add libpython_ui.py extending TUI mode with Python windows

Author: Magne Hov

libpython_ui.py

@@ -0,0 +1,129 @@
+import subprocess
+
+import gdb
+
+
+def highlight_python(text):
+    """
+    Pipe bytes through the highlight program to add Python syntax highlighting.
+    """
+    if getattr(highlight_python, "failed", False):
+        return text
+    result = subprocess.run(
+        ["highlight", "--syntax=python", "--out-format=ansi"],
+        stdout=subprocess.PIPE,
+        input=text,
+        check=False,
+    )
+    if result.returncode:
+        print("Failed to provide syntax highlighting for Python.")
+        print("Please install the `highlight` program.")
+        highlight_python.failed = True
+        return text
+    return result.stdout
+
+
+def register_window(name):
+    """
+    Register a TUI window and define a new layout for it.
+    """
+
+    def decorator(cls):
+        gdb.register_window_type(name, cls)
+        gdb.execute(f"tui new-layout {name} {name} 1 status 1 cmd 1")
+        return cls
+
+    return decorator
+
+
+class Window:
+    title: str | None = None
+
+    def __init__(self, tui_window):
+        self._tui_window = tui_window
+        self._tui_window.title = self.title
+        gdb.events.before_prompt.connect(self.render)
+
+    def get_lines(self):
+        raise NotImplementedError()
+
+    def render(self):
+        if not self._tui_window.is_valid():
+            return
+
+        # Truncate output
+        lines = self.get_lines()[:self._tui_window.height]
+        lines = (line[:self._tui_window.width - 1] for line in lines)
+
+        output = "\n".join(lines)
+        self._tui_window.write(output, True)
+
+    def close(self):
+        gdb.events.before_prompt.disconnect(self.render)
+
+
+@register_window("python-source")
+class PythonSourceWindow(Window):
+    title = "Python Source"
+
+    def get_lines(self):
+        python_source = gdb.execute("py-list", to_string=True).encode("utf-8")
+        return highlight_python(python_source).decode("utf-8").splitlines()
+
+
+@register_window("python-backtrace")
+class PythonBacktraceWindow(Window):
+    title = "Python Backtrace"
+
+    def get_lines(self):
+        return gdb.execute("py-bt", to_string=True).splitlines()
+
+
+@register_window("python-locals")
+class PythonLocalsWindow(Window):
+    title = "Local Python Variables"
+
+    def get_lines(self):
+        return gdb.execute("py-locals", to_string=True).splitlines()
+
+
+@register_window("python-bytecode")
+class PythonBytecodeWindow(Window):
+    title = "Python Bytecode"
+
+    def get_lines(self):
+        lines = gdb.execute("py-dis", to_string=True).splitlines()
+        total_lines = len(lines)
+        height = self._tui_window.height
+        if total_lines < height:
+            return lines
+
+        current_line = None
+        for index, line in enumerate(lines, 1):
+            if "-->" in line:
+                current_line = index
+                break
+        else:
+            return lines[:height]
+
+        first_half = height // 2
+        second_half = height - first_half
+        if current_line < first_half:
+            return lines[:height]
+        if current_line + second_half > total_lines:
+            return lines[-height:]
+        return lines[current_line - first_half : current_line + second_half]
+
+
+# Define a layout with all Python windows
+gdb.execute(
+    " ".join(
+        (
+            "tui new-layout python",
+            "python-backtrace 2",
+            "{-horizontal python-bytecode 1 python-locals 1} 2",
+            "python-source 2",
+            "status 1 cmd 1",
+        )
+    )
+)