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
|
'use strict';
process.emitWarning(
'These APIs are for internal testing only. Do not use them.',
'internal/test/heap');
const { createHeapDump, buildEmbedderGraph } = internalBinding('heap_utils');
const assert = require('assert');
// This is not suitable for production code. It creates a full V8 heap dump,
// parses it as JSON, and then creates complex objects from it, leading
// to significantly increased memory usage.
function createJSHeapDump() {
const dump = createHeapDump();
const meta = dump.snapshot.meta;
const nodes =
readHeapInfo(dump.nodes, meta.node_fields, meta.node_types, dump.strings);
const edges =
readHeapInfo(dump.edges, meta.edge_fields, meta.edge_types, dump.strings);
for (const node of nodes) {
node.incomingEdges = [];
node.outgoingEdges = [];
}
let fromNodeIndex = 0;
let edgeIndex = 0;
for (const { type, name_or_index, to_node } of edges) {
while (edgeIndex === nodes[fromNodeIndex].edge_count) {
edgeIndex = 0;
fromNodeIndex++;
}
const toNode = nodes[to_node / meta.node_fields.length];
const fromNode = nodes[fromNodeIndex];
const edge = {
type,
to: toNode,
from: fromNode,
name: typeof name_or_index === 'string' ? name_or_index : null
};
toNode.incomingEdges.push(edge);
fromNode.outgoingEdges.push(edge);
edgeIndex++;
}
for (const node of nodes)
assert.strictEqual(node.edge_count, node.outgoingEdges.length);
return nodes;
}
function readHeapInfo(raw, fields, types, strings) {
const items = [];
for (var i = 0; i < raw.length; i += fields.length) {
const item = {};
for (var j = 0; j < fields.length; j++) {
const name = fields[j];
let type = types[j];
if (Array.isArray(type)) {
item[name] = type[raw[i + j]];
} else if (name === 'name_or_index') { // type === 'string_or_number'
if (item.type === 'element' || item.type === 'hidden')
type = 'number';
else
type = 'string';
}
if (type === 'string') {
item[name] = strings[raw[i + j]];
} else if (type === 'number' || type === 'node') {
item[name] = raw[i + j];
}
}
items.push(item);
}
return items;
}
module.exports = {
createJSHeapDump,
buildEmbedderGraph
};
|
