[vala/staging] parser: Add support for explicit "unlock" syntax

[Rico Tzschichholz <ricotz src gnome org>]

commit 60ded4b69f0556520696b4b4d575743400d9baa1
Author: Rico Tzschichholz <ricotz ubuntu com>
Date:   Wed Apr 25 16:08:06 2018 +0200

    parser: Add support for explicit "unlock" syntax
    
    By providing more control over the internal support for Mutex creation and
    usage, this allows a more complex resource control while having an explicit
    way to unlock a previously locked lockable.
    
      lock (foo);
      ...
      unlock (foo);
    
    https://bugzilla.gnome.org/show_bug.cgi?id=795545

 tests/Makefile.am                |    1 +
 tests/parser/lock-statement.vala |   19 +++++++++++++++++++
 vala/valaparser.vala             |   22 +++++++++++++++++++++-
 vala/valascanner.vala            |    3 +++
 vala/valatokentype.vala          |    2 ++
 5 files changed, 46 insertions(+), 1 deletions(-)
---
diff --git a/tests/Makefile.am b/tests/Makefile.am
index 64ce795..eb07352 100644
--- a/tests/Makefile.am
+++ b/tests/Makefile.am
@@ -419,6 +419,7 @@ TESTS = \
        parser/function-syntax-error.test \
        parser/inner-array-size.test \
        parser/invalid-brace.test \
+       parser/lock-statement.vala \
        parser/method-no-abstract-override.test \
        parser/method-no-abstract-virtual-override.test \
        parser/method-no-abstract-virtual.test \
diff --git a/tests/parser/lock-statement.vala b/tests/parser/lock-statement.vala
new file mode 100644
index 0000000..65d9d82
--- /dev/null
+++ b/tests/parser/lock-statement.vala
@@ -0,0 +1,19 @@
+class Foo {
+       int lockable;
+
+       public void explicit_unlocking () {
+               lock (lockable);
+               unlock (lockable);
+       }
+
+       public void implicit_unlocking () {
+               lock (lockable) {
+               }
+       }
+}
+
+void main () {
+       var foo = new Foo ();
+       foo.explicit_unlocking ();
+       foo.implicit_unlocking ();
+}
diff --git a/vala/valaparser.vala b/vala/valaparser.vala
index 3df315d..eca5565 100644
--- a/vala/valaparser.vala
+++ b/vala/valaparser.vala
@@ -238,6 +238,7 @@ public class Vala.Parser : CodeVisitor {
                case TokenType.TRUE:
                case TokenType.TRY:
                case TokenType.TYPEOF:
+               case TokenType.UNLOCK:
                case TokenType.UNOWNED:
                case TokenType.USING:
                case TokenType.VAR:
@@ -1576,6 +1577,9 @@ public class Vala.Parser : CodeVisitor {
                                case TokenType.LOCK:
                                        stmt = parse_lock_statement ();
                                        break;
+                               case TokenType.UNLOCK:
+                                       stmt = parse_unlock_statement ();
+                                       break;
                                case TokenType.DELETE:
                                        stmt = parse_delete_statement ();
                                        break;
@@ -1740,6 +1744,7 @@ public class Vala.Parser : CodeVisitor {
                case TokenType.THROW:     return parse_throw_statement ();
                case TokenType.TRY:       return parse_try_statement ();
                case TokenType.LOCK:      return parse_lock_statement ();
+               case TokenType.UNLOCK:    return parse_unlock_statement ();
                case TokenType.DELETE:    return parse_delete_statement ();
                case TokenType.VAR:
                case TokenType.CONST:
@@ -2134,10 +2139,23 @@ public class Vala.Parser : CodeVisitor {
                expect (TokenType.OPEN_PARENS);
                var expr = parse_expression ();
                expect (TokenType.CLOSE_PARENS);
-               var stmt = parse_embedded_statement ("lock", false);
+               Block? stmt = null;
+               if (current () != TokenType.SEMICOLON) {
+                       stmt = parse_embedded_statement ("lock", false);
+               }
                return new LockStatement (expr, stmt, get_src (begin));
        }
 
+       Statement parse_unlock_statement () throws ParseError {
+               var begin = get_location ();
+               expect (TokenType.UNLOCK);
+               expect (TokenType.OPEN_PARENS);
+               var expr = parse_expression ();
+               expect (TokenType.CLOSE_PARENS);
+               expect (TokenType.SEMICOLON);
+               return new UnlockStatement (expr, get_src (begin));
+       }
+
        Statement parse_delete_statement () throws ParseError {
                var begin = get_location ();
                expect (TokenType.DELETE);
@@ -2265,6 +2283,7 @@ public class Vala.Parser : CodeVisitor {
                case TokenType.THROW:
                case TokenType.TRY:
                case TokenType.LOCK:
+               case TokenType.UNLOCK:
                case TokenType.DELETE:
                case TokenType.VAR:
                case TokenType.OP_INC:
@@ -2450,6 +2469,7 @@ public class Vala.Parser : CodeVisitor {
                        case TokenType.SWITCH:
                        case TokenType.THROW:
                        case TokenType.TRY:
+                       case TokenType.UNLOCK:
                        case TokenType.VAR:
                        case TokenType.WHILE:
                        case TokenType.YIELD:
diff --git a/vala/valascanner.vala b/vala/valascanner.vala
index 8b50a59..2cb7050 100644
--- a/vala/valascanner.vala
+++ b/vala/valascanner.vala
@@ -473,6 +473,9 @@ public class Vala.Scanner {
                                        break;
                                }
                                break;
+                       case 'u':
+                               if (matches (begin, "unlock")) return TokenType.UNLOCK;
+                               break;
                        }
                        break;
                case 7:
diff --git a/vala/valatokentype.vala b/vala/valatokentype.vala
index a3867f5..38be631 100644
--- a/vala/valatokentype.vala
+++ b/vala/valatokentype.vala
@@ -143,6 +143,7 @@ public enum Vala.TokenType {
        TRUE,
        TRY,
        TYPEOF,
+       UNLOCK,
        UNOWNED,
        USING,
        VAR,
@@ -275,6 +276,7 @@ public enum Vala.TokenType {
                case TRUE: return "`true'";
                case TRY: return "`try'";
                case TYPEOF: return "`typeof'";
+               case UNLOCK: return "`unlock'";
                case UNOWNED: return "`unowned'";
                case USING: return "`using'";
                case VAR: return "`var'";