Merge pull request #27 from GitHubSecurityLab/refactor_astnode

Add Expression nodes and locations

Author: Alvaro Muñoz

.gitignore

@@ -3,3 +3,4 @@
 ql/lib/.codeql/
 ql/src/.codeql/
 ql/test/.codeql/
+db/

ql/lib/codeql/Locations.qll

@@ -1,6 +1,7 @@
 /** Provides classes for working with locations. */
 
 import files.FileSystem
+import codeql.actions.Ast
 
 bindingset[loc]
 pragma[inline_late]
@@ -11,30 +12,57 @@ private string locationToString(Location loc) {
   )
 }
 
+newtype TLocation =
+  TBaseLocation(string filepath, int startline, int startcolumn, int endline, int endcolumn) {
+    exists(File file |
+      file.getAbsolutePath() = filepath and
+      locations_default(_, file, startline, startcolumn, endline, endcolumn)
+    )
+    or
+    exists(ExpressionNode e |
+      e.hasLocationInfo(filepath, startline, startcolumn, endline, endcolumn)
+    )
+    or
+    filepath = "" and startline = 0 and startcolumn = 0 and endline = 0 and endcolumn = 0
+  }
+
 /**
  * A location as given by a file, a start line, a start column,
  * an end line, and an end column.
  *
  * For more information about locations see [Locations](https://codeql.github.com/docs/writing-codeql-queries/providing-locations-in-codeql-queries/).
  */
-class Location extends @location_default {
+class Location extends TLocation, TBaseLocation {
+  string filepath;
+  int startline;
+  int startcolumn;
+  int endline;
+  int endcolumn;
+
+  Location() { this = TBaseLocation(filepath, startline, startcolumn, endline, endcolumn) }
+
   /** Gets the file for this location. */
-  File getFile() { locations_default(this, result, _, _, _, _) }
+  File getFile() {
+    exists(File file |
+      file.getAbsolutePath() = filepath and
+      result = file
+    )
+  }
 
   /** Gets the 1-based line number (inclusive) where this location starts. */
-  int getStartLine() { locations_default(this, _, result, _, _, _) }
+  int getStartLine() { result = startline }
 
   /** Gets the 1-based column number (inclusive) where this location starts. */
-  int getStartColumn() { locations_default(this, _, _, result, _, _) }
+  int getStartColumn() { result = startcolumn }
 
-  /** Gets the 1-based line number (inclusive) where this location ends. */
-  int getEndLine() { locations_default(this, _, _, _, result, _) }
+  /** Gets the 1-based line number (inclusive) where this.getLocationDefault() location ends. */
+  int getEndLine() { result = endline }
 
-  /** Gets the 1-based column number (inclusive) where this location ends. */
-  int getEndColumn() { locations_default(this, _, _, _, _, result) }
+  /** Gets the 1-based column number (inclusive) where this.getLocationDefault() location ends. */
+  int getEndColumn() { result = endcolumn }
 
   /** Gets the number of lines covered by this location. */
-  int getNumLines() { result = this.getEndLine() - this.getStartLine() + 1 }
+  int getNumLines() { result = endline - startline + 1 }
 
   /** Gets a textual representation of this element. */
   pragma[inline]
@@ -47,13 +75,12 @@ class Location extends @location_default {
    * For more information, see
    * [Providing locations in CodeQL queries](https://codeql.github.com/docs/writing-codeql-queries/providing-locations-in-codeql-queries/).
    */
-  predicate hasLocationInfo(
-    string filepath, int startline, int startcolumn, int endline, int endcolumn
-  ) {
-    exists(File f |
-      locations_default(this, f, startline, startcolumn, endline, endcolumn) and
-      filepath = f.getAbsolutePath()
-    )
+  predicate hasLocationInfo(string p, int sl, int sc, int el, int ec) {
+    p = filepath and
+    sl = startline and
+    sc = startcolumn and
+    el = endline and
+    ec = endcolumn
   }
 
   /** Holds if this location starts strictly before the specified location. */