tools: add eslint rule for hasCrypto checking

The motivation for this commit is to pick up early on missing checks for
crypto support (when Node is built --without-ssl).

There are currently usages of common.hasCrypto which are not just for
detecting if crypto support is available and then skip the test in
question. For these case we still want to have a lint error generated
which can then be disabled using an ESLint comment.

PR-URL: https://github.com/nodejs/node/pull/13813
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Teddy Katz <teddy.katz@gmail.com>

2 files changed, 144 insertions, 0 deletions

diff --git a/tools/eslint-rules/crypto-check.js b/tools/eslint-rules/crypto-check.js
new file mode 100644
index 0000000000..b1b2a03f50
--- /dev/null
+++ b/tools/eslint-rules/crypto-check.js
@@ -0,0 +1,83 @@
+/**
+ * @fileoverview Check that common.hasCrypto is used if crypto, tls,
+ * https, or http2 modules are required.
+ *
+ * This rule can be ignored using // eslint-disable-line crypto-check
+ *
+ * @author Daniel Bevenius <daniel.bevenius@gmail.com>
+ */
+'use strict';
+
+const utils = require('./rules-utils.js');
+
+//------------------------------------------------------------------------------
+// Rule Definition
+//------------------------------------------------------------------------------
+const msg = 'Please add a hasCrypto check to allow this test to be skipped ' +
+            'when Node is built "--without-ssl".';
+
+module.exports = function(context) {
+  const missingCheckNodes = [];
+  const requireNodes = [];
+  var hasSkipCall = false;
+
+  function testCryptoUsage(node) {
+    if (utils.isRequired(node, ['crypto', 'tls', 'https', 'http2'])) {
+      requireNodes.push(node);
+    }
+  }
+
+  function testIfStatement(node) {
+    if (node.test.argument === undefined) {
+      return;
+    }
+    if (isCryptoCheck(node.test.argument)) {
+      checkCryptoCall(node);
+    }
+  }
+
+  function isCryptoCheck(node) {
+    return utils.usesCommonProperty(node, ['hasCrypto', 'hasFipsCrypto']);
+  }
+
+  function checkCryptoCall(node) {
+    if (utils.inSkipBlock(node)) {
+      hasSkipCall = true;
+    } else {
+      missingCheckNodes.push(node);
+    }
+  }
+
+  function testMemberExpression(node) {
+    if (isCryptoCheck(node)) {
+      checkCryptoCall(node);
+    }
+  }
+
+  function reportIfMissingCheck(node) {
+    if (hasSkipCall) {
+      return;
+    }
+
+    if (requireNodes.length > 0) {
+      if (missingCheckNodes.length > 0) {
+        report(missingCheckNodes);
+      } else {
+        report(requireNodes);
+      }
+    }
+  }
+
+  function report(nodes) {
+    nodes.forEach((node) => {
+      context.report(node, msg);
+    });
+  }
+
+  return {
+    'CallExpression': (node) => testCryptoUsage(node),
+    'IfStatement:exit': (node) => testIfStatement(node),
+    'MemberExpression:exit': (node) => testMemberExpression(node),
+    'Program:exit': (node) => reportIfMissingCheck(node)
+  };
+};
diff --git a/tools/eslint-rules/rules-utils.js b/tools/eslint-rules/rules-utils.js
new file mode 100644
index 0000000000..e3e5e6e5ef
--- /dev/null
+++ b/tools/eslint-rules/rules-utils.js
@@ -0,0 +1,61 @@
+/**
+ * Utility functions common to ESLint rules.
+ */
+'use strict';
+
+/**
+ * Returns true if any of the passed in modules are used in
+ * require calls.
+ */
+module.exports.isRequired = function(node, modules) {
+  return node.callee.name === 'require' &&
+    modules.includes(node.arguments[0].value);
+};
+
+/**
+ * Returns true is the node accesses any property in the properties
+ * array on the 'common' object.
+ */
+module.exports.usesCommonProperty = function(node, properties) {
+  if (node.name) {
+    return properties.includes(node.name);
+  }
+  if (node.property) {
+    return properties.includes(node.property.name);
+  }
+  return false;
+};
+
+/**
+ * Returns true if the passed in node is inside an if statement block,
+ * and the block also has a call to skip.
+ */
+module.exports.inSkipBlock = function(node) {
+  var hasSkipBlock = false;
+  if (node.test &&
+      node.test.type === 'UnaryExpression' &&
+      node.test.operator === '!') {
+    const consequent = node.consequent;
+    if (consequent.body) {
+      consequent.body.some(function(expressionStatement) {
+        if (hasSkip(expressionStatement.expression)) {
+          return hasSkipBlock = true;
+        }
+        return false;
+      });
+    } else {
+      if (hasSkip(consequent.expression)) {
+        hasSkipBlock = true;
+      }
+    }
+  }
+  return hasSkipBlock;
+};
+
+function hasSkip(expression) {
+  return expression &&
+         expression.callee &&
+         (expression.callee.name === 'skip' ||
+         expression.callee.property &&
+         expression.callee.property.name === 'skip');
+}