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Reduce duplication in JSI GUI objects implementation.

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- Store the functions in an unordered_map. A no-container implementation
is doable but likely not worth the added code complexity, maybe with
C++20
- Move more things into the _impl.h
- Clear out the un-necessary friends declaration in the specific types
by moving the functions to the public interface, which makes sense.
- Fix a memory leak (JS::PersistentRootedObject weren't deleted).

This doesn't change what one needs to do to add a new type, but it does
reduce the actual code that's necessary, and makes it less error prone.

Differential Revision: https://code.wildfiregames.com/D3214
This was SVN commit r24384.
This commit is contained in:
wraitii
2020-12-13 15:06:18 +00:00
parent 876f6d5e50
commit 1b67a079fb
15 changed files with 202 additions and 277 deletions
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source/gui/Scripting/JSInterface_GUIProxy.h
+42 -4
View File
@@ -23,6 +23,7 @@
#include <utility>
class ScriptInterface;
class ScriptRequest;
// See JSI_GuiProxy below
#if GCC_VERSION
@@ -33,6 +34,22 @@ class ScriptInterface;
# pragma warning(disable: 4265)
#endif
/**
* Proxies need to store some data whose lifetime is tied to an interface.
* This is the virtual interface of that data.
*/
class GUIProxyProps
{
public:
virtual ~GUIProxyProps() {};
// @return true if @param name exists in this cache.
virtual bool has(const std::string& name) const = 0;
// @return the JSFunction matching @param name. Must call has() first as it can assume existence.
virtual JSObject* get(const std::string& name) const = 0;
virtual bool setFunction(const ScriptRequest& rq, const std::string& name, JSNative function, int nargs) = 0;
};
/**
* Handles the js interface with C++ GUI objects.
* Proxy handlers must live for at least as long as the JS runtime
@@ -43,6 +60,17 @@ class ScriptInterface;
* GUI Objects only exist in C++ and have no JS-only properties.
* As such, there is no "target" JS object that this proxy could point to,
* and thus we should inherit from BaseProxyHandler and not js::Wrapper.
*
* Proxies can be used with prototypes and almost treated like regular JS objects.
* However, the default implementation embarks a lot of code that we don't really need here,
* since the only fanciness is that we cache JSFunction* properties.
* As such, these GUI proxies don't have one and instead override get/set directly.
*
* To add a new JSI_GUIProxy, you'll need to:
* - overload the GUI Object's CreateJSObject with the correct types and pointers
* - change the CGUI::AddObjectTypes method
* - explicitly instantiate the template.
*
*/
template<typename GUIObjectType>
class JSI_GUIProxy : public js::BaseProxyHandler
@@ -54,17 +82,27 @@ public:
// For convenience, this is the single instantiated JSI_GUIProxy.
static JSI_GUIProxy& Singleton();
static std::pair<const js::BaseProxyHandler*, void*> CreateData(ScriptInterface& scriptInterface);
// Call this in CGUI::AddObjectTypes.
static std::pair<const js::BaseProxyHandler*, GUIProxyProps*> CreateData(ScriptInterface& scriptInterface);
static void CreateJSObject(const ScriptRequest& rq, GUIObjectType* ptr, GUIProxyProps* data, JS::PersistentRootedObject& val);
protected:
// @param family can't be nullptr because that's used for some DOM object and it crashes.
JSI_GUIProxy() : BaseProxyHandler(this, false, false) {};
// Note: SM provides no virtual destructor for baseProxyHandler.
// This also enforces making proxy handlers dataless static variables.
~JSI_GUIProxy() {};
// This handles returning function properties.
// Specialize this.
bool FuncGetter(JS::HandleObject proxy, const std::string& propName, JS::MutableHandleValue vp) const;
// The default implementations need to know the type of the GUIProxyProps for this proxy type.
// This is done by specializing this struct's alias type.
struct PropCache;
// Specialize this to define the custom properties of this type.
static void CreateFunctions(const ScriptRequest& rq, GUIProxyProps* cache);
// This handles returning custom properties. Specialize this if needed.
bool PropGetter(JS::HandleObject proxy, const std::string& propName, JS::MutableHandleValue vp) const;
protected:
// BaseProxyHandler interface below