Files
react-native/React/CoreModules
Ramanpreet Nara 39d67737c0 Run getConstants method statements on main queue
Summary:
If a NativeModule requires main queue setup, its `getConstants()` method must be executed on the main thead. The legacy NativeModule infra takes care of this for us. With TurboModules, however, all synchronous methods, including `getConstants()`, execute on the JS thread. Therefore, if a TurboModule requires main queue setup, and exports constants, we must execute its `getConstants()` method body on the main queue explicitly.

**Notes:**
- The changes in this diff should be a noop when TurboModules is off, because `RCTUnsafeExecuteOnMainQueueSync` synchronously execute its block on the current thread if the current thread is the main thread.
- If a NativeModule doens't have the `requiresMainQueueSetup` method, but has the `constantsToExport` method, both NativeModules and TurboModules assume that it requires main queue setup.

## Script
```
const exec = require("../lib/exec");
const abspath = require("../lib/abspath");
const relpath = require("../lib/relpath");
const readFile = (filename) => require("fs").readFileSync(filename, "utf8");
const writeFile = (filename, content) =>
  require("fs").writeFileSync(filename, content);

function main() {
  const tmFiles = exec("cd ~/fbsource && xbgs -n 10000 -l constantsToExport")
    .split("\n")
    .filter(Boolean);

  const filesWithoutConstantsToExport = [];
  const filesWithConstantsToExportButNotGetConstants = [];
  const filesExplicitlyNotRequiringMainQueueSetup = [];

  tmFiles
    .filter((filename) => {
      if (filename.includes("microsoft-fork-of-react-native")) {
        return false;
      }

      return /\.mm?$/.test(filename);
    })
    .map(abspath)
    .forEach((filename) => {
      const code = readFile(filename);
      const relFilename = relpath(filename);

      if (!/constantsToExport\s*{/.test(code)) {
        filesWithoutConstantsToExport.push(relFilename);
        return;
      }

      if (!/getConstants\s*{/.test(code)) {
        filesWithConstantsToExportButNotGetConstants.push(relFilename);
        return;
      }

      if (/requiresMainQueueSetup\s*{/.test(code)) {
        const requiresMainQueueSetupRegex = /requiresMainQueueSetup\s*{\s*return\s+(?<requiresMainQueueSetup>YES|NO)/;
        const requiresMainQueueSetupRegexMatch = requiresMainQueueSetupRegex.exec(
          code
        );

        if (!requiresMainQueueSetupRegexMatch) {
          throw new Error(
            "Detected requiresMainQueueSetup method in file " +
              relFilename +
              " but was unable to parse the method return value"
          );
        }

        const {
          requiresMainQueueSetup,
        } = requiresMainQueueSetupRegexMatch.groups;

        if (requiresMainQueueSetup == "NO") {
          filesExplicitlyNotRequiringMainQueueSetup.push(relFilename);
          return;
        }
      }

      const getConstantsTypeRegex = () => /-\s*\((?<type>.*)\)getConstants\s*{/;
      const getConstantsTypeRegexMatch = getConstantsTypeRegex().exec(code);

      if (!getConstantsTypeRegexMatch) {
        throw new Error(
          `Failed to parse return type of getConstants method in file ${relFilename}`
        );
      }

      const getConstantsType = getConstantsTypeRegexMatch.groups.type;

      const getConstantsBody = code
        .split(getConstantsTypeRegex())[2]
        .split("\n}")[0];

      const newGetConstantsBody = `
  __block ${getConstantsType} constants;
  RCTUnsafeExecuteOnMainQueueSync(^{${getConstantsBody
    .replace(/\n/g, "\n  ")
    .replace(/_bridge/g, "self->_bridge")
    .replace(/return /g, "constants = ")}
  });

  return constants;
`;

      writeFile(
        filename,
        code
          .replace(getConstantsBody, newGetConstantsBody)
          .replace("#import", "#import <React/RCTUtils.h>\n#import")
      );
    });

  console.log("Files without constantsToExport: ");
  filesWithoutConstantsToExport.forEach((file) => console.log(file));
  console.log();

  console.log("Files with constantsToExport but no getConstants: ");
  filesWithConstantsToExportButNotGetConstants.forEach((file) =>
    console.log(file)
  );
  console.log();

  console.log("Files with requiresMainQueueSetup = NO: ");
  filesExplicitlyNotRequiringMainQueueSetup.forEach((file) =>
    console.log(file)
  );
}

if (!module.parent) {
  main();
}

```

Changelog: [Internal]

Reviewed By: fkgozali

Differential Revision: D21797048

fbshipit-source-id: a822a858fecdbe976e6197f8339e509dc7cd917f
2020-06-02 23:01:35 -07:00
..
2020-05-15 21:55:52 -07:00
2019-10-16 10:06:34 -07:00
2019-10-16 10:06:34 -07:00
2020-05-12 22:40:29 -07:00
2020-05-12 22:40:29 -07:00
2019-10-16 10:06:34 -07:00
2019-10-16 10:06:34 -07:00
2020-04-07 19:07:19 -07:00