JS: Add internal extension of PackageJson class

Author: asgerf

javascript/ql/lib/semmle/javascript/internal/paths/PackageJsonEx.qll

@@ -0,0 +1,85 @@
+private import javascript
+private import semmle.javascript.internal.paths.JSPaths
+
+/**
+ * Extension of `PackageJson` with some internal path-resolution predicates.
+ */
+class PackageJsonEx extends PackageJson {
+  private JsonValue getAPartOfExportsSection(string pattern) {
+    result = this.getPropValue("exports") and
+    pattern = ""
+    or
+    exists(string prop, string prevPath |
+      result = this.getAPartOfExportsSection(prevPath).getPropValue(prop) and
+      if prop.matches("./%") then pattern = prop.suffix(2) else pattern = prevPath
+    )
+  }
+
+  predicate hasPathMapping(string pattern, string newPath) {
+    this.getAPartOfExportsSection(pattern).getStringValue() = newPath
+  }
+
+  predicate hasExactPathMapping(string pattern, string newPath) {
+    this.getAPartOfExportsSection(pattern).getStringValue() = newPath and
+    not pattern.matches("%*%")
+  }
+
+  predicate hasPrefixPathMapping(string pattern, string newPath) {
+    this.hasPathMapping(pattern + "*", newPath + "*")
+  }
+
+  predicate hasExactPathMappingTo(string pattern, Container target) {
+    exists(string newPath |
+      this.hasExactPathMapping(pattern, newPath) and
+      target = Resolver::resolve(this.getFolder(), newPath)
+    )
+  }
+
+  predicate hasPrefixPathMappingTo(string pattern, Container target) {
+    exists(string newPath |
+      this.hasPrefixPathMapping(pattern, newPath) and
+      target = Resolver::resolve(this.getFolder(), newPath)
+    )
+  }
+
+  string getMainPath() { result = this.getPropStringValue(["main", "module"]) }
+
+  File getMainFile() {
+    exists(Container main | main = Resolver::resolve(this.getFolder(), this.getMainPath()) |
+      result = main
+      or
+      result = main.(Folder).getJavaScriptFileOrTypings("index")
+    )
+  }
+
+  string getAPathInFilesArray() {
+    result = this.getPropValue("files").(JsonArray).getElementStringValue(_)
+  }
+
+  Container getAFileInFilesArray() {
+    result = Resolver::resolve(this.getFolder(), this.getAPathInFilesArray())
+  }
+}
+
+private module ResolverConfig implements Folder::ResolveSig {
+  additional predicate shouldResolve(PackageJsonEx pkg, Container base, string path) {
+    base = pkg.getFolder() and
+    (
+      pkg.hasExactPathMapping(_, path)
+      or
+      pkg.hasPrefixPathMapping(_, path)
+      or
+      path = pkg.getMainPath()
+      or
+      path = pkg.getAPathInFilesArray()
+    )
+  }
+
+  predicate shouldResolve(Container base, string path) { shouldResolve(_, base, path) }
+
+  predicate getAnAdditionalChild = JSPaths::getAnAdditionalChild/2;
+
+  predicate isOptionalPathComponent(string segment) { segment = ["cjs", "mjs", "js"] }
+}
+
+private module Resolver = Folder::Resolve<ResolverConfig>;