Files
CMake/Source/cmConstStack.h
Matthew Woehlke f2bdc2176f cmStack: New, mutable stack class
We would like to record additional information in the find-package
stack, but we don't have the information at the point a stack entry is
created. The most sane way to handle this appears to be making the stack
mutable, at least under specific circumstances. To facilitate this, we
need a mutable stack type.

Refactor cmConstStack into cmStack, with the ability to either allow or
forbid mutation of its data. Re-add cmConstStack as a type alias.

This doesn't yet allow mutating cmFindPackageStack, but it's a necessary
step toward being able to do so.
2025-07-30 10:11:36 -04:00

40 lines
1.1 KiB
C++

/* Distributed under the OSI-approved BSD 3-Clause License. See accompanying
file LICENSE.rst or https://cmake.org/licensing for details. */
#pragma once
#include "cmConfigure.h" // IWYU pragma: keep
#include <memory>
/** Base class template for CRTP to represent a stack of constant values.
Provide value semantics, but use efficient reference-counting underneath
to avoid copies. */
template <typename T, typename Stack>
class cmConstStack
{
struct Entry;
std::shared_ptr<Entry const> TopEntry;
public:
/** Default-construct an empty stack. */
cmConstStack();
/** Get a stack with the given call context added to the top. */
Stack Push(T value) const;
/** Get a stack with the top level removed.
May not be called until after a matching Push. */
Stack Pop() const;
/** Get the value at the top of the stack.
This may be called only if Empty() would return false. */
T const& Top() const;
/** Return true if this stack is empty. */
bool Empty() const;
protected:
cmConstStack(std::shared_ptr<Entry const> parent, T value);
cmConstStack(std::shared_ptr<Entry const> top);
};