Go: Refactor Location implementation

hvitved · hvitved · commit 7c3a6f86b4e7 · 2025-02-27T09:37:23.000+01:00
diff --git a/go/ql/lib/semmle/go/Locations.qll b/go/ql/lib/semmle/go/Locations.qll
@@ -3,6 +3,21 @@
 import go
 private import internal.Locations
 
+private module DbLocationInput implements LocationClassInputSig {
+  class Base = TDbLocation;
+
+  predicate locationInfo(
+    Base b, string filepath, int startline, int startcolumn, int endline, int endcolumn
+  ) {
+    exists(File f |
+      dbLocationInfo(b, f, startline, startcolumn, endline, endcolumn) and
+      filepath = f.getAbsolutePath()
+    )
+  }
+
+  File getFile(Base b) { dbLocationInfo(b, result, _, _, _, _) }
+}
+
 /**
  * A location as given by a file, a start line, a start column,
  * an end line, and an end column.
@@ -11,51 +26,21 @@ private import internal.Locations
  *
  * For more information about locations see [Locations](https://codeql.github.com/docs/writing-codeql-queries/providing-locations-in-codeql-queries/).
  */
-class DbLocation extends TDbLocation {
-  /** Gets the file for this location. */
-  File getFile() { dbLocationInfo(this, result, _, _, _, _) }
-
-  /** Gets the 1-based line number (inclusive) where this location starts. */
-  int getStartLine() { dbLocationInfo(this, _, result, _, _, _) }
-
-  /** Gets the 1-based column number (inclusive) where this location starts. */
-  int getStartColumn() { dbLocationInfo(this, _, _, result, _, _) }
-
-  /** Gets the 1-based line number (inclusive) where this location ends. */
-  int getEndLine() { dbLocationInfo(this, _, _, _, result, _) }
+class DbLocation = LocationClass<DbLocationInput>::Location;
 
-  /** Gets the 1-based column number (inclusive) where this location ends. */
-  int getEndColumn() { dbLocationInfo(this, _, _, _, _, result) }
-
-  /** Gets the number of lines covered by this location. */
-  int getNumLines() { result = this.getEndLine() - this.getStartLine() + 1 }
-
-  /** Gets a textual representation of this element. */
-  string toString() {
-    exists(string filepath, int startline, int startcolumn, int endline, int endcolumn |
-      this.hasLocationInfo(filepath, startline, startcolumn, endline, endcolumn) and
-      result = filepath + "@" + startline + ":" + startcolumn + ":" + endline + ":" + endcolumn
-    )
-  }
+private module LocationInput implements LocationClassInputSig {
+  class Base = TLocation;
 
-  /**
-   * Holds if this element is at the specified location.
-   * The location spans column `startcolumn` of line `startline` to
-   * column `endcolumn` of line `endline` in file `filepath`.
-   * For more information, see
-   * [Locations](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
+  predicate locationInfo(
+    Base b, string filepath, int startline, int startcolumn, int endline, int endcolumn
   ) {
-    exists(File f |
-      dbLocationInfo(this, f, startline, startcolumn, endline, endcolumn) and
-      filepath = f.getAbsolutePath()
-    )
+    dataFlowNodeLocationInfo(b, filepath, startline, startcolumn, endline, endcolumn)
   }
+
+  File getFile(Base b) { dataFlowNodeLocationInfo(b, result.getAbsolutePath(), _, _, _, _) }
 }
 
-final class Location = LocationImpl;
+class Location = LocationClass<LocationInput>::Location;
 
 /** A program element with a location. */
 class Locatable extends @locatable {
diff --git a/go/ql/lib/semmle/go/dataflow/internal/DataFlowNodes.qll b/go/ql/lib/semmle/go/dataflow/internal/DataFlowNodes.qll
@@ -4,6 +4,7 @@ private import semmle.go.dataflow.FlowSummary
 private import DataFlowPrivate
 private import FlowSummaryImpl as FlowSummaryImpl
 private import semmle.go.dataflow.ExternalFlow
+private import semmle.go.internal.Locations
 
 cached
 private newtype TNode =
@@ -158,12 +159,7 @@ module Public {
     }
 
     /** Gets the location of this node. */
-    Location getLocation() {
-      exists(string filepath, int startline, int startcolumn, int endline, int endcolumn |
-        this.hasLocationInfo(filepath, startline, startcolumn, endline, endcolumn) and
-        result.hasLocationInfo(filepath, startline, startcolumn, endline, endcolumn)
-      )
-    }
+    Location getLocation() { result = getDataFlowNodeLocation(this) }
 
     /** Gets the file in which this node appears. */
     File getFile() { this.hasLocationInfo(result.getAbsolutePath(), _, _, _, _) }
diff --git a/go/ql/lib/semmle/go/internal/Locations.qll b/go/ql/lib/semmle/go/internal/Locations.qll
@@ -2,13 +2,76 @@
 
 import go
 
+/** Provides the input to `LocationClass`. */
+signature module LocationClassInputSig {
+  class Base;
+
+  predicate locationInfo(
+    Base b, string filepath, int startline, int startcolumn, int endline, int endcolumn
+  );
+
+  File getFile(Base b);
+}
+
+/** Provides a class layer for locations. */
+module LocationClass<LocationClassInputSig Input> {
+  private import Input
+
+  /**
+   * 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/).
+   */
+  final class Location instanceof Base {
+    /** Gets the file for this location. */
+    File getFile() { result = getFile(this) }
+
+    /** Gets the 1-based line number (inclusive) where this location starts. */
+    int getStartLine() { locationInfo(this, _, result, _, _, _) }
+
+    /** Gets the 1-based column number (inclusive) where this location starts. */
+    int getStartColumn() { locationInfo(this, _, _, result, _, _) }
+
+    /** Gets the 1-based line number (inclusive) where this location ends. */
+    int getEndLine() { locationInfo(this, _, _, _, result, _) }
+
+    /** Gets the 1-based column number (inclusive) where this location ends. */
+    int getEndColumn() { locationInfo(this, _, _, _, _, result) }
+
+    /** Gets the number of lines covered by this location. */
+    int getNumLines() { result = this.getEndLine() - this.getStartLine() + 1 }
+
+    /** Gets a textual representation of this element. */
+    string toString() {
+      exists(string filepath, int startline, int startcolumn, int endline, int endcolumn |
+        this.hasLocationInfo(filepath, startline, startcolumn, endline, endcolumn) and
+        result = filepath + "@" + startline + ":" + startcolumn + ":" + endline + ":" + endcolumn
+      )
+    }
+
+    /**
+     * Holds if this element is at the specified location.
+     * The location spans column `startcolumn` of line `startline` to
+     * column `endcolumn` of line `endline` in file `filepath`.
+     * For more information, see
+     * [Locations](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
+    ) {
+      locationInfo(this, filepath, startline, startcolumn, endline, endcolumn)
+    }
+  }
+}
+
 // Should _not_ be cached, as that would require the data flow stage to be evaluated
 // in order to evaluate the AST stage. Ideally, we would cache each injector separately,
 // but that's not possible. Instead, we cache all predicates that need the injectors
 // to be tuple numbered.
 newtype TLocation =
   TDbLocation(@location loc) or
-  TSynthLocation(string filepath, int startline, int startcolumn, int endline, int endcolumn) {
+  TDataFlowNodeLocation(string filepath, int startline, int startcolumn, int endline, int endcolumn) {
     any(DataFlow::Node n).hasLocationInfo(filepath, startline, startcolumn, endline, endcolumn) and
     // avoid overlap with existing DB locations
     not existingDBLocation(filepath, startline, startcolumn, endline, endcolumn)
@@ -24,91 +87,6 @@ private predicate existingDBLocation(
   )
 }
 
-/**
- * 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/).
- */
-abstract class LocationImpl extends TLocation {
-  /** Gets the file for this location. */
-  abstract File getFile();
-
-  /** Gets the 1-based line number (inclusive) where this location starts. */
-  abstract int getStartLine();
-
-  /** Gets the 1-based column number (inclusive) where this location starts. */
-  abstract int getStartColumn();
-
-  /** Gets the 1-based line number (inclusive) where this location ends. */
-  abstract int getEndLine();
-
-  /** Gets the 1-based column number (inclusive) where this location ends. */
-  abstract int getEndColumn();
-
-  /** Gets the number of lines covered by this location. */
-  int getNumLines() { result = this.getEndLine() - this.getStartLine() + 1 }
-
-  /** Gets a textual representation of this element. */
-  string toString() {
-    exists(string filepath, int startline, int startcolumn, int endline, int endcolumn |
-      this.hasLocationInfo(filepath, startline, startcolumn, endline, endcolumn) and
-      result = filepath + "@" + startline + ":" + startcolumn + ":" + endline + ":" + endcolumn
-    )
-  }
-
-  /**
-   * Holds if this element is at the specified location.
-   * The location spans column `startcolumn` of line `startline` to
-   * column `endcolumn` of line `endline` in file `filepath`.
-   * For more information, see
-   * [Locations](https://codeql.github.com/docs/writing-codeql-queries/providing-locations-in-codeql-queries/).
-   */
-  abstract predicate hasLocationInfo(
-    string filepath, int startline, int startcolumn, int endline, int endcolumn
-  );
-}
-
-class DbLocationImpl extends LocationImpl instanceof DbLocation {
-  private @location loc;
-
-  DbLocationImpl() { this = TDbLocation(loc) }
-
-  override File getFile() { result = DbLocation.super.getFile() }
-
-  override int getStartLine() { result = DbLocation.super.getStartLine() }
-
-  override int getStartColumn() { result = DbLocation.super.getStartColumn() }
-
-  override int getEndLine() { result = DbLocation.super.getEndLine() }
-
-  override int getEndColumn() { result = DbLocation.super.getEndColumn() }
-
-  override predicate hasLocationInfo(
-    string filepath, int startline, int startcolumn, int endline, int endcolumn
-  ) {
-    DbLocation.super.hasLocationInfo(filepath, startline, startcolumn, endline, endcolumn)
-  }
-}
-
-class SynthLocationImpl extends LocationImpl, TSynthLocation {
-  override File getFile() { synthLocationInfo(this, result.getAbsolutePath(), _, _, _, _) }
-
-  override int getStartLine() { synthLocationInfo(this, _, result, _, _, _) }
-
-  override int getStartColumn() { synthLocationInfo(this, _, _, result, _, _) }
-
-  override int getEndLine() { synthLocationInfo(this, _, _, _, result, _) }
-
-  override int getEndColumn() { synthLocationInfo(this, _, _, _, _, result) }
-
-  override predicate hasLocationInfo(
-    string filepath, int startline, int startcolumn, int endline, int endcolumn
-  ) {
-    synthLocationInfo(this, filepath, startline, startcolumn, endline, endcolumn)
-  }
-}
-
 cached
 private module Cached {
   cached
@@ -143,8 +121,21 @@ private module Cached {
 import Cached
 
 cached
-private predicate synthLocationInfo(
-  SynthLocationImpl l, string filepath, int startline, int startcolumn, int endline, int endcolumn
-) {
-  l = TSynthLocation(filepath, startline, startcolumn, endline, endcolumn)
+private module DataFlowNodes {
+  cached
+  predicate dataFlowNodeLocationInfo(
+    Location l, string filepath, int startline, int startcolumn, int endline, int endcolumn
+  ) {
+    l = TDataFlowNodeLocation(filepath, startline, startcolumn, endline, endcolumn)
+  }
+
+  cached
+  Location getDataFlowNodeLocation(DataFlow::Node n) {
+    exists(string filepath, int startline, int startcolumn, int endline, int endcolumn |
+      n.hasLocationInfo(filepath, startline, startcolumn, endline, endcolumn) and
+      result.hasLocationInfo(filepath, startline, startcolumn, endline, endcolumn)
+    )
+  }
 }
+
+import DataFlowNodes
