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Diffstat (limited to 'xpcom/reflect/xptcall/xptcall.h')
| -rw-r--r-- | xpcom/reflect/xptcall/xptcall.h | 173 |
1 files changed, 173 insertions, 0 deletions
diff --git a/xpcom/reflect/xptcall/xptcall.h b/xpcom/reflect/xptcall/xptcall.h new file mode 100644 index 0000000000..a36ca53d23 --- /dev/null +++ b/xpcom/reflect/xptcall/xptcall.h @@ -0,0 +1,173 @@ +/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */ +/* This Source Code Form is subject to the terms of the Mozilla Public + * License, v. 2.0. If a copy of the MPL was not distributed with this + * file, You can obtain one at http://mozilla.org/MPL/2.0/. */ + +/* Public declarations for xptcall. */ + +#ifndef xptcall_h___ +#define xptcall_h___ + +#include "nscore.h" +#include "nsISupports.h" +#include "xptinfo.h" +#include "js/Value.h" +#include "mozilla/MemoryReporting.h" + +struct nsXPTCMiniVariant { + // No ctors or dtors so that we can use arrays of these on the stack + // with no penalty. + union Union { + int8_t i8; + int16_t i16; + int32_t i32; + int64_t i64; + uint8_t u8; + uint16_t u16; + uint32_t u32; + uint64_t u64; + float f; + double d; + bool b; + char c; + char16_t wc; + void* p; + }; + + Union val; +}; + +static_assert(offsetof(nsXPTCMiniVariant, val) == 0, + "nsXPTCMiniVariant must be a thin wrapper"); + +struct nsXPTCVariant { + union ExtendedVal { + // ExtendedVal is an extension on nsXPTCMiniVariant. It contains types + // unknown to the assembly implementations which must be passed by indirect + // semantics. + // + // nsXPTCVariant contains enough space to store ExtendedVal inline, which + // can be used to store these types when IsIndirect() is true. + nsXPTCMiniVariant mini; + + nsID nsid; + nsCString nscstr; + nsString nsstr; + JS::Value jsval; + xpt::detail::UntypedTArray array; + + // This type contains non-standard-layout types, so needs an explicit + // Ctor/Dtor - we'll just delete them. + ExtendedVal() = delete; + ~ExtendedVal() = delete; + }; + + union { + // The `val` field from nsXPTCMiniVariant. + nsXPTCMiniVariant::Union val; + + // Storage for any extended variants. + ExtendedVal ext; + }; + + nsXPTType type; + uint8_t flags; + + // Clear to a valid, null state. + nsXPTCVariant() { + memset(this, 0, sizeof(nsXPTCVariant)); + type = nsXPTType::T_VOID; + } + + enum { + // + // Bitflag definitions + // + + // Indicates that we &val.p should be passed n the stack, i.e. that + // val should be passed by reference. + IS_INDIRECT = 0x1, + }; + + void ClearFlags() { flags = 0; } + void SetIndirect() { flags |= IS_INDIRECT; } + + bool IsIndirect() const { return 0 != (flags & IS_INDIRECT); } + + // Implicitly convert to nsXPTCMiniVariant. + operator nsXPTCMiniVariant&() { return *(nsXPTCMiniVariant*)&val; } + operator const nsXPTCMiniVariant&() const { + return *(const nsXPTCMiniVariant*)&val; + } + + // As this type contains an anonymous union, we need to provide an explicit + // destructor. + ~nsXPTCVariant() {} +}; + +static_assert(offsetof(nsXPTCVariant, val) == offsetof(nsXPTCVariant, ext), + "nsXPTCVariant::{ext,val} must have matching offsets"); + +// static_assert that nsXPTCVariant::ExtendedVal is large enough and +// well-aligned enough for every XPT-supported type. +#define XPT_CHECK_SIZEOF(xpt, type) \ + static_assert(sizeof(nsXPTCVariant::ExtendedVal) >= sizeof(type), \ + "nsXPTCVariant::ext not big enough for " #xpt " (" #type ")"); \ + static_assert(MOZ_ALIGNOF(nsXPTCVariant::ExtendedVal) >= MOZ_ALIGNOF(type), \ + "nsXPTCVariant::ext not aligned enough for " #xpt " (" #type \ + ")"); +XPT_FOR_EACH_TYPE(XPT_CHECK_SIZEOF) +#undef XPT_CHECK_SIZEOF + +class nsIXPTCProxy : public nsISupports { + public: + NS_IMETHOD CallMethod(uint16_t aMethodIndex, const nsXPTMethodInfo* aInfo, + nsXPTCMiniVariant* aParams) = 0; +}; + +/** + * This is a typedef to avoid confusion between the canonical + * nsISupports* that provides object identity and an interface pointer + * for inheriting interfaces that aren't known at compile-time. + */ +typedef nsISupports nsISomeInterface; + +/** + * Get a proxy object to implement the specified interface. + * + * @param aIID The IID of the interface to implement. + * @param aOuter An object to receive method calls from the proxy object. + * The stub forwards QueryInterface/AddRef/Release to the + * outer object. The proxy object does not hold a reference to + * the outer object; it is the caller's responsibility to + * ensure that this pointer remains valid until the stub has + * been destroyed. + * @param aStub Out parameter for the new proxy object. The object is + * not addrefed. The object never destroys itself. It must be + * explicitly destroyed by calling + * NS_DestroyXPTCallStub when it is no longer needed. + */ +XPCOM_API(nsresult) +NS_GetXPTCallStub(REFNSIID aIID, nsIXPTCProxy* aOuter, + nsISomeInterface** aStub); + +/** + * Destroys an XPTCall stub previously created with NS_GetXPTCallStub. + */ +XPCOM_API(void) +NS_DestroyXPTCallStub(nsISomeInterface* aStub); + +/** + * Measures the size of an XPTCall stub previously created with + * NS_GetXPTCallStub. + */ +XPCOM_API(size_t) +NS_SizeOfIncludingThisXPTCallStub(const nsISomeInterface* aStub, + mozilla::MallocSizeOf aMallocSizeOf); + +// this is extern "C" because on some platforms it is implemented in assembly +extern "C" nsresult NS_InvokeByIndex(nsISupports* that, uint32_t methodIndex, + uint32_t paramCount, + nsXPTCVariant* params); + +#endif /* xptcall_h___ */ |