perf(detect-libc): faster musl check by looking for ldd file

lib/cache.js

@@ -0,0 +1,34 @@
+/**
+ * @type {Record<string, string | undefined | null>}
+ */
+const cacheObject = {};
+
+module.exports = {
+  cacheFn: (key, fn, async = false) => {
+    return () => {
+      const cachedValue = cacheObject[key];
+
+      if (cachedValue !== undefined) {
+        if (async) {
+          return Promise.resolve(cachedValue);
+        }
+
+        return cachedValue;
+      }
+
+      const result = fn();
+
+      if (async) {
+        return result.then(value => {
+          cacheObject[key] = value;
+
+          return value;
+        });
+      }
+
+      cacheObject[key] = result;
+
+      return result;
+    };
+  }
+};

lib/detect-libc.js

@@ -5,6 +5,10 @@
 
 const childProcess = require('child_process');
 const { isLinux, getReport } = require('./process');
+const { LDD_PATH, readFile, readFileSync } = require('./filesystem');
+
+let cachedFamilyFilesystem;
+let cachedVersionFilesystem;
 
 const command = 'getconf GNU_LIBC_VERSION 2>&1 || true; ldd --version 2>&1 || true';
 let commandOut = '';
@@ -39,6 +43,13 @@ const safeCommandSync = () => {
  */
 const GLIBC = 'glibc';
 
+/**
+ * A Regexp constant to get the GLIBC Version.
+ * @type {string}
+ * @public
+ */
+const RE_GLIBC_VERSION = /GLIBC\s(\d+\.\d+)/;
+
 /**
  * A String constant containing the value `musl`.
  * @type {string}
@@ -72,14 +83,49 @@ const familyFromCommand = (out) => {
   return null;
 };
 
+const familyFromFilesystem = async () => {
+  if (cachedFamilyFilesystem !== undefined) {
+    return cachedFamilyFilesystem;
+  }
+  cachedFamilyFilesystem = null;
+  try {
+    const lddContent = await readFile(LDD_PATH);
+    if (lddContent.includes('musl')) {
+      cachedFamilyFilesystem = MUSL;
+    } else if (lddContent.includes('GLIBC')) {
+      cachedFamilyFilesystem = GLIBC;
+    }
+  } catch (e) {}
+  return cachedFamilyFilesystem;
+};
+
+const familyFromFilesystemSync = () => {
+  if (cachedFamilyFilesystem !== undefined) {
+    return cachedFamilyFilesystem;
+  }
+  cachedFamilyFilesystem = null;
+  try {
+    const lddContent = readFileSync(LDD_PATH);
+    if (lddContent.includes('musl')) {
+      cachedFamilyFilesystem = MUSL;
+    } else if (lddContent.includes('GLIBC')) {
+      cachedFamilyFilesystem = GLIBC;
+    }
+  } catch (e) {}
+  return cachedFamilyFilesystem;
+};
+
 /**
  * Resolves with the libc family when it can be determined, `null` otherwise.
  * @returns {Promise<?string>}
  */
 const family = async () => {
   let family = null;
   if (isLinux()) {
-    family = familyFromReport();
+    family = await familyFromFilesystem();
+    if (!family) {
+      family = familyFromReport();
+    }
     if (!family) {
       const out = await safeCommand();
       family = familyFromCommand(out);
@@ -95,7 +141,10 @@ const family = async () => {
 const familySync = () => {
   let family = null;
   if (isLinux()) {
-    family = familyFromReport();
+    family = familyFromFilesystemSync();
+    if (!family) {
+      family = familyFromReport();
+    }
     if (!family) {
       const out = safeCommandSync();
       family = familyFromCommand(out);
@@ -116,6 +165,38 @@ const isNonGlibcLinux = async () => isLinux() && await family() !== GLIBC;
  */
 const isNonGlibcLinuxSync = () => isLinux() && familySync() !== GLIBC;
 
+const versionFromFilesystem = async () => {
+  if (cachedVersionFilesystem !== undefined) {
+    return cachedVersionFilesystem;
+  }
+  cachedVersionFilesystem = null;
+  try {
+    const lddContent = await readFile(LDD_PATH);
+    const versionMatch = lddContent.match(RE_GLIBC_VERSION);
+
+    if (versionMatch) {
+      cachedVersionFilesystem = versionMatch[1];
+    }
+  } catch (e) {}
+  return cachedVersionFilesystem;
+};
+
+const versionFromFilesystemSync = () => {
+  if (cachedVersionFilesystem !== undefined) {
+    return cachedVersionFilesystem;
+  }
+  cachedVersionFilesystem = null;
+  try {
+    const lddContent = readFileSync(LDD_PATH);
+    const versionMatch = lddContent.match(RE_GLIBC_VERSION);
+
+    if (versionMatch) {
+      cachedVersionFilesystem = versionMatch[1];
+    }
+  } catch (e) {}
+  return cachedVersionFilesystem;
+};
+
 const versionFromReport = () => {
   const report = getReport();
   if (report.header && report.header.glibcVersionRuntime) {
@@ -144,7 +225,10 @@ const versionFromCommand = (out) => {
 const version = async () => {
   let version = null;
   if (isLinux()) {
-    version = versionFromReport();
+    version = await versionFromFilesystem();
+    if (!version) {
+      version = versionFromReport();
+    }
     if (!version) {
       const out = await safeCommand();
       version = versionFromCommand(out);
@@ -160,7 +244,10 @@ const version = async () => {
 const versionSync = () => {
   let version = null;
   if (isLinux()) {
-    version = versionFromReport();
+    version = versionFromFilesystemSync();
+    if (!version) {
+      version = versionFromReport();
+    }
     if (!version) {
       const out = safeCommandSync();
       version = versionFromCommand(out);

lib/filesystem.js

@@ -0,0 +1,36 @@
+const fs = require('fs');
+
+/**
+ * The path where we can find the ldd
+ */
+const LDD_PATH = '/usr/bin/ldd';
+
+/**
+ * Read the content of a file synchronous
+ *
+ * @param {string} path
+ * @returns {string}
+ */
+const readFileSync = path => fs.readFileSync(path, 'utf-8');
+
+/**
+ * Read the content of a file
+ *
+ * @param {string} path
+ * @returns {Promise<string>}
+ */
+const readFile = path => new Promise((resolve, reject) => {
+  fs.readFile(path, 'utf-8', (err, data) => {
+    if (err) {
+      reject(err);
+    } else {
+      resolve(data);
+    }
+  });
+});
+
+module.exports = {
+  LDD_PATH,
+  readFileSync,
+  readFile
+};

test/fixtexture-file.txt

@@ -0,0 +1 @@
+1