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1 : /* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
2 : /* This Source Code Form is subject to the terms of the Mozilla Public
3 : * License, v. 2.0. If a copy of the MPL was not distributed with this
4 : * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
5 :
6 : /* Public declarations for xptcall. */
7 :
8 : #ifndef xptcall_h___
9 : #define xptcall_h___
10 :
11 : #include "nscore.h"
12 : #include "nsISupports.h"
13 : #include "xpt_struct.h"
14 : #include "xptinfo.h"
15 : #include "js/Value.h"
16 : #include "mozilla/MemoryReporting.h"
17 :
18 39670 : struct nsXPTCMiniVariant
19 : {
20 : // No ctors or dtors so that we can use arrays of these on the stack
21 : // with no penalty.
22 : union
23 39670 : {
24 : int8_t i8;
25 : int16_t i16;
26 : int32_t i32;
27 : int64_t i64;
28 : uint8_t u8;
29 : uint16_t u16;
30 : uint32_t u32;
31 : uint64_t u64;
32 : float f;
33 : double d;
34 : bool b;
35 : char c;
36 : char16_t wc;
37 : void* p;
38 :
39 : // Types below here are unknown to the assembly implementations, and
40 : // therefore _must_ be passed with indirect semantics. We put them in
41 : // the union here for type safety, so that we can avoid void* tricks.
42 : JS::Value j;
43 : } val;
44 : };
45 :
46 28433 : struct nsXPTCVariant : public nsXPTCMiniVariant
47 : {
48 : // No ctors or dtors so that we can use arrays of these on the stack
49 : // with no penalty.
50 :
51 : // inherits 'val' here
52 : void* ptr;
53 : nsXPTType type;
54 : uint8_t flags;
55 :
56 : enum
57 : {
58 : //
59 : // Bitflag definitions
60 : //
61 :
62 : // Indicates that ptr (above, and distinct from val.p) is the value that
63 : // should be passed on the stack.
64 : //
65 : // In theory, ptr could point anywhere. But in practice it always points
66 : // to &val. So this flag is used to pass 'val' by reference, letting us
67 : // avoid the extra allocation we would incur if we were to use val.p.
68 : //
69 : // Various parts of XPConnect assume that ptr==&val, so we enforce it
70 : // explicitly with SetIndirect() and IsIndirect().
71 : //
72 : // Since ptr always points to &val, the semantics of this flag are kind of
73 : // dumb, since the ptr field is unnecessary. But changing them would
74 : // require changing dozens of assembly files, so they're likely to stay
75 : // the way they are.
76 : PTR_IS_DATA = 0x1,
77 :
78 : // Indicates that the value we hold requires some sort of cleanup (memory
79 : // deallocation, interface release, JS::Value unrooting, etc). The precise
80 : // cleanup that is performed depends on the 'type' field above.
81 : // If the value is an array, this flag specifies whether the elements
82 : // within the array require cleanup (we always clean up the array itself,
83 : // so this flag would be redundant for that purpose).
84 : VAL_NEEDS_CLEANUP = 0x2
85 : };
86 :
87 28433 : void ClearFlags() {flags = 0;}
88 11589 : void SetIndirect() {ptr = &val; flags |= PTR_IS_DATA;}
89 20467 : void SetValNeedsCleanup() {flags |= VAL_NEEDS_CLEANUP;}
90 :
91 : bool IsIndirect() const {return 0 != (flags & PTR_IS_DATA);}
92 25027 : bool DoesValNeedCleanup() const {return 0 != (flags & VAL_NEEDS_CLEANUP);}
93 :
94 : // Internal use only. Use IsIndirect() instead.
95 85344 : bool IsPtrData() const {return 0 != (flags & PTR_IS_DATA);}
96 :
97 : void Init(const nsXPTCMiniVariant& mv, const nsXPTType& t, uint8_t f)
98 : {
99 : type = t;
100 : flags = f;
101 :
102 : if(f & PTR_IS_DATA)
103 : {
104 : ptr = mv.val.p;
105 : val.p = nullptr;
106 : }
107 : else
108 : {
109 : ptr = nullptr;
110 : val.p = nullptr; // make sure 'val.p' is always initialized
111 : switch(t.TagPart()) {
112 : case nsXPTType::T_I8: val.i8 = mv.val.i8; break;
113 : case nsXPTType::T_I16: val.i16 = mv.val.i16; break;
114 : case nsXPTType::T_I32: val.i32 = mv.val.i32; break;
115 : case nsXPTType::T_I64: val.i64 = mv.val.i64; break;
116 : case nsXPTType::T_U8: val.u8 = mv.val.u8; break;
117 : case nsXPTType::T_U16: val.u16 = mv.val.u16; break;
118 : case nsXPTType::T_U32: val.u32 = mv.val.u32; break;
119 : case nsXPTType::T_U64: val.u64 = mv.val.u64; break;
120 : case nsXPTType::T_FLOAT: val.f = mv.val.f; break;
121 : case nsXPTType::T_DOUBLE: val.d = mv.val.d; break;
122 : case nsXPTType::T_BOOL: val.b = mv.val.b; break;
123 : case nsXPTType::T_CHAR: val.c = mv.val.c; break;
124 : case nsXPTType::T_WCHAR: val.wc = mv.val.wc; break;
125 : case nsXPTType::T_VOID: /* fall through */
126 : case nsXPTType::T_IID: /* fall through */
127 : case nsXPTType::T_DOMSTRING: /* fall through */
128 : case nsXPTType::T_CHAR_STR: /* fall through */
129 : case nsXPTType::T_WCHAR_STR: /* fall through */
130 : case nsXPTType::T_INTERFACE: /* fall through */
131 : case nsXPTType::T_INTERFACE_IS: /* fall through */
132 : case nsXPTType::T_ARRAY: /* fall through */
133 : case nsXPTType::T_PSTRING_SIZE_IS: /* fall through */
134 : case nsXPTType::T_PWSTRING_SIZE_IS: /* fall through */
135 : case nsXPTType::T_UTF8STRING: /* fall through */
136 : case nsXPTType::T_CSTRING: /* fall through */
137 : default: val.p = mv.val.p; break;
138 : }
139 : }
140 : }
141 : };
142 :
143 939 : class nsIXPTCProxy : public nsISupports
144 : {
145 : public:
146 : NS_IMETHOD CallMethod(uint16_t aMethodIndex,
147 : const XPTMethodDescriptor *aInfo,
148 : nsXPTCMiniVariant *aParams) = 0;
149 : };
150 :
151 : /**
152 : * This is a typedef to avoid confusion between the canonical
153 : * nsISupports* that provides object identity and an interface pointer
154 : * for inheriting interfaces that aren't known at compile-time.
155 : */
156 : typedef nsISupports nsISomeInterface;
157 :
158 : /**
159 : * Get a proxy object to implement the specified interface.
160 : *
161 : * @param aIID The IID of the interface to implement.
162 : * @param aOuter An object to receive method calls from the proxy object.
163 : * The stub forwards QueryInterface/AddRef/Release to the
164 : * outer object. The proxy object does not hold a reference to
165 : * the outer object; it is the caller's responsibility to
166 : * ensure that this pointer remains valid until the stub has
167 : * been destroyed.
168 : * @param aStub Out parameter for the new proxy object. The object is
169 : * not addrefed. The object never destroys itself. It must be
170 : * explicitly destroyed by calling
171 : * NS_DestroyXPTCallStub when it is no longer needed.
172 : */
173 : XPCOM_API(nsresult)
174 : NS_GetXPTCallStub(REFNSIID aIID, nsIXPTCProxy* aOuter,
175 : nsISomeInterface* *aStub);
176 :
177 : /**
178 : * Destroys an XPTCall stub previously created with NS_GetXPTCallStub.
179 : */
180 : XPCOM_API(void)
181 : NS_DestroyXPTCallStub(nsISomeInterface* aStub);
182 :
183 : /**
184 : * Measures the size of an XPTCall stub previously created with NS_GetXPTCallStub.
185 : */
186 : XPCOM_API(size_t)
187 : NS_SizeOfIncludingThisXPTCallStub(const nsISomeInterface* aStub, mozilla::MallocSizeOf aMallocSizeOf);
188 :
189 : // this is extern "C" because on some platforms it is implemented in assembly
190 : extern "C" nsresult
191 : NS_InvokeByIndex(nsISupports* that, uint32_t methodIndex,
192 : uint32_t paramCount, nsXPTCVariant* params);
193 :
194 : #endif /* xptcall_h___ */
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