D-Scanner/src/dscanner/analysis/final_attribute.d

418 lines
9.8 KiB
D

// Copyright Basile Burg 2017.
// Distributed under the Boost Software License, Version 1.0.
// (See accompanying file LICENSE_1_0.txt or copy at
// http://www.boost.org/LICENSE_1_0.txt)
module dscanner.analysis.final_attribute;
import dscanner.analysis.base;
import dscanner.analysis.helpers;
import dparse.ast;
import dparse.lexer;
/**
* Checks for useless usage of the final attribute.
*
* There are several cases where the compiler allows them even if it's a noop.
*/
final class FinalAttributeChecker : BaseAnalyzer
{
private:
enum string KEY = "dscanner.useless.final";
enum string MSGB = "Useless final attribute, %s";
static struct MESSAGE
{
static immutable struct_i = "structs cannot be subclassed";
static immutable union_i = "unions cannot be subclassed";
static immutable class_t = "templated functions declared within a class are never virtual";
static immutable class_p = "private functions declared within a class are never virtual";
static immutable class_f = "functions declared within a final class are never virtual";
static immutable class_s = "static functions are never virtual";
static immutable interface_t = "templated functions declared within an interface are never virtual";
static immutable struct_f = "functions declared within a struct are never virtual";
static immutable union_f = "functions declared within an union are never virtual";
static immutable func_n = "nested functions are never virtual";
static immutable func_g = "global functions are never virtual";
}
enum Parent
{
module_,
struct_,
union_,
class_,
function_,
interface_
}
bool[] _private;
bool _finalAggregate;
bool _alwaysStatic;
bool _blockStatic;
Parent _parent = Parent.module_;
void addError(T)(T t, string msg)
{
import std.format : format;
const size_t lne = t.name.line;
const size_t col = t.name.column;
addErrorMessage(lne, col, KEY, MSGB.format(msg));
}
public:
alias visit = BaseAnalyzer.visit;
///
this(string fileName, bool skipTests = false)
{
super(fileName, null, skipTests);
_private.length = 1;
}
override void visit(const(StructDeclaration) sd)
{
const Parent saved = _parent;
_parent = Parent.struct_;
_private.length += 1;
_alwaysStatic = false;
sd.accept(this);
_private.length -= 1;
_parent = saved;
}
override void visit(const(InterfaceDeclaration) id)
{
const Parent saved = _parent;
_parent = Parent.interface_;
_private.length += 1;
_alwaysStatic = false;
id.accept(this);
_private.length -= 1;
_parent = saved;
}
override void visit(const(UnionDeclaration) ud)
{
const Parent saved = _parent;
_parent = Parent.union_;
_private.length += 1;
_alwaysStatic = false;
ud.accept(this);
_private.length -= 1;
_parent = saved;
}
override void visit(const(ClassDeclaration) cd)
{
const Parent saved = _parent;
_parent = Parent.class_;
_private.length += 1;
_alwaysStatic = false;
cd.accept(this);
_private.length -= 1;
_parent = saved;
}
override void visit(const(MixinTemplateDeclaration) mtd)
{
// can't really know where it'll be mixed (class |final class | struct ?)
}
override void visit(const(TemplateDeclaration) mtd)
{
// regular template are also mixable
}
override void visit(const(AttributeDeclaration) decl)
{
if (_parent == Parent.class_ && decl.attribute &&
decl.attribute.attribute == tok!"static")
_alwaysStatic = true;
}
override void visit(const(Declaration) d)
{
import std.algorithm.iteration : filter;
import std.algorithm.searching : canFind;
const Parent savedParent = _parent;
bool undoBlockStatic;
if (_parent == Parent.class_ && d.attributes &&
d.attributes.canFind!(a => a.attribute == tok!"static"))
{
_blockStatic = true;
undoBlockStatic = true;
}
const bool wasFinalAggr = _finalAggregate;
scope(exit)
{
d.accept(this);
_parent = savedParent;
if (undoBlockStatic)
_blockStatic = false;
_finalAggregate = wasFinalAggr;
}
if (!d.attributeDeclaration &&
!d.classDeclaration &&
!d.structDeclaration &&
!d.unionDeclaration &&
!d.interfaceDeclaration &&
!d.functionDeclaration)
return;
if (d.attributeDeclaration && d.attributeDeclaration.attribute)
{
const tp = d.attributeDeclaration.attribute.attribute.type;
_private[$-1] = isProtection(tp) & (tp == tok!"private");
}
const bool isFinal = d.attributes
.canFind!(a => a.attribute.type == tok!"final");
const bool isStaticOnce = d.attributes
.canFind!(a => a.attribute.type == tok!"static");
// determine if private
const bool changeProtectionOnce = d.attributes
.canFind!(a => a.attribute.type.isProtection);
const bool isPrivateOnce = d.attributes
.canFind!(a => a.attribute.type == tok!"private");
bool isPrivate;
if (isPrivateOnce)
isPrivate = true;
else if (_private[$-1] && !changeProtectionOnce)
isPrivate = true;
// check final aggregate type
if (d.classDeclaration || d.structDeclaration || d.unionDeclaration)
{
_finalAggregate = isFinal;
if (_finalAggregate && savedParent == Parent.module_)
{
if (d.structDeclaration)
addError(d.structDeclaration, MESSAGE.struct_i);
else if (d.unionDeclaration)
addError(d.unionDeclaration, MESSAGE.union_i);
}
}
if (!d.functionDeclaration)
return;
// check final functions
_parent = Parent.function_;
const(FunctionDeclaration) fd = d.functionDeclaration;
if (isFinal) final switch(savedParent)
{
case Parent.class_:
if (fd.templateParameters)
addError(fd, MESSAGE.class_t);
if (isPrivate)
addError(fd, MESSAGE.class_p);
else if (isStaticOnce || _alwaysStatic || _blockStatic)
addError(fd, MESSAGE.class_s);
else if (_finalAggregate)
addError(fd, MESSAGE.class_f);
break;
case Parent.interface_:
if (fd.templateParameters)
addError(fd, MESSAGE.interface_t);
break;
case Parent.struct_:
addError(fd, MESSAGE.struct_f);
break;
case Parent.union_:
addError(fd, MESSAGE.union_f);
break;
case Parent.function_:
addError(fd, MESSAGE.func_n);
break;
case Parent.module_:
addError(fd, MESSAGE.func_g);
break;
}
}
}
@system unittest
{
import dscanner.analysis.config : StaticAnalysisConfig, Check, disabledConfig;
import dscanner.analysis.helpers : assertAnalyzerWarnings;
import std.stdio : stderr;
import std.format : format;
StaticAnalysisConfig sac = disabledConfig();
sac.final_attribute_check = Check.enabled;
// pass
assertAnalyzerWarnings(q{
void foo(){}
}, sac);
assertAnalyzerWarnings(q{
void foo(){void foo(){}}
}, sac);
assertAnalyzerWarnings(q{
struct S{}
}, sac);
assertAnalyzerWarnings(q{
union U{}
}, sac);
assertAnalyzerWarnings(q{
class Foo{public final void foo(){}}
}, sac);
assertAnalyzerWarnings(q{
final class Foo{static struct Bar{}}
}, sac);
assertAnalyzerWarnings(q{
class Foo{private: public final void foo(){}}
}, sac);
assertAnalyzerWarnings(q{
class Foo{private: public: final void foo(){}}
}, sac);
assertAnalyzerWarnings(q{
class Foo{private: public: final void foo(){}}
}, sac);
assertAnalyzerWarnings(q{
class Impl
{
private:
static if (true)
{
protected final void _wrap_getSource() {}
}
}
}, sac);
assertAnalyzerWarnings(q{
mixin template Impl()
{
protected final void mixin_template_can() {}
}
}, sac);
// fail
assertAnalyzerWarnings(q{
final void foo(){} // [warn]: %s
}c.format(
FinalAttributeChecker.MSGB.format(FinalAttributeChecker.MESSAGE.func_g)
), sac);
assertAnalyzerWarnings(q{
void foo(){final void foo(){}} // [warn]: %s
}c.format(
FinalAttributeChecker.MSGB.format(FinalAttributeChecker.MESSAGE.func_n)
), sac);
assertAnalyzerWarnings(q{
void foo()
{
static if (true)
final class A{ private: final protected void foo(){}} // [warn]: %s
}
}c.format(
FinalAttributeChecker.MSGB.format(FinalAttributeChecker.MESSAGE.class_f)
), sac);
assertAnalyzerWarnings(q{
final struct Foo{} // [warn]: %s
}c.format(
FinalAttributeChecker.MSGB.format(FinalAttributeChecker.MESSAGE.struct_i)
), sac);
assertAnalyzerWarnings(q{
final union Foo{} // [warn]: %s
}c.format(
FinalAttributeChecker.MSGB.format(FinalAttributeChecker.MESSAGE.union_i)
), sac);
assertAnalyzerWarnings(q{
class Foo{private final void foo(){}} // [warn]: %s
}c.format(
FinalAttributeChecker.MSGB.format(FinalAttributeChecker.MESSAGE.class_p)
), sac);
assertAnalyzerWarnings(q{
class Foo{private: final void foo(){}} // [warn]: %s
}c.format(
FinalAttributeChecker.MSGB.format(FinalAttributeChecker.MESSAGE.class_p)
), sac);
assertAnalyzerWarnings(q{
interface Foo{final void foo(T)(){}} // [warn]: %s
}c.format(
FinalAttributeChecker.MSGB.format(FinalAttributeChecker.MESSAGE.interface_t)
), sac);
assertAnalyzerWarnings(q{
final class Foo{final void foo(){}} // [warn]: %s
}c.format(
FinalAttributeChecker.MSGB.format(FinalAttributeChecker.MESSAGE.class_f)
), sac);
assertAnalyzerWarnings(q{
private: final class Foo {public: private final void foo(){}} // [warn]: %s
}c.format(
FinalAttributeChecker.MSGB.format(FinalAttributeChecker.MESSAGE.class_p)
), sac);
assertAnalyzerWarnings(q{
class Foo {final static void foo(){}} // [warn]: %s
}c.format(
FinalAttributeChecker.MSGB.format(FinalAttributeChecker.MESSAGE.class_s)
), sac);
assertAnalyzerWarnings(q{
class Foo
{
void foo(){}
static: final void foo(){} // [warn]: %s
}
}c.format(
FinalAttributeChecker.MSGB.format(FinalAttributeChecker.MESSAGE.class_s)
), sac);
assertAnalyzerWarnings(q{
class Foo
{
void foo(){}
static{ final void foo(){}} // [warn]: %s
void foo(){}
}
}c.format(
FinalAttributeChecker.MSGB.format(FinalAttributeChecker.MESSAGE.class_s)
), sac);
assertAnalyzerWarnings(q{
class Statement
{
final class UsesEH{}
final void comeFrom(){}
}
}, sac);
stderr.writeln("Unittest for FinalAttributeChecker passed.");
}