Python: Use shared FileSystem library.

Author: aschackmull

python/ql/lib/semmle/python/Files.qll

@@ -1,7 +1,32 @@
+/** Provides classes for working with files and folders. */
+
 import python
+private import codeql.util.FileSystem
+
+private module Input implements InputSig {
+  abstract class ContainerBase extends @container {
+    abstract string getAbsolutePath();
+
+    ContainerBase getParentContainer() { containerparent(result, this) }
+
+    string toString() { result = this.getAbsolutePath() }
+  }
+
+  class FolderBase extends ContainerBase, @folder {
+    override string getAbsolutePath() { folders(this, result) }
+  }
+
+  class FileBase extends ContainerBase, @file {
+    override string getAbsolutePath() { files(this, result) }
+  }
+
+  predicate hasSourceLocationPrefix = sourceLocationPrefix/1;
+}
+
+private module Impl = Make<Input>;
 
 /** A file */
-class File extends Container, @file {
+class File extends Container, Impl::File {
   /**
    * Holds if this element is at the specified location.
    * The location spans column `startcolumn` of line `startline` to
@@ -45,11 +70,6 @@ class File extends Container, @file {
     )
   }
 
-  override string getAbsolutePath() { files(this, result) }
-
-  /** Gets the URL of this file. */
-  override string getURL() { result = "file://" + this.getAbsolutePath() + ":0:0:0:0" }
-
   override Container getImportRoot(int n) {
     /* File stem must be a legal Python identifier */
     this.getStem().regexpMatch("[^\\d\\W]\\w*") and
@@ -108,7 +128,7 @@ private predicate occupied_line(File f, int n) {
 }
 
 /** A folder (directory) */
-class Folder extends Container, @folder {
+class Folder extends Container, Impl::Folder {
   /**
    * Holds if this element is at the specified location.
    * The location spans column `startcolumn` of line `startline` to
@@ -126,11 +146,6 @@ class Folder extends Container, @folder {
     endcolumn = 0
   }
 
-  override string getAbsolutePath() { folders(this, result) }
-
-  /** Gets the URL of this folder. */
-  override string getURL() { result = "folder://" + this.getAbsolutePath() }
-
   override Container getImportRoot(int n) {
     this.isImportRoot(n) and result = this
     or
@@ -144,34 +159,8 @@ class Folder extends Container, @folder {
  * A container is an abstract representation of a file system object that can
  * hold elements of interest.
  */
-abstract class Container extends @container {
-  Container getParent() { containerparent(result, this) }
-
-  /**
-   * Gets a textual representation of the path of this container.
-   *
-   * This is the absolute path of the container.
-   */
-  string toString() { result = this.getAbsolutePath() }
-
-  /**
-   * Gets the relative path of this file or folder from the root folder of the
-   * analyzed source location. The relative path of the root folder itself is
-   * the empty string.
-   *
-   * This has no result if the container is outside the source root, that is,
-   * if the root folder is not a reflexive, transitive parent of this container.
-   */
-  string getRelativePath() {
-    exists(string absPath, string pref |
-      absPath = this.getAbsolutePath() and sourceLocationPrefix(pref)
-    |
-      absPath = pref and result = ""
-      or
-      absPath = pref.regexpReplaceAll("/$", "") + "/" + result and
-      not result.matches("/%")
-    )
-  }
+class Container extends Impl::Container {
+  Container getParent() { result = this.getParentContainer() }
 
   /** Whether this file or folder is part of the standard library */
   predicate inStdlib() { this.inStdlib(_, _) }
@@ -187,135 +176,13 @@ abstract class Container extends @container {
     )
   }
 
-  /* Standard cross-language API */
-  /** Gets a file or sub-folder in this container. */
-  Container getAChildContainer() { containerparent(this, result) }
-
-  /** Gets a file in this container. */
-  File getAFile() { result = this.getAChildContainer() }
-
-  /** Gets a sub-folder in this container. */
-  Folder getAFolder() { result = this.getAChildContainer() }
-
-  /**
-   * Gets the absolute, canonical path of this container, using forward slashes
-   * as path separator.
-   *
-   * The path starts with a _root prefix_ followed by zero or more _path
-   * segments_ separated by forward slashes.
-   *
-   * The root prefix is of one of the following forms:
-   *
-   *   1. A single forward slash `/` (Unix-style)
-   *   2. An upper-case drive letter followed by a colon and a forward slash,
-   *      such as `C:/` (Windows-style)
-   *   3. Two forward slashes, a computer name, and then another forward slash,
-   *      such as `//FileServer/` (UNC-style)
-   *
-   * Path segments are never empty (that is, absolute paths never contain two
-   * contiguous slashes, except as part of a UNC-style root prefix). Also, path
-   * segments never contain forward slashes, and no path segment is of the
-   * form `.` (one dot) or `..` (two dots).
-   *
-   * Note that an absolute path never ends with a forward slash, except if it is
-   * a bare root prefix, that is, the path has no path segments. A container
-   * whose absolute path has no segments is always a `Folder`, not a `File`.
-   */
-  abstract string getAbsolutePath();
-
-  /**
-   * Gets the base name of this container including extension, that is, the last
-   * segment of its absolute path, or the empty string if it has no segments.
-   *
-   * Here are some examples of absolute paths and the corresponding base names
-   * (surrounded with quotes to avoid ambiguity):
-   *
-   * <table border="1">
-   * <tr><th>Absolute path</th><th>Base name</th></tr>
-   * <tr><td>"/tmp/tst.py"</td><td>"tst.py"</td></tr>
-   * <tr><td>"C:/Program Files (x86)"</td><td>"Program Files (x86)"</td></tr>
-   * <tr><td>"/"</td><td>""</td></tr>
-   * <tr><td>"C:/"</td><td>""</td></tr>
-   * <tr><td>"D:/"</td><td>""</td></tr>
-   * <tr><td>"//FileServer/"</td><td>""</td></tr>
-   * </table>
-   */
-  string getBaseName() {
-    result = this.getAbsolutePath().regexpCapture(".*/(([^/]*?)(?:\\.([^.]*))?)", 1)
-  }
-
-  /**
-   * Gets the extension of this container, that is, the suffix of its base name
-   * after the last dot character, if any.
-   *
-   * In particular,
-   *
-   *  - if the name does not include a dot, there is no extension, so this
-   *    predicate has no result;
-   *  - if the name ends in a dot, the extension is the empty string;
-   *  - if the name contains multiple dots, the extension follows the last dot.
-   *
-   * Here are some examples of absolute paths and the corresponding extensions
-   * (surrounded with quotes to avoid ambiguity):
-   *
-   * <table border="1">
-   * <tr><th>Absolute path</th><th>Extension</th></tr>
-   * <tr><td>"/tmp/tst.py"</td><td>"py"</td></tr>
-   * <tr><td>"/tmp/.gitignore"</td><td>"gitignore"</td></tr>
-   * <tr><td>"/bin/bash"</td><td>not defined</td></tr>
-   * <tr><td>"/tmp/tst2."</td><td>""</td></tr>
-   * <tr><td>"/tmp/x.tar.gz"</td><td>"gz"</td></tr>
-   * </table>
-   */
-  string getExtension() {
-    result = this.getAbsolutePath().regexpCapture(".*/([^/]*?)(\\.([^.]*))?", 3)
-  }
-
-  /**
-   * Gets the stem of this container, that is, the prefix of its base name up to
-   * (but not including) the last dot character if there is one, or the entire
-   * base name if there is not.
-   *
-   * Here are some examples of absolute paths and the corresponding stems
-   * (surrounded with quotes to avoid ambiguity):
-   *
-   * <table border="1">
-   * <tr><th>Absolute path</th><th>Stem</th></tr>
-   * <tr><td>"/tmp/tst.py"</td><td>"tst"</td></tr>
-   * <tr><td>"/tmp/.gitignore"</td><td>""</td></tr>
-   * <tr><td>"/bin/bash"</td><td>"bash"</td></tr>
-   * <tr><td>"/tmp/tst2."</td><td>"tst2"</td></tr>
-   * <tr><td>"/tmp/x.tar.gz"</td><td>"x.tar"</td></tr>
-   * </table>
-   */
-  string getStem() {
-    result = this.getAbsolutePath().regexpCapture(".*/([^/]*?)(?:\\.([^.]*))?", 1)
-  }
-
-  File getFile(string baseName) {
-    result = this.getAFile() and
-    result.getBaseName() = baseName
-  }
-
-  Folder getFolder(string baseName) {
-    result = this.getAFolder() and
-    result.getBaseName() = baseName
-  }
-
-  Container getParentContainer() { this = result.getAChildContainer() }
+  override Container getParentContainer() { result = super.getParentContainer() }
 
   Container getChildContainer(string baseName) {
     result = this.getAChildContainer() and
     result.getBaseName() = baseName
   }
 
-  /**
-   * Gets a URL representing the location of this container.
-   *
-   * For more information see [Providing URLs](https://codeql.github.com/docs/writing-codeql-queries/providing-locations-in-codeql-queries/#providing-urls).
-   */
-  abstract string getURL();
-
   /** Holds if this folder is on the import path. */
   predicate isImportRoot() { this.isImportRoot(_) }