptimedefine=$comptime_define')
@@ -930,8 +931,8 @@ pub fn new_v(args[]string) &V {
 		println('Go to https://vlang.io to install V.')
 		exit(1)
 	}
-	// println('out_name:$out_name')
-	mut out_name_c := os.realpath('${out_name}.tmp.c')
+
+	mut out_name_c := get_vtmp_filename( out_name, '.tmp.c')
 
 	cflags := get_cmdline_cflags(args)
 
@@ -978,7 +979,7 @@ pub fn new_v(args[]string) &V {
 		println('C compiler=$pref.ccompiler')
 	}
 	if pref.is_so {
-		out_name_c = out_name.all_after(os.path_separator) + '_shared_lib.c'
+		out_name_c = get_vtmp_filename( out_name, '.tmp.so.c')
 	}
 	$if !linux {
 		if pref.is_bare && !out_name.ends_with('.c') {

vlib/compiler/vhelp.v

@@ -28,6 +28,9 @@ pub const (
    You can set it like this: `export VFLAGS="-cc clang -debug"` on *nix,
    `set VFLAGS=-cc msvc` on Windows.
 
+   V respects the TMPDIR environment variable, and will put .tmp.c files in TMPDIR/v/ .
+   If you have not set it, a suitable platform specific folder (like /tmp) will be used.
+
 Options/commands:
   -h, help          Display this information.
   -o <file>         Write output to <file>.

vlib/compiler/vtmp.v

@@ -0,0 +1,21 @@
+// Copyright (c) 2019 Alexander Medvednikov. All rights reserved.
+// Use of this source code is governed by an MIT license
+// that can be found in the LICENSE file.
+
+module compiler
+
+import os
+import filepath
+
+pub fn get_vtmp_folder() string {
+	vtmp := filepath.join(os.tmpdir(),'v')
+	if !os.dir_exists( vtmp ) {
+		os.mkdir(vtmp)
+	}
+	return vtmp
+}
+
+pub fn get_vtmp_filename(base_file_name string, postfix string) string {
+	vtmp := get_vtmp_folder()
+	return os.realpath( filepath.join(vtmp, os.filename( base_file_name ) + postfix) )
+}

vlib/filepath/filepath.v

@@ -2,7 +2,6 @@ module filepath
 
 import(
 	os
-	strings
 )
 
 // return the extension in the file `path`
@@ -26,11 +25,8 @@ pub fn is_abs(path string) bool {
 // pass directories as parameters, returns path as string 
 // TODO use []string.join once ...string becomes "[]string"
 pub fn join(base string, dirs ...string) string {
-	mut path := strings.new_builder(50)
-	path.write(base.trim_right('\\/'))
-	for d in dirs {
-		path.write(os.path_separator)
-		path.write(d)
-	}
-	return path.str()
+	mut result := []string
+	result << base.trim_right('\\/')
+	for d in dirs {	result << d	}
+	return result.join( os.path_separator )
 }

vlib/os/os.v

@@ -145,17 +145,26 @@ pub fn cp(old, new string) ?bool {
 	}
 }
 
-pub fn cp_r(source_path, dest_path string, overwrite bool) ?bool{
+pub fn cp_r(osource_path, odest_path string, overwrite bool) ?bool{
+	source_path := os.realpath( osource_path )
+	dest_path := os.realpath( odest_path )
 	if !os.file_exists(source_path) {
 		return error('Source path doesn\'t exist')
 	}
 	//single file copy
 	if !os.is_dir(source_path) {
 		adjasted_path := if os.is_dir(dest_path) {
-			filepath.join(dest_path, os.basedir(source_path)) } else { dest_path }
+			filepath.join(dest_path, os.filename(source_path)) 
+		} else { 
+			dest_path 
+		}
 		if os.file_exists(adjasted_path) {
-			if overwrite { os.rm(adjasted_path) }
-			else { return error('Destination file path already exist') }
+			if overwrite {
+				os.rm(adjasted_path) 
+			}
+			else { 
+				return error('Destination file path already exist') 
+			}
 		}
 		os.cp(source_path, adjasted_path) or { return error(err) }
 		return true
@@ -558,7 +567,7 @@ pub fn basedir(path string) string {
 	if pos == -1 {
 		return path
 	}
-	return path[..pos + 1]
+	return path[..pos ] // NB: *without* terminating /
 }
 
 pub fn filename(path string) string {
@@ -835,10 +844,6 @@ pub fn realpath(fpath string) string {
 		res = int( !isnil(C._fullpath( fullpath, fpath.str, MAX_PATH )) )
 	}
 	$else{
-		if fpath.len != strlen(fpath.str) {
-			l := strlen(fpath.str)
-			println('FIXME realpath diff len $fpath.len strlen=$l')
-		}	
 		ret := C.realpath(fpath.str, fullpath)
 		if ret == 0 {
 			return fpath
@@ -965,3 +970,31 @@ pub fn join(base string, dirs ...string) string {
 	println('use filepath.join')
 	return filepath.join(base, dirs)
 }
+
+// tmpdir returns the path to a folder, that is suitable for storing temporary files
+pub fn tmpdir() string {
+	mut path := os.getenv('TMPDIR')
+	$if linux {
+		if path == '' { path = '/tmp' }
+	}
+	$if mac {
+		/*
+		if path == '' {
+			// TODO untested
+			path = C.NSTemporaryDirectory() 
+		}
+        */
+		if path == '' {	path = '/tmp' }
+	}
+	$if windows {
+		if path == '' {
+			// TODO see Qt's implementation?
+			// https://doc.qt.io/qt-5/qdir.html#tempPath
+			// https://github.com/qt/qtbase/blob/e164d61ca8263fc4b46fdd916e1ea77c7dd2b735/src/corelib/io/qfilesystemengine_win.cpp#L1275
+			path = os.getenv('TEMP')
+			if path == '' {	path = os.getenv('TMP')	}
+			if path == '' {	path = 'C:/tmp'	}
+		}
+	}
+	return path
+}

vlib/os/os_test.v

@@ -152,6 +152,24 @@ fn test_cp_r() {
   os.cp_r('ex', './', true) or { panic(err) }
 }
 
+fn test_tmpdir(){
+	t := os.tmpdir()
+	assert t.len > 0
+	assert os.is_dir(t)
+	
+	tfile := t + os.path_separator + 'tmpfile.txt'
+	
+	os.rm(tfile) // just in case
+	
+	tfile_content := 'this is a temporary file'
+	os.write_file(tfile, tfile_content)
+	
+	tfile_content_read := os.read_file(tfile) or { panic(err) }
+	assert tfile_content_read == tfile_content
+	
+	os.rm(tfile)
+}
+
 //fn test_fork() {
 //  pid := os.fork()
 //  if pid == 0 {
@@ -179,7 +197,6 @@ fn test_zzz_cleanup(){
 	cleanup_leftovers() assert true
 }
 
-
 // this function is called by both test_aaa_setup & test_zzz_cleanup
 // it ensures that os tests do not polute the filesystem with leftover
 // files so that they can be run several times in a row.