summaryrefslogtreecommitdiffstats
path: root/js/src/builtin/Generator.js
blob: ada80e3006bb40e8b7c496a744da38e59fa6cf02 (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
/* 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/. */

function GeneratorNext(val) {
  // The IsSuspendedGenerator call below is not necessary for correctness.
  // It's a performance optimization to check for the common case with a
  // single call. It's also inlined in Baseline.

  if (!IsSuspendedGenerator(this)) {
    if (!IsObject(this) || !IsGeneratorObject(this)) {
      return callFunction(
        CallGeneratorMethodIfWrapped,
        this,
        val,
        "GeneratorNext"
      );
    }

    if (GeneratorObjectIsClosed(this)) {
      return { value: undefined, done: true };
    }

    if (GeneratorIsRunning(this)) {
      ThrowTypeError(JSMSG_NESTING_GENERATOR);
    }
  }

  try {
    return resumeGenerator(this, val, "next");
  } catch (e) {
    if (!GeneratorObjectIsClosed(this)) {
      GeneratorSetClosed(this);
    }
    throw e;
  }
}

function GeneratorThrow(val) {
  if (!IsSuspendedGenerator(this)) {
    if (!IsObject(this) || !IsGeneratorObject(this)) {
      return callFunction(
        CallGeneratorMethodIfWrapped,
        this,
        val,
        "GeneratorThrow"
      );
    }

    if (GeneratorObjectIsClosed(this)) {
      throw val;
    }

    if (GeneratorIsRunning(this)) {
      ThrowTypeError(JSMSG_NESTING_GENERATOR);
    }
  }

  try {
    return resumeGenerator(this, val, "throw");
  } catch (e) {
    if (!GeneratorObjectIsClosed(this)) {
      GeneratorSetClosed(this);
    }
    throw e;
  }
}

function GeneratorReturn(val) {
  if (!IsSuspendedGenerator(this)) {
    if (!IsObject(this) || !IsGeneratorObject(this)) {
      return callFunction(
        CallGeneratorMethodIfWrapped,
        this,
        val,
        "GeneratorReturn"
      );
    }

    if (GeneratorObjectIsClosed(this)) {
      return { value: val, done: true };
    }

    if (GeneratorIsRunning(this)) {
      ThrowTypeError(JSMSG_NESTING_GENERATOR);
    }
  }

  try {
    var rval = { value: val, done: true };
    return resumeGenerator(this, rval, "return");
  } catch (e) {
    if (!GeneratorObjectIsClosed(this)) {
      GeneratorSetClosed(this);
    }
    throw e;
  }
}

function InterpretGeneratorResume(gen, val, kind) {
  // If we want to resume a generator in the interpreter, the script containing
  // the resumeGenerator/JSOp::Resume also has to run in the interpreter. The
  // forceInterpreter() call below compiles to a bytecode op that prevents us
  // from JITing this script.
  forceInterpreter();
  if (kind === "next") {
    return resumeGenerator(gen, val, "next");
  }
  if (kind === "throw") {
    return resumeGenerator(gen, val, "throw");
  }
  assert(kind === "return", "Invalid resume kind");
  return resumeGenerator(gen, val, "return");
}