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/* valalockstatement.vala
*
* Copyright (C) 2009 Jiří Zárevúcky
* Copyright (C) 2006-2010 Jürg Billeter
* Copyright (C) 2006-2007 Raffaele Sandrini
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*
* Authors:
* Raffaele Sandrini <raffaele@sandrini.ch>
* Jiří Zárevúcky <zarevucky.jiri@gmail.com>
*/
using GLib;
/**
* Represents a lock statement.
*
* {{{ lock (foo); }}} or {{{ lock (foo) { ... } }}}
*
* If the statement is empty, the mutex remains locked until a corresponding
* {@link Vala.UnlockStatement} occurs. Otherwise it's translated into a
* try/finally statement which unlocks the mutex after the block is finished.
*/
public class Vala.LockStatement : CodeNode, Statement {
/**
* Expression representing the resource to be locked.
*/
public Expression resource {
get { return _resource; }
private set {
_resource = value;
_resource.parent_node = this;
}
}
/**
* The statement during its execution the resource is locked.
*/
public Block? body {
get { return _body; }
private set {
_body = value;
if (_body != null) {
_body.parent_node = this;
}
}
}
private Expression _resource;
private Block _body;
public LockStatement (Expression resource, Block? body, SourceReference? source_reference = null) {
this.body = body;
this.source_reference = source_reference;
this.resource = resource;
}
public override void accept (CodeVisitor visitor) {
resource.accept (visitor);
if (body != null) {
body.accept (visitor);
}
visitor.visit_lock_statement (this);
}
public override void replace_expression (Expression old_node, Expression new_node) {
if (resource == old_node) {
resource = new_node;
}
}
public override bool check (CodeContext context) {
if (body != null) {
if (!body.check (context)) {
return false;
}
// if the statement isn't empty, it is converted into a try statement
var fin_body = new Block (source_reference);
fin_body.add_statement (new UnlockStatement (resource, source_reference));
var try_stmt = new TryStatement (body, fin_body, source_reference);
if (body.tree_can_fail) {
var catch_body = new Block (source_reference);
catch_body.add_statement (new ThrowStatement (new ReferenceTransferExpression (new MemberAccess.simple ("_lock_error_")), source_reference));
var catch_clause = new CatchClause (new ErrorType (null, null), "_lock_error_", catch_body, source_reference);
catch_clause.error_type.value_owned = true;
try_stmt.add_catch_clause (catch_clause);
}
var block = new Block (source_reference);
block.add_statement (new LockStatement (resource, null, source_reference));
block.add_statement (try_stmt);
var parent_block = (Block) parent_node;
parent_block.replace_statement (this, block);
return block.check (context);
}
if (checked) {
return !error;
}
checked = true;
resource.check (context);
/* resource must be a member access and denote a Lockable */
if (!(resource is MemberAccess && resource.symbol_reference is Lockable)) {
error = true;
resource.error = true;
Report.error (resource.source_reference, "Expression is either not a member access or does not denote a lockable member");
return false;
}
/* parent symbol must be the current class */
if (resource.symbol_reference.parent_symbol != context.analyzer.current_class) {
error = true;
resource.error = true;
Report.error (resource.source_reference, "Only members of the current class are lockable");
return false;
}
/* parent class must not be compact */
if (context.analyzer.current_class.is_compact) {
error = true;
resource.error = true;
Report.error (resource.source_reference, "Only members of the non-compact classes are lockable");
return false;
}
((Lockable) resource.symbol_reference).lock_used = true;
return !error;
}
public override void emit (CodeGenerator codegen) {
resource.emit (codegen);
codegen.visit_lock_statement (this);
}
}
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