Don't run disabled lint rules

Summary:
We always generate all messages and then filter them out based on minimum severity.
It's lots of useless work, especially in commit hook mode where we are interested only in errors.

Test Plan:
  $ arc lint --cache 0 --severity error ArcanistXHPASTLinter.php
  0.406 s before, 0.074 after

Reviewers: epriestley

Reviewed By: epriestley

CC: aran, Korvin

Differential Revision: https://secure.phabricator.com/D4963

src/lint/ArcanistLintSeverity.php

@@ -33,9 +33,7 @@ final class ArcanistLintSeverity {
     return $map[$severity_code];
   }
 
-  public static function isAtLeastAsSevere(
+  public static function isAtLeastAsSevere($message_sev, $level) {
-    ArcanistLintMessage $message,
-    $level) {
 
     static $map = array(
       self::SEVERITY_DISABLED => 10,
@@ -45,7 +43,6 @@ final class ArcanistLintSeverity {
       self::SEVERITY_ERROR    => 40,
     );
 
-    $message_sev = $message->getSeverity();
     if (empty($map[$message_sev])) {
       return true;
     }

src/lint/engine/ArcanistLintEngine.php

@@ -247,9 +247,8 @@ abstract class ArcanistLintEngine {
     $this->didRunLinters($linters);
 
     foreach ($linters as $linter) {
-      $minimum = $this->minimumSeverity;
       foreach ($linter->getLintMessages() as $message) {
-        if (!ArcanistLintSeverity::isAtLeastAsSevere($message, $minimum)) {
+        if (!$this->isSeverityEnabled($message->getSeverity())) {
           continue;
         }
         if (!$this->isRelevantMessage($message)) {
@@ -307,6 +306,11 @@ abstract class ArcanistLintEngine {
     return $this->results;
   }
 
+  public function isSeverityEnabled($severity) {
+    $minimum = $this->minimumSeverity;
+    return ArcanistLintSeverity::isAtLeastAsSevere($severity, $minimum);
+  }
+
   private function shouldUseCache($cache_granularity, $repository_version) {
     switch ($cache_granularity) {
       case ArcanistLinter::GRANULARITY_FILE:

src/lint/linter/ArcanistLinter.php

@@ -226,6 +226,11 @@ abstract class ArcanistLinter {
     // This is a hook.
   }
 
+  protected function isCodeEnabled($code) {
+    $severity = $this->getLintMessageSeverity($code);
+    return $this->getEngine()->isSeverityEnabled($severity);
+  }
+
   public function getLintSeverityMap() {
     return array();
   }

src/lint/linter/ArcanistXHPASTLinter.php

@@ -175,34 +175,57 @@ final class ArcanistXHPASTLinter extends ArcanistBaseXHPASTLinter {
 
     $root = $this->trees[$path]->getRootNode();
 
-    $this->lintUseOfThisInStaticMethods($root);
+    $method_codes = array(
-    $this->lintDynamicDefines($root);
+      'lintStrstrUsedForCheck' => self::LINT_SLOWNESS,
-    $this->lintSurpriseConstructors($root);
+      'lintStrposUsedForStart' => self::LINT_SLOWNESS,
-    $this->lintPHPTagUse($root);
+      'lintPHP53Features' => self::LINT_PHP_53_FEATURES,
-    $this->lintVariableVariables($root);
+      'lintPHP54Features' => self::LINT_PHP_54_FEATURES,
-    $this->lintTODOComments($root);
+      'lintImplicitFallthrough' => self::LINT_IMPLICIT_FALLTHROUGH,
-    $this->lintExitExpressions($root);
+      'lintBraceFormatting' => self::LINT_BRACE_FORMATTING,
-    $this->lintSpaceAroundBinaryOperators($root);
+      'lintTautologicalExpressions' => self::LINT_TAUTOLOGICAL_EXPRESSION,
-    $this->lintSpaceAfterControlStatementKeywords($root);
+      'lintCommentSpaces' => self::LINT_COMMENT_SPACING,
-    $this->lintParenthesesShouldHugExpressions($root);
+      'lintHashComments' => self::LINT_COMMENT_STYLE,
-    $this->lintNamingConventions($root);
+      'lintReusedIterators' => self::LINT_REUSED_ITERATORS,
-    $this->lintPregQuote($root);
+      'lintVariableVariables' => self::LINT_VARIABLE_VARIABLE,
-    $this->lintUndeclaredVariables($root);
+      'lintUndeclaredVariables' => array(
-    $this->lintArrayIndexWhitespace($root);
+        self::LINT_EXTRACT_USE,
-    $this->lintCommentSpaces($root);
+        self::LINT_REUSED_AS_ITERATOR,
-    $this->lintHashComments($root);
+        self::LINT_UNDECLARED_VARIABLE,
-    $this->lintPrimaryDeclarationFilenameMatch($root);
+      ),
-    $this->lintTautologicalExpressions($root);
+      'lintPHPTagUse' => array(
-    $this->lintPlusOperatorOnStrings($root);
+        self::LINT_PHP_SHORT_TAG,
-    $this->lintDuplicateKeysInArray($root);
+        self::LINT_PHP_ECHO_TAG,
-    $this->lintReusedIterators($root);
+        self::LINT_PHP_OPEN_TAG,
-    $this->lintBraceFormatting($root);
+        self::LINT_PHP_CLOSE_TAG,
-    $this->lintRaggedClasstreeEdges($root);
+      ),
-    $this->lintImplicitFallthrough($root);
+      'lintNamingConventions' => self::LINT_NAMING_CONVENTIONS,
-    $this->lintPHP53Features($root);
+      'lintSurpriseConstructors' => self::LINT_IMPLICIT_CONSTRUCTOR,
-    $this->lintPHP54Features($root);
+      'lintParenthesesShouldHugExpressions' => self::LINT_PARENTHESES_SPACING,
-    $this->lintStrposUsedForStart($root);
+      'lintSpaceAfterControlStatementKeywords' =>
-    $this->lintStrstrUsedForCheck($root);
+        self::LINT_CONTROL_STATEMENT_SPACING,
+      'lintSpaceAroundBinaryOperators' => self::LINT_BINARY_EXPRESSION_SPACING,
+      'lintDynamicDefines' => self::LINT_DYNAMIC_DEFINE,
+      'lintUseOfThisInStaticMethods' => self::LINT_STATIC_THIS,
+      'lintPregQuote' => self::LINT_PREG_QUOTE_MISUSE,
+      'lintExitExpressions' => self::LINT_EXIT_EXPRESSION,
+      'lintArrayIndexWhitespace' => self::LINT_ARRAY_INDEX_SPACING,
+      'lintTODOComments' => self::LINT_TODO_COMMENT,
+      'lintPrimaryDeclarationFilenameMatch' =>
+        self::LINT_CLASS_FILENAME_MISMATCH,
+      'lintPlusOperatorOnStrings' => self::LINT_PLUS_OPERATOR_ON_STRINGS,
+      'lintDuplicateKeysInArray' => self::LINT_DUPLICATE_KEYS_IN_ARRAY,
+      'lintRaggedClasstreeEdges' => self::LINT_RAGGED_CLASSTREE_EDGE,
+    );
+
+    foreach ($method_codes as $method => $codes) {
+      foreach ((array)$codes as $code) {
+        if ($this->isCodeEnabled($code)) {
+          call_user_func(array($this, $method), $root);
+          break;
+        }
+      }
+    }
+
   }
 
   public function lintStrstrUsedForCheck($root) {