v2: enhance version with current git commit hash. Cleanup redundant code.

cmd/tools/vrepl.v

@@ -9,6 +9,7 @@ import (
 	term
 	readline
 	os.cmdline
+	v.util
 )
 
 struct Repl {
@@ -63,8 +64,7 @@ fn (r &Repl) function_call(line string) bool {
 }
 
 pub fn repl_help() {
-	version := v_version()
-	println(version)
+	println(util.full_v_version())
 	println('
   help                   Displays this information.
   Ctrl-C, Ctrl-D, exit   Exits the REPL.
@@ -73,8 +73,7 @@ pub fn repl_help() {
 }
 
 pub fn run_repl(workdir string, vrepl_prefix string) []string {
-	version := v_version()
-	println(version)
+	println(util.full_v_version())
 	println('Use Ctrl-C or `exit` to exit')
 
 	file := os.join_path(workdir, '.${vrepl_prefix}vrepl.v')
@@ -233,9 +232,3 @@ pub fn rerror(s string) {
 	os.flush()
 	exit(1)
 }
-
-fn v_version() string {
-	vexe := os.getenv('VEXE')
-	vversion_res := os.exec('$vexe -version') or { panic('"$vexe -version" is not working') }
-	return vversion_res.output
-}

cmd/v/internal/compile/cc.v

@@ -7,16 +7,12 @@ import (
 	os
 	time
 	v.pref
+	v.util
 	term
 )
 
- pub const (
-         v_version = '0.1.26'
- )
-
-
 const (
-v_modules_path = pref.default_module_path
+	v_modules_path = pref.default_module_path
 )
 
 fn todo() {
@@ -380,7 +376,7 @@ start:
 ==================
 C error. This should never happen.
 
-V compiler version: V $v_version $vhash()
+V compiler version: ${util.full_v_version()}
 Host OS: ${pref.get_host_os().str()}
 Target OS: $v.pref.os.str()
 
@@ -626,11 +622,3 @@ fn error_context_lines(text, keyword string, before, after int) []string {
 	idx_e := if idx_s + after < lines.len { idx_s + after } else { lines.len }
 	return lines[idx_s..idx_e]
 }
-
-fn vhash() string {
-        mut buf := [50]byte
-        buf[0] = 0
-        C.snprintf(charptr(buf), 50, '%s', C.V_COMMIT_HASH)
-        return tos_clone(buf)
-}
-

cmd/v/v.v

@@ -11,6 +11,7 @@ import (
 	v.table
 	v.doc
 	v.pref
+	v.util
 )
 
 const (
@@ -23,11 +24,6 @@ const (
 	'setup-freetype']
 )
 
- pub const (
-         v_version = '0.1.26'
- )
-
-
 fn main() {
 	prefs := flag.MainCmdPreferences{}
 	values := flag.parse_main_cmd(os.args, parse_flags, prefs) or {
@@ -36,7 +32,7 @@ fn main() {
 		exit(1)
 	}
 	if prefs.verbosity.is_higher_or_equal(.level_two) {
-		println('V $v_version $vhash()')
+		println(util.full_v_version())
 	}
 	if prefs.verbosity.is_higher_or_equal(.level_three) {
 		println('Parsed preferences: ')
@@ -126,18 +122,10 @@ fn main() {
 }
 
 fn print_version_and_exit() {
-	version_hash := vhash()
-	println('V $v_version $version_hash')
+	println(util.full_v_version())
 	exit(0)
 }
 
-fn vhash() string {
-        mut buf := [50]byte
-        buf[0] = 0
-        C.snprintf(charptr(buf), 50, '%s', C.V_COMMIT_HASH)
-        return tos_clone(buf)
-}
-
 fn invoke_help_and_exit(remaining []string) {
 	match remaining.len {
 		0, 1 {

vlib/v/gen/cgen.v

@@ -7,6 +7,7 @@ import (
 	v.depgraph
 	v.token
 	v.pref
+	v.util
 	term
 )
 
@@ -98,7 +99,13 @@ pub fn cgen(files []ast.File, table &table.Table, pref &pref.Preferences) string
 	if g.is_test {
 		g.write_tests_main()
 	}
-	return c_commit_hash_default + g.typedefs.str() + g.definitions.str() + g.out.str()
+	return g.hashes() + g.typedefs.str() + g.definitions.str() + g.out.str()
+}
+
+pub fn (g &Gen) hashes() string {
+	mut res := c_commit_hash_default.replace('@@@', util.vhash() )
+	res += c_current_commit_hash_default.replace('@@@', util.githash( g.pref.building_v ) )
+	return res
 }
 
 pub fn (g mut Gen) init() {

vlib/v/gen/cheaders.v

@@ -1,12 +1,27 @@
 module gen
 
+import v.util
+
+// NB: @@@ here serve as placeholders.
+// They will be replaced with correct strings
+// for each constant, during C code generation.
+
 const (
+	// V_COMMIT_HASH is generated by cmd/tools/gen_vc.v .
 	c_commit_hash_default = '
 #ifndef V_COMMIT_HASH
-#define V_COMMIT_HASH "$vhash()"
+#define V_COMMIT_HASH "@@@"
 #endif
 
 '
+	// V_CURRENT_COMMIT_HASH is updated, when V is rebuilt inside a git repo.
+	c_current_commit_hash_default = '
+#ifndef V_CURRENT_COMMIT_HASH
+#define V_CURRENT_COMMIT_HASH "@@@"
+#endif
+
+'
+
 	c_common_macros = '
 #define EMPTY_STRUCT_DECLARATION
 #define EMPTY_STRUCT_INITIALIZATION 0

vlib/v/scanner/scanner.v

@@ -7,6 +7,7 @@ import (
 	os
 	v.token
 	v.pref
+	v.util
 )
 
 const (
@@ -593,7 +594,7 @@ pub fn (s mut Scanner) scan() token.Token {
 				return s.new_token(.string, (s.current_column()).str())
 			}
 			if name == 'VHASH' {
-				return s.new_token(.string, vhash())
+				return s.new_token(.string, util.vhash())
 			}
 			if !token.is_key(name) {
 				s.error('@ must be used before keywords (e.g. `@type string`)')
@@ -1033,13 +1034,6 @@ pub fn verror(s string) {
 	exit(1)
 }
 
-pub fn vhash() string {
-	mut buf := [50]byte
-	buf[0] = 0
-	C.snprintf(charptr(buf), 50, '%s', C.V_COMMIT_HASH)
-	return tos_clone(buf)
-}
-
 pub fn cescaped_path(s string) string {
 	return s.replace('\\', '\\\\')
 }

vlib/v/util/util.v

@@ -0,0 +1,84 @@
+// Copyright (c) 2019-2020 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 util
+
+import os
+
+pub const (
+	v_version = '0.1.26'
+)
+
+// vhash() returns the build string C.V_COMMIT_HASH . See cmd/tools/gen_vc.v .
+pub fn vhash() string {
+	mut buf := [50]byte
+	buf[0] = 0
+	C.snprintf(charptr(buf), 50, '%s', C.V_COMMIT_HASH)
+	return tos_clone(buf)
+}
+
+pub fn full_hash() string {
+	build_hash := vhash()
+	current_hash := githash(false)
+	final_hash := if build_hash == current_hash {
+		build_hash
+	} else {
+		'${build_hash}.${current_hash}'
+	}
+	return final_hash
+}
+
+// full_v_version() returns the full version of the V compiler
+pub fn full_v_version() string {
+	return 'V ${v_version} ${full_hash()}'
+}
+
+// githash(x) returns the current git commit hash.
+// When x is false, it is very fast - it just returns a predefined C constant.
+// When x is true, it tries to get the current commit hash, by parsing the
+// relevant files in the .git/ folder, or if that is not possible
+// for example when using a V from a V binary release, that does not have .git/
+// defaults to getting the predefined C constant again.
+// NB: githash(true) must be called only when v detects that it builds itself.
+// For all other programs, githash(false) should be used.
+pub fn githash(should_get_from_filesystem bool) string {
+	for {
+		// The `for` construct here is used as a goto substitute.
+		// The code in this function will break out of the `for`
+		// if it detects an error and can not continue.
+		if should_get_from_filesystem {
+			vexe := os.getenv('VEXE')
+			vroot := os.dir(vexe)
+			// .git/HEAD
+			git_head_file := os.join_path(vroot, '.git', 'HEAD')
+			if !os.exists( git_head_file ) {
+				break
+			}
+			// 'ref: refs/heads/master' ... the current branch name
+			head_content := os.read_file(git_head_file) or {
+				break
+			}
+			gcbranch_rel_path := head_content.replace('ref: ', '').trim_space()
+			gcbranch_file := os.join_path(vroot, '.git', gcbranch_rel_path)
+			// .git/refs/heads/master
+			if !os.exists( gcbranch_file ) {
+				break
+			}
+			// get the full commit hash contained in the ref heads file
+			current_branch_hash := os.read_file( gcbranch_file ) or {
+				break
+			}
+			desired_hash_length := 7
+			if current_branch_hash.len > desired_hash_length {
+				return current_branch_hash[0..desired_hash_length]
+			}
+		}
+		break
+	}
+	// TODO: use C.V_CURRENT_COMMIT_HASH at stage 2, after v.c is regenerated
+	// mut buf := [50]byte
+	// buf[0] = 0
+	// C.snprintf(charptr(buf), 50, '%s', C.V_CURRENT_COMMIT_HASH)
+	// return tos_clone(buf)
+	return 'unknown'
+}