feat: add a command to download the Hermes Sampling Profiler to a local machine

packages/cli/package.json

@@ -33,6 +33,7 @@
     "@react-native-community/cli-server-api": "^4.10.1",
     "@react-native-community/cli-tools": "^4.10.1",
     "@react-native-community/cli-types": "^4.10.1",
+    "@types/source-map": "^0.5.7",
     "chalk": "^3.0.0",
     "command-exists": "^1.2.8",
     "commander": "^2.19.0",
@@ -59,6 +60,7 @@
     "pretty-format": "^25.2.0",
     "semver": "^6.3.0",
     "serve-static": "^1.13.1",
+    "source-map": "^0.7.3",
     "strip-ansi": "^5.2.0",
     "sudo-prompt": "^9.0.0",
     "wcwidth": "^1.0.1"

packages/cli/src/commands/profile/EventInterfaces.ts

@@ -0,0 +1,136 @@
+import {EventsPhase} from './Phases';
+
+export interface SharedEventProperties {
+  /**
+   * name of the event
+   */
+  name?: string;
+  /**
+   * event category
+   */
+  cat?: string;
+  /**
+   * tracing clock timestamp
+   */
+  ts?: number;
+  /**
+   * process ID
+   */
+  pid?: number;
+  /**
+   * thread ID
+   */
+  tid?: number;
+  /**
+   * event type (phase)
+   */
+  ph: EventsPhase;
+  /**
+   * id for a stackFrame object
+   */
+  sf?: number;
+  /**
+   * thread clock timestamp
+   */
+  tts?: number;
+  /**
+   * a fixed color name
+   */
+  cname?: string;
+  /**
+   * event arguments
+   */
+  args?: {[key in string]: any};
+}
+
+interface DurationEventBegin extends SharedEventProperties {
+  ph: EventsPhase.DURATION_EVENTS_BEGIN;
+}
+
+interface DurationEventEnd extends SharedEventProperties {
+  ph: EventsPhase.DURATION_EVENTS_END;
+}
+
+export type DurationEvent = DurationEventBegin | DurationEventEnd;
+
+export type Event = DurationEvent;
+
+/**
+ * Each item in the stackFrames object of the hermes profile
+ */
+export interface HermesStackFrame {
+  line: string;
+  column: string;
+  funcLine: string;
+  funcColumn: string;
+  name: string;
+  category: string;
+  /**
+   * A parent function may or may not exist
+   */
+  parent?: number;
+}
+/**
+ * Each item in the samples array of the hermes profile
+ */
+export interface HermesSample {
+  cpu: string;
+  name: string;
+  ts: string;
+  pid: number;
+  tid: string;
+  weight: string;
+  /**
+   * Will refer to an element in the stackFrames object of the Hermes Profile
+   */
+  sf: number;
+  stackFrameData?: HermesStackFrame;
+}
+
+/**
+ * Hermes Profile Interface
+ */
+export interface HermesCPUProfile {
+  traceEvents: SharedEventProperties[];
+  samples: HermesSample[];
+  stackFrames: {[key in string]: HermesStackFrame};
+}
+
+export interface CPUProfileChunk {
+  id: string;
+  pid: number;
+  tid: string;
+  startTime: number;
+  nodes: CPUProfileChunkNode[];
+  samples: number[];
+  timeDeltas: number[];
+}
+
+export interface CPUProfileChunkNode {
+  id: number;
+  callFrame: {
+    line: string;
+    column: string;
+    funcLine: string;
+    funcColumn: string;
+    name: string;
+    url?: string;
+    category: string;
+  };
+  parent?: number;
+}
+
+export type CPUProfileChunker = {
+  nodes: CPUProfileChunkNode[];
+  sampleNumbers: number[];
+  timeDeltas: number[];
+};
+
+export interface SourceMap {
+  version: string;
+  sources: string[];
+  sourceContent: string[];
+  x_facebook_sources: {names: string[]; mappings: string}[] | null;
+  names: string[];
+  mappings: string;
+}

packages/cli/src/commands/profile/Phases.ts

@@ -0,0 +1,30 @@
+export enum EventsPhase {
+  DURATION_EVENTS_BEGIN = 'B',
+  DURATION_EVENTS_END = 'E',
+  COMPLETE_EVENTS = 'X',
+  INSTANT_EVENTS = 'I',
+  COUNTER_EVENTS = 'C',
+  ASYNC_EVENTS_NESTABLE_START = 'b',
+  ASYNC_EVENTS_NESTABLE_INSTANT = 'n',
+  ASYNC_EVENTS_NESTABLE_END = 'e',
+  FLOW_EVENTS_START = 's',
+  FLOW_EVENTS_STEP = 't',
+  FLOW_EVENTS_END = 'f',
+  SAMPLE_EVENTS = 'P',
+  OBJECT_EVENTS_CREATED = 'N',
+  OBJECT_EVENTS_SNAPSHOT = 'O',
+  OBJECT_EVENTS_DESTROYED = 'D',
+  METADATA_EVENTS = 'M',
+  MEMORY_DUMP_EVENTS_GLOBAL = 'V',
+  MEMORY_DUMP_EVENTS_PROCESS = 'v',
+  MARK_EVENTS = 'R',
+  CLOCK_SYNC_EVENTS = 'c',
+  CONTEXT_EVENTS_ENTER = '(',
+  CONTEXT_EVENTS_LEAVE = ')',
+  // Deprecated
+  ASYNC_EVENTS_START = 'S',
+  ASYNC_EVENTS_STEP_INTO = 'T',
+  ASYNC_EVENTS_STEP_PAST = 'p',
+  ASYNC_EVENTS_END = 'F',
+  LINKED_ID_EVENTS = '=',
+}