Unified: Implement simple LOC counting

unified/ql/lib/codeql/files/FileSystem.qll

@@ -2,6 +2,7 @@
 overlay[local]
 module;
 
+private import unified
 private import codeql.Locations
 private import codeql.util.FileSystem
 
@@ -37,4 +38,23 @@ module Folder = Impl::Folder;
 class File extends Container, Impl::File {
   /** Holds if this file was extracted from ordinary source code. */
   predicate fromSource() { any() }
+
+  /**
+   * Gets the number of lines containing code in this file. This value
+   * is approximate.
+   */
+  overlay[local?]
+  int getNumberOfLinesOfCode() {
+    result =
+      count(int line |
+        exists(AstNode node, Location loc |
+          not node instanceof Comment and
+          not node instanceof TopLevel and
+          loc = node.getLocation() and
+          this = loc.getFile() and
+          line = loc.getStartLine() and
+          not loc instanceof EmptyLocation
+        )
+      )
+  }
 }

unified/ql/src/diagnostic/ExtractorInformation.ql

@@ -9,9 +9,37 @@
 private import unified
 private import codeql.unified.internal.AnalysisQuality
 
+predicate fileCount(string key, int value) {
+  key = "Number of files" and
+  value = strictcount(File f)
+}
+
+predicate fileCountByExtension(string key, int value) {
+  exists(string extension |
+    key = "Number of files with extension " + extension and
+    value = strictcount(File f | f.getExtension() = extension)
+  )
+}
+
+predicate numberOfLinesOfCode(string key, int value) {
+  key = "Number of lines of code" and
+  value = strictsum(File f | any() | f.getNumberOfLinesOfCode())
+}
+
+predicate numberOfLinesOfCodeByExtension(string key, int value) {
+  exists(string extension |
+    key = "Number of lines of code with extension " + extension and
+    value = strictsum(File f | f.getExtension() = extension | f.getNumberOfLinesOfCode())
+  )
+}
+
 from string key, float value
 where
   (
+    fileCount(key, value) or
+    fileCountByExtension(key, value) or
+    numberOfLinesOfCode(key, value) or
+    numberOfLinesOfCodeByExtension(key, value) or
     StaticNameResolutionStatsReport::keyValuePair(key, value) or
     FilesCoveredByModuleManifestStatsReport::keyValuePair(key, value)
   ) and