snippets_translate: Handle connect statements

Replace pairs of instance/pointer to member functions (PMF) by
the Python dot notation and connect statements afterwards.

Task-number: PYSIDE-1721
Change-Id: I29f01d47026e3a7ab2407cf8c5b112533d5fb4dc
Reviewed-by: Christian Tismer <tismer@stackless.com>
(cherry picked from commit ed4474cb3be12c1a9566c6cd7299db39e7b9a756)
Reviewed-by: Qt Cherry-pick Bot <cherrypick_bot@qt-project.org>

3 files changed, 53 insertions, 3 deletions

diff --git a/tools/snippets_translate/converter.py b/tools/snippets_translate/converter.py
index 01df94505..77250a857 100644
--- a/tools/snippets_translate/converter.py
+++ b/tools/snippets_translate/converter.py
@@ -46,7 +46,7 @@ from handlers import (handle_array_declarations, handle_casts, handle_class,
                       handle_inc_dec, handle_include, handle_keywords,
                       handle_methods_return_type, handle_negate,
                       handle_type_var_declaration, handle_useless_qt_classes,
-                      handle_void_functions)
+                      handle_void_functions, handle_qt_connects)
 from parse_utils import dstrip, get_indent, remove_ref
 
 
@@ -76,6 +76,10 @@ def snippet_translate(x):
         x = x.replace("//", "#", 1)
         return x
 
+    qt_connects = handle_qt_connects(x)
+    if qt_connects:
+        return qt_connects
+
     # Handle "->"
     if "->" in x:
         x = x.replace("->", ".")
diff --git a/tools/snippets_translate/handlers.py b/tools/snippets_translate/handlers.py
index 40ba71841..72c70eef8 100644
--- a/tools/snippets_translate/handlers.py
+++ b/tools/snippets_translate/handlers.py
@@ -545,3 +545,49 @@ def handle_useless_qt_classes(x):
         if content:
             x = x.replace(content.group(0), content.group(1))
     return x
+
+
+# The code below handles pairs of instance/pointer to member functions (PMF)
+# which appear in Qt in connect statements like:
+# "connect(fontButton, &QAbstractButton::clicked, this, &Dialog::setFont)".
+# In a first pass, these pairs are replaced by:
+# "connect(fontButton.clicked, self.setFont)" to be able to handle statements
+# spanning lines. A 2nd pass then checks for the presence of a connect
+# statement and replaces it by:
+# "fontButton.clicked.connect(self.setFont)".
+# To be called right after checking for comments.
+
+
+INSTANCE_PMF_RE = re.compile(r"&?(\w+),\s*&\w+::(\w+)")
+
+
+CONNECT_RE = re.compile(r"^(\s*)(QObject::)?connect\((\w+\.\w+),\s*")
+
+
+def handle_qt_connects(line):
+    if not INSTANCE_PMF_RE.search(line):
+        return None
+    # 1st pass, "fontButton, &QAbstractButton::clicked" -> "fontButton.clicked"
+    last_pos = 0
+    result = ""
+    for match in INSTANCE_PMF_RE.finditer(line):
+        instance = match.group(1)
+        if instance == "this":
+            instance = "self"
+        member_fun = match.group(2)
+        next_pos = match.start()
+        result += line[last_pos:next_pos]
+        last_pos = match.end()
+        result += f"{instance}.{member_fun}"
+    result += line[last_pos:]
+
+    # 2nd pass, reorder connect.
+    connect_match = CONNECT_RE.match(result)
+    if not connect_match:
+        return result
+
+    space = connect_match.group(1)
+    signal_ = connect_match.group(3)
+    connect_stmt = f"{space}{signal_}.connect("
+    connect_stmt += result[connect_match.end():]
+    return connect_stmt
diff --git a/tools/snippets_translate/tests/test_converter.py b/tools/snippets_translate/tests/test_converter.py
index b2d6468d8..2c127a7ba 100644
--- a/tools/snippets_translate/tests/test_converter.py
+++ b/tools/snippets_translate/tests/test_converter.py
@@ -137,7 +137,7 @@ def test_double_colon():
     # multiline statement connect statement
     # eg: connect(reply, &QNetworkReply::errorOccurred,
     #    this, &MyClass::slotError);
-    assert st("this, &MyClass::slotError);") == "self, MyClass.slotError)"
+    assert st("this, &MyClass::slotError);") == "self.slotError)"
 
 
 def test_cout_endl():
@@ -411,7 +411,7 @@ def test_special_cases():
     )
     assert (
         st("QObject::connect(&window1, &Window::messageSent,")
-        == "QObject.connect(window1, Window.messageSent,"
+        == "window1.messageSent.connect("
     )
     assert st("double num;") == "num = float()"