skia2/include/sksl/DSLFunction.h
Ethan Nicholas 80f6235688 Fixed an issue with passing DSLVar as a DSL function parameter
DSLVar is normally implicitly converted to DSLExpression wherever it is
used, but the naively template-ized nature of DSLFunction::operator()
meant that it was accepting DSLVar parameters directly. Since DSLVar is
non-copyable, this meant DSLVar couldn't be passed directly to a DSL
function.

The smarter templates in this change are able to pass DSLVar by
reference.

Change-Id: Id04531f909cefd29b377c46e37fc4525bb29953c
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/394161
Commit-Queue: Ethan Nicholas <ethannicholas@google.com>
Reviewed-by: John Stiles <johnstiles@google.com>
2021-04-09 17:13:27 +00:00

88 lines
2.4 KiB
C++

/*
* Copyright 2021 Google LLC.
*
* Use of this source code is governed by a BSD-style license that can be
* found in the LICENSE file.
*/
#ifndef SKSL_DSL_FUNCTION
#define SKSL_DSL_FUNCTION
#include "include/sksl/DSLBlock.h"
#include "include/sksl/DSLExpression.h"
#include "include/sksl/DSLType.h"
#include "include/sksl/DSLVar.h"
namespace SkSL {
class Block;
class FunctionDeclaration;
class Variable;
namespace dsl {
class DSLType;
class DSLFunction {
public:
template<class... Parameters>
DSLFunction(const DSLType& returnType, const char* name, Parameters&... parameters)
: fReturnType(&returnType.skslType()) {
std::vector<DSLVar*> parameterArray;
parameterArray.reserve(sizeof...(parameters));
// in C++17, we could just do:
// (parameterArray.push_back(&parameters), ...);
int unused[] = {0, (static_cast<void>(parameterArray.push_back(&parameters)), 0)...};
static_cast<void>(unused);
this->init(returnType, name, std::move(parameterArray));
}
virtual ~DSLFunction() = default;
template<class... Stmt>
void define(Stmt... stmts) {
DSLBlock block = DSLBlock(DSLStatement(std::move(stmts))...);
this->define(std::move(block));
}
void define(DSLBlock block);
template<class... Args>
DSLExpression operator()(Args&&... args) {
SkTArray<DSLExpression> argArray;
argArray.reserve_back(sizeof...(args));
this->collectArgs(argArray, std::forward<Args>(args)...);
return this->call(std::move(argArray));
}
private:
void collectArgs(SkTArray<DSLExpression>& args) {}
template<class... RemainingArgs>
void collectArgs(SkTArray<DSLExpression>& args, DSLVar& var, RemainingArgs&&... remaining) {
args.push_back(var);
collectArgs(args, std::forward<RemainingArgs>(remaining)...);
}
template<class... RemainingArgs>
void collectArgs(SkTArray<DSLExpression>& args, DSLExpression expr,
RemainingArgs&&... remaining) {
args.push_back(std::move(expr));
collectArgs(args, std::forward<RemainingArgs>(remaining)...);
}
void init(const DSLType& returnType, const char* name, std::vector<DSLVar*> params);
DSLExpression call(SkTArray<DSLExpression> args);
const SkSL::Type* fReturnType;
const SkSL::FunctionDeclaration* fDecl;
};
} // namespace dsl
} // namespace SkSL
#endif