summaryrefslogtreecommitdiffstats
path: root/js/xpconnect/src/XPCThrower.cpp
blob: 2e53cbda81161c9853e371655cf17fa4758b0880 (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
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
/* -*- 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/. */

/* Code for throwing errors into JavaScript. */

#include "xpcprivate.h"
#include "XPCWrapper.h"
#include "js/CharacterEncoding.h"
#include "js/Printf.h"
#include "mozilla/dom/BindingUtils.h"
#include "mozilla/dom/DOMException.h"
#include "mozilla/dom/Exceptions.h"
#include "nsString.h"

using namespace mozilla;
using namespace mozilla::dom;

bool XPCThrower::sVerbose = true;

// static
void XPCThrower::Throw(nsresult rv, JSContext* cx) {
  const char* format;
  if (JS_IsExceptionPending(cx)) {
    return;
  }
  if (!nsXPCException::NameAndFormatForNSResult(rv, nullptr, &format)) {
    format = "";
  }
  dom::Throw(cx, rv, nsDependentCString(format));
}

namespace xpc {

bool Throw(JSContext* cx, nsresult rv) {
  XPCThrower::Throw(rv, cx);
  return false;
}

}  // namespace xpc

/*
 * If there has already been an exception thrown, see if we're throwing the
 * same sort of exception, and if we are, don't clobber the old one. ccx
 * should be the current call context.
 */
// static
bool XPCThrower::CheckForPendingException(nsresult result, JSContext* cx) {
  RefPtr<Exception> e = XPCJSContext::Get()->GetPendingException();
  if (!e) {
    return false;
  }
  XPCJSContext::Get()->SetPendingException(nullptr);

  if (e->GetResult() != result) {
    return false;
  }

  ThrowExceptionObject(cx, e);
  return true;
}

// static
void XPCThrower::Throw(nsresult rv, XPCCallContext& ccx) {
  char* sz;
  const char* format;

  if (CheckForPendingException(rv, ccx)) {
    return;
  }

  if (!nsXPCException::NameAndFormatForNSResult(rv, nullptr, &format)) {
    format = "";
  }

  sz = (char*)format;
  NS_ENSURE_TRUE_VOID(sz);

  if (sz && sVerbose) {
    Verbosify(ccx, &sz, false);
  }

  dom::Throw(ccx, rv, nsDependentCString(sz));

  if (sz && sz != format) {
    js_free(sz);
  }
}

// static
void XPCThrower::ThrowBadResult(nsresult rv, nsresult result,
                                XPCCallContext& ccx) {
  char* sz;
  const char* format;
  const char* name;

  /*
   *  If there is a pending exception when the native call returns and
   *  it has the same error result as returned by the native call, then
   *  the native call may be passing through an error from a previous JS
   *  call. So we'll just throw that exception into our JS.  Note that
   *  we don't need to worry about NS_ERROR_UNCATCHABLE_EXCEPTION,
   *  because presumably there would be no pending exception for that
   *  nsresult!
   */

  if (CheckForPendingException(result, ccx)) {
    return;
  }

  // else...

  if (!nsXPCException::NameAndFormatForNSResult(rv, nullptr, &format) ||
      !format) {
    format = "";
  }

  if (nsXPCException::NameAndFormatForNSResult(result, &name, nullptr) &&
      name) {
    sz = JS_smprintf("%s 0x%x (%s)", format, (unsigned)result, name).release();
  } else {
    sz = JS_smprintf("%s 0x%x", format, (unsigned)result).release();
  }
  NS_ENSURE_TRUE_VOID(sz);

  if (sz && sVerbose) {
    Verbosify(ccx, &sz, true);
  }

  dom::Throw(ccx, result, nsDependentCString(sz));

  if (sz) {
    js_free(sz);
  }
}

// static
void XPCThrower::ThrowBadParam(nsresult rv, unsigned paramNum,
                               XPCCallContext& ccx) {
  char* sz;
  const char* format;

  if (!nsXPCException::NameAndFormatForNSResult(rv, nullptr, &format)) {
    format = "";
  }

  sz = JS_smprintf("%s arg %d", format, paramNum).release();
  NS_ENSURE_TRUE_VOID(sz);

  if (sz && sVerbose) {
    Verbosify(ccx, &sz, true);
  }

  dom::Throw(ccx, rv, nsDependentCString(sz));

  if (sz) {
    js_free(sz);
  }
}

// static
void XPCThrower::Verbosify(XPCCallContext& ccx, char** psz, bool own) {
  char* sz = nullptr;

  if (ccx.HasInterfaceAndMember()) {
    XPCNativeInterface* iface = ccx.GetInterface();
    jsid id = ccx.GetMember()->GetName();
    const char* name;
    JS::UniqueChars bytes;
    if (!JSID_IS_VOID(id)) {
      bytes = JS_EncodeStringToLatin1(ccx, JSID_TO_STRING(id));
      name = bytes ? bytes.get() : "";
    } else {
      name = "Unknown";
    }
    sz =
        JS_smprintf("%s [%s.%s]", *psz, iface->GetNameString(), name).release();
  }

  if (sz) {
    if (own) {
      js_free(*psz);
    }
    *psz = sz;
  }
}