summaryrefslogtreecommitdiffstats
path: root/js/xpconnect/src/JSServices.cpp
blob: cb8fe6cdcaf4ff9465df2cfe8fb135eecb82253f (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* vim: set ts=8 sts=2 et sw=2 tw=80: */
/* 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/. */

#include "xpcprivate.h"
#include "StaticComponents.h"
#include "mozilla/ErrorResult.h"
#include "mozilla/ProfilerLabels.h"
#include "js/PropertyAndElement.h"  // JS_DefineProperty, JS_DefinePropertyById
#include "js/String.h"              // JS::LinearStringHasLatin1Chars
#include "nsJSUtils.h"

using namespace mozilla;
using namespace JS;

namespace xpc {

static bool Services_NewEnumerate(JSContext* cx, HandleObject obj,
                                  MutableHandleIdVector properties,
                                  bool enumerableOnly);
static bool Services_Resolve(JSContext* cx, HandleObject obj, HandleId id,
                             bool* resolvedp);
static bool Services_MayResolve(const JSAtomState& names, jsid id,
                                JSObject* maybeObj);

static const JSClassOps sServices_ClassOps = {
    nullptr,                // addProperty
    nullptr,                // delProperty
    nullptr,                // enumerate
    Services_NewEnumerate,  // newEnumerate
    Services_Resolve,       // resolve
    Services_MayResolve,    // mayResolve
    nullptr,                // finalize
    nullptr,                // call
    nullptr,                // construct
    nullptr,                // trace
};

static const JSClass sServices_Class = {"JSServices", 0, &sServices_ClassOps};

JSObject* NewJSServices(JSContext* cx) {
  return JS_NewObject(cx, &sServices_Class);
}

static bool Services_NewEnumerate(JSContext* cx, HandleObject obj,
                                  MutableHandleIdVector properties,
                                  bool enumerableOnly) {
  auto services = xpcom::StaticComponents::GetJSServices();

  if (!properties.reserve(services.Length())) {
    JS_ReportOutOfMemory(cx);
    return false;
  }

  RootedId id(cx);
  RootedString name(cx);
  for (const auto& service : services) {
    name = JS_AtomizeString(cx, service.Name().get());
    if (!name || !JS_StringToId(cx, name, &id)) {
      return false;
    }
    properties.infallibleAppend(id);
  }

  return true;
}

static JSLinearString* GetNameIfLatin1(jsid id) {
  if (id.isString()) {
    JSLinearString* name = id.toLinearString();
    if (JS::LinearStringHasLatin1Chars(name)) {
      return name;
    }
  }
  return nullptr;
}

static bool GetServiceImpl(JSContext* cx, const xpcom::JSServiceEntry& service,
                           JS::MutableHandleObject aObj, ErrorResult& aRv) {
  nsresult rv;
  nsCOMPtr<nsISupports> inst = service.Module().GetService(&rv);
  if (!inst) {
    aRv.Throw(rv);
    return false;
  }

  auto ifaces = service.Interfaces();

  if (ifaces.Length() == 0) {
    // If we weren't given any interfaces, we're expecting either a WebIDL
    // object or a wrapped JS object. In the former case, the object will handle
    // its own wrapping, and there's nothing to do. In the latter case, we want
    // to unwrap the underlying JS object.
    if (nsCOMPtr<nsIXPConnectWrappedJS> wrappedJS = do_QueryInterface(inst)) {
      aObj.set(wrappedJS->GetJSObject());
      return !!aObj;
    }
  }

  JS::RootedValue val(cx);

  const nsIID* iid = ifaces.Length() ? ifaces[0] : nullptr;
  xpcObjectHelper helper(inst);
  if (!XPCConvert::NativeInterface2JSObject(cx, &val, helper, iid,
                                            /* allowNativeWrapper */ true,
                                            &rv)) {
    aRv.Throw(rv);
    return false;
  }

  if (ifaces.Length() > 1) {
    auto* wn = XPCWrappedNative::Get(&val.toObject());
    for (const nsIID* iid : Span(ifaces).From(1)) {
      // Ignore any supplemental interfaces that aren't implemented. Tests do
      // weird things with some services, and JS can generally handle the
      // interfaces being absent.
      Unused << wn->FindTearOff(cx, *iid);
    }
  }

  aObj.set(&val.toObject());
  return true;
}

static JSObject* GetService(JSContext* cx, const xpcom::JSServiceEntry& service,
                            ErrorResult& aRv) {
  JS::RootedObject obj(cx);
  if (!GetServiceImpl(cx, service, &obj, aRv)) {
    return nullptr;
  }
  return obj;
}

static bool Services_Resolve(JSContext* cx, HandleObject obj, HandleId id,
                             bool* resolvedp) {
  *resolvedp = false;
  JSLinearString* name = GetNameIfLatin1(id);
  if (!name) {
    return true;
  }

  nsAutoJSLinearCString nameStr(name);
  if (const auto* service = xpcom::JSServiceEntry::Lookup(nameStr)) {
    AUTO_PROFILER_LABEL_DYNAMIC_NSCSTRING_NONSENSITIVE("Services_Resolve",
                                                       OTHER, service->Name());
    *resolvedp = true;

    ErrorResult rv;
    JS::RootedValue val(cx);

    val.setObjectOrNull(GetService(cx, *service, rv));
    if (rv.MaybeSetPendingException(cx)) {
      return false;
    }

    return JS_DefinePropertyById(cx, obj, id, val, JSPROP_ENUMERATE);
  }
  return true;
}

static bool Services_MayResolve(const JSAtomState& names, jsid id,
                                JSObject* maybeObj) {
  if (JSLinearString* name = GetNameIfLatin1(id)) {
    nsAutoJSLinearCString nameStr(name);
    return xpcom::JSServiceEntry::Lookup(nameStr);
  }
  return false;
}

}  // namespace xpc