resolve foreign imports in QualifiedNameResolver; simplified PyImportResolver API

python/psi-api/src/com/jetbrains/python/psi/impl/PyImportResolver.java

@@ -2,8 +2,7 @@ package com.jetbrains.python.psi.impl;
 
 import com.intellij.openapi.extensions.ExtensionPointName;
 import com.intellij.psi.PsiElement;
-import com.jetbrains.python.psi.PyElement;
-import org.jetbrains.annotations.NotNull;
+import com.jetbrains.python.psi.resolve.QualifiedNameResolveContext;
 import org.jetbrains.annotations.Nullable;
 
 /**
@@ -13,6 +12,5 @@ public interface PyImportResolver {
   ExtensionPointName<PyImportResolver> EP_NAME = ExtensionPointName.create("Pythonid.importResolver");
 
   @Nullable
-  PsiElement resolveImportReference(@NotNull PyElement importElement, @NotNull PyQualifiedName importText,
-                                    @Nullable PyQualifiedName importFrom);
+  PsiElement resolveImportReference(PyQualifiedName name, QualifiedNameResolveContext context);
 }

python/psi-api/src/com/jetbrains/python/psi/impl/PyQualifiedName.java

@@ -58,6 +58,13 @@ public class PyQualifiedName {
     return result;
   }
 
+  public PyQualifiedName append(PyQualifiedName qName) {
+    PyQualifiedName result = new PyQualifiedName(myComponents.size()+qName.getComponentCount());
+    result.myComponents.addAll(myComponents);
+    result.myComponents.addAll(result.getComponents());
+    return result;
+  }
+
   @NotNull
   public PyQualifiedName removeLastComponent() {
     return removeTail(1);
@@ -74,6 +81,17 @@ public class PyQualifiedName {
     return result;
   }
 
+  @NotNull
+  public PyQualifiedName removeHead(int count) {
+    int size = myComponents.size();
+    PyQualifiedName result = new PyQualifiedName(size);
+    result.myComponents.addAll(myComponents);
+    for (int i = 0; i < count && result.myComponents.size() > 0; i++) {
+      result.myComponents.remove(0);
+    }
+    return result;
+  }
+
   @NotNull
   public List<String> getComponents() {
     return myComponents;

python/psi-api/src/com/jetbrains/python/psi/resolve/QualifiedNameResolveContext.java

@@ -65,6 +65,7 @@ public class QualifiedNameResolveContext {
     return true;
   }
 
+  @Nullable
   public PsiFile getFootholdFile() {
     return myFootholdFile;
   }
@@ -74,6 +75,7 @@ public class QualifiedNameResolveContext {
     return myPsiManager;
   }
 
+  @NotNull
   public Project getProject() {
     return myPsiManager.getProject();
   }

python/psi-api/src/com/jetbrains/python/psi/resolve/QualifiedNameResolver.java

@@ -42,4 +42,6 @@ public interface QualifiedNameResolver {
   <T extends PsiElement> T firstResultOfType(Class<T> clazz);
 
   QualifiedNameResolver withContext(QualifiedNameResolveContext context);
+
+  QualifiedNameResolver withoutForeign();
 }