Move `View CFG` implementation from Ruby/Swift into shared library

csharp/ql/test/library-tests/controlflow/graph/NodeGraph.ql

@@ -4,6 +4,9 @@
 
 import csharp
 import Common
-import semmle.code.csharp.controlflow.internal.ControlFlowGraphImpl::TestOutput
 
-private class MyRelevantNode extends RelevantNode, SourceControlFlowNode { }
+private class MyRelevantNode extends SourceControlFlowNode {
+  string getOrderDisambiguation() { result = "" }
+}
+
+import semmle.code.csharp.controlflow.internal.ControlFlowGraphImpl::TestOutput<MyRelevantNode>

ruby/ql/lib/ide-contextual-queries/printCfg.ql

@@ -7,47 +7,35 @@
  * @tags ide-contextual-queries/print-cfg
  */
 
-private import codeql.ruby.controlflow.internal.ControlFlowGraphImpl::TestOutput
-private import codeql.IDEContextual
 private import codeql.Locations
+private import codeql.ruby.controlflow.internal.ControlFlowGraphImpl
 private import codeql.ruby.controlflow.ControlFlowGraph
 
-/**
- * Gets the source file to generate a CFG from.
- */
 external string selectedSourceFile();
 
-external string selectedSourceLine();
+private predicate selectedSourceFileAlias = selectedSourceFile/0;
 
-external string selectedSourceColumn();
+external int selectedSourceLine();
 
-bindingset[file, line, column]
-private CfgScope smallestEnclosingScope(File file, int line, int column) {
-  result =
-    min(Location loc, CfgScope scope |
-      loc = scope.getLocation() and
-      (
-        loc.getStartLine() < line
-        or
-        loc.getStartLine() = line and loc.getStartColumn() <= column
-      ) and
-      (
-        loc.getEndLine() > line
-        or
-        loc.getEndLine() = line and loc.getEndColumn() >= column
-      ) and
-      loc.getFile() = file
-    |
-      scope
-      order by
-        loc.getStartLine() desc, loc.getStartColumn() desc, loc.getEndLine(), loc.getEndColumn()
-    )
-}
+private predicate selectedSourceLineAlias = selectedSourceLine/0;
 
-class MyRelevantNode extends RelevantNode {
-  MyRelevantNode() {
-    this.getScope() =
-      smallestEnclosingScope(getFileBySourceArchiveName(selectedSourceFile()),
-        selectedSourceLine().toInt(), selectedSourceColumn().toInt())
+external int selectedSourceColumn();
+
+private predicate selectedSourceColumnAlias = selectedSourceColumn/0;
+
+module ViewCfgQueryInput implements ViewCfgQueryInputSig<File> {
+  predicate selectedSourceFile = selectedSourceFileAlias/0;
+
+  predicate selectedSourceLine = selectedSourceLineAlias/0;
+
+  predicate selectedSourceColumn = selectedSourceColumnAlias/0;
+
+  predicate cfgScopeSpan(
+    CfgScope scope, File file, int startLine, int startColumn, int endLine, int endColumn
+  ) {
+    file = scope.getFile() and
+    scope.getLocation().hasLocationInfo(_, startLine, startColumn, endLine, endColumn)
   }
 }
+
+import ViewCfgQuery<File, ViewCfgQueryInput>

ruby/ql/test/library-tests/controlflow/graph/Cfg.ql

@@ -3,8 +3,9 @@
  */
 
 import codeql.ruby.CFG
-import codeql.ruby.controlflow.internal.ControlFlowGraphImpl::TestOutput
 
-class MyRelevantNode extends RelevantNode {
-  MyRelevantNode() { exists(this) }
+class MyRelevantNode extends CfgNode {
+  string getOrderDisambiguation() { result = "" }
 }
+
+import codeql.ruby.controlflow.internal.ControlFlowGraphImpl::TestOutput<MyRelevantNode>

shared/controlflow/codeql/controlflow/Cfg.qll

@@ -4,6 +4,7 @@
  */
 
 private import codeql.util.Location
+private import codeql.util.FileSystem
 
 /** Provides the language-specific input specification. */
 signature module InputSig<LocationSig Location> {
@@ -1132,19 +1133,19 @@ module Make<LocationSig Location, InputSig<Location> Input> {
 
   final class AstCfgNode = AstCfgNodeImpl;
 
+  /** A node to be included in the output of `TestOutput`. */
+  signature class RelevantNodeSig extends Node {
+    /**
+     * Gets a string used to resolve ties in node and edge ordering.
+     */
+    string getOrderDisambiguation();
+  }
+
   /**
    * Import this module into a `.ql` file of `@kind graph` to render a CFG. The
    * graph is restricted to nodes from `RelevantNode`.
    */
-  module TestOutput {
-    /** A CFG node to include in the output. */
-    abstract class RelevantNode extends Node {
-      /**
-       * Gets a string used to resolve ties in node and edge ordering.
-       */
-      string getOrderDisambiguation() { result = "" }
-    }
-
+  module TestOutput<RelevantNodeSig RelevantNode> {
     /** Holds if `n` is a relevant node in the CFG. */
     query predicate nodes(RelevantNode n, string attr, string val) {
       attr = "semmle.order" and
@@ -1192,6 +1193,78 @@ module Make<LocationSig Location, InputSig<Location> Input> {
     }
   }
 
+  /** Provides the input to `ViewCfgQuery`. */
+  signature module ViewCfgQueryInputSig<FileSig File> {
+    /** The source file selected in the IDE. Should be an `external` predicate. */
+    string selectedSourceFile();
+
+    /** The source line selected in the IDE. Should be an `external` predicate. */
+    int selectedSourceLine();
+
+    /** The source column selected in the IDE. Should be an `external` predicate. */
+    int selectedSourceColumn();
+
+    /**
+     * Holds if CFG scope `scope` spans column `startColumn` of line `startLine` to
+     * column `endColumn` of line `endLine` in `file`.
+     */
+    predicate cfgScopeSpan(
+      CfgScope scope, File file, int startLine, int startColumn, int endLine, int endColumn
+    );
+  }
+
+  /**
+   * Provides an implementation for a `View CFG` query.
+   *
+   * Import this module into a `.ql` that looks like
+   *
+   * ```ql
+   * @name Print CFG
+   * @description Produces a representation of a file's Control Flow Graph.
+   *              This query is used by the VS Code extension.
+   * @id <lang>/print-cfg
+   * @kind graph
+   * @tags ide-contextual-queries/print-cfg
+   * ```
+   */
+  module ViewCfgQuery<FileSig File, ViewCfgQueryInputSig<File> ViewCfgQueryInput> {
+    private import ViewCfgQueryInput
+
+    bindingset[file, line, column]
+    private CfgScope smallestEnclosingScope(File file, int line, int column) {
+      result =
+        min(CfgScope scope, int startLine, int startColumn, int endLine, int endColumn |
+          cfgScopeSpan(scope, file, startLine, startColumn, endLine, endColumn) and
+          (
+            startLine < line
+            or
+            startLine = line and startColumn <= column
+          ) and
+          (
+            endLine > line
+            or
+            endLine = line and endColumn >= column
+          )
+        |
+          scope order by startLine desc, startColumn desc, endLine, endColumn
+        )
+    }
+
+    private import IdeContextual<File>
+
+    private class RelevantNode extends Node {
+      RelevantNode() {
+        this.getScope() =
+          smallestEnclosingScope(getFileBySourceArchiveName(selectedSourceFile()),
+            selectedSourceLine(), selectedSourceColumn())
+      }
+
+      string getOrderDisambiguation() { result = "" }
+    }
+
+    import TestOutput<RelevantNode>
+  }
+
   /** Provides a set of consistency queries. */
   module Consistency {
     /** Holds if `s1` and `s2` are distinct representations of the same set. */

swift/ql/lib/codeql/swift/controlflow/internal/PrintCFG.ql

@@ -7,52 +7,45 @@
  * @tags ide-contextual-queries/print-cfg
  */
 
-private import codeql.IDEContextual
+private import codeql.swift.elements.File
 private import codeql.swift.controlflow.ControlFlowGraph
-private import codeql.swift.controlflow.internal.ControlFlowGraphImpl::TestOutput
+private import codeql.swift.controlflow.internal.ControlFlowGraphImpl as Impl
+private import codeql.swift.controlflow.internal.ControlFlowGraphImplSpecific
 
 /**
  * Gets the source file to generate a CFG from.
  */
 external string selectedSourceFile();
 
+private predicate selectedSourceFileAlias = selectedSourceFile/0;
+
 /**
  * Gets the source line to generate a CFG from.
  */
-external string selectedSourceLine();
+external int selectedSourceLine();
+
+private predicate selectedSourceLineAlias = selectedSourceLine/0;
 
 /**
  * Gets the source column to generate a CFG from.
  */
-external string selectedSourceColumn();
+external int selectedSourceColumn();
 
-bindingset[file, line, column]
-private CfgScope smallestEnclosingScope(File file, int line, int column) {
-  result =
-    min(Location loc, CfgScope scope |
-      loc = scope.getLocation() and
-      (
-        loc.getStartLine() < line
-        or
-        loc.getStartLine() = line and loc.getStartColumn() <= column
-      ) and
-      (
-        loc.getEndLine() > line
-        or
-        loc.getEndLine() = line and loc.getEndColumn() >= column
-      ) and
-      loc.getFile() = file
-    |
-      scope
-      order by
-        loc.getStartLine() desc, loc.getStartColumn() desc, loc.getEndLine(), loc.getEndColumn()
-    )
-}
+private predicate selectedSourceColumnAlias = selectedSourceColumn/0;
 
-class MyRelevantNode extends RelevantNode {
-  MyRelevantNode() {
-    this.getScope() =
-      smallestEnclosingScope(getFileBySourceArchiveName(selectedSourceFile()),
-        selectedSourceLine().toInt(), selectedSourceColumn().toInt())
+module ViewCfgQueryInput implements Impl::ViewCfgQueryInputSig<File> {
+  predicate selectedSourceFile = selectedSourceFileAlias/0;
+
+  predicate selectedSourceLine = selectedSourceLineAlias/0;
+
+  predicate selectedSourceColumn = selectedSourceColumnAlias/0;
+
+  predicate cfgScopeSpan(
+    CfgInput::CfgScope scope, File file, int startLine, int startColumn, int endLine, int endColumn
+  ) {
+    file = scope.getFile() and
+    scope.getLocation().hasLocationInfo(_, startLine, startColumn, endLine, endColumn)
   }
 }
+
+import Impl::ViewCfgQuery<File, ViewCfgQueryInput>

swift/ql/test/library-tests/controlflow/graph/Cfg.ql

@@ -4,16 +4,17 @@
 
 import swift
 import codeql.swift.controlflow.ControlFlowGraph
-import codeql.swift.controlflow.internal.ControlFlowGraphImpl::TestOutput
 
-class MyRelevantNode extends RelevantNode {
+class MyRelevantNode extends ControlFlowNode {
   MyRelevantNode() { this.getScope().getLocation().getFile().getName().matches("%swift/ql/test%") }
 
   private AstNode asAstNode() { result = this.getAstNode().asAstNode() }
 
-  override string getOrderDisambiguation() {
+  string getOrderDisambiguation() {
     result = this.asAstNode().getPrimaryQlClasses()
     or
     not exists(this.asAstNode()) and result = ""
   }
 }
+
+import codeql.swift.controlflow.internal.ControlFlowGraphImpl::TestOutput<MyRelevantNode>