Fix project reopen persistence

backend/layout_files.py

@@ -0,0 +1,126 @@
+# -----------------------------------------------------------------------------
+# Description: Layout YAML file filtering, parsing, and staging helpers.
+# Inside functions: is_layout_cell_filename, parse_layout_cell_content, read_layout_cell_file, load_layout_cell_files, layout_cell_filename, write_layout_cells_to_directory
+# Developer : Qin Yue @ 2026
+# Organization : OptiHK Limited
+# -----------------------------------------------------------------------------
+import os
+import re
+
+import yaml
+
+
+LAYOUT_YAML_EXTENSIONS = (".yml", ".yaml")
+ROUTE_SIDECAR_SUFFIXES = (".routes.yml", ".routes.yaml")
+
+
+class LayoutFileError(ValueError):
+    """Raised when a saved layout YAML file cannot be used as a cell."""
+
+
+def is_layout_cell_filename(filename):
+    """Return True for user layout cell YAML files, excluding sidecars/manifests."""
+    lower = (filename or "").lower()
+    if lower == "technology.yml":
+        return False
+    if lower.endswith(ROUTE_SIDECAR_SUFFIXES):
+        return False
+    return lower.endswith(LAYOUT_YAML_EXTENSIONS)
+
+
+def is_layout_cell_document(data):
+    """Return True when parsed YAML looks like an mxPIC saved cell/project."""
+    if not isinstance(data, dict):
+        return False
+
+    kind = data.get("kind")
+    if kind and str(kind).strip().lower() != "cell":
+        return False
+
+    layout_keys = {
+        "schema_version",
+        "canvas_size",
+        "canvasSize",
+        "instances",
+        "elements",
+        "pins",
+        "ports",
+        "bundles",
+    }
+    return any(key in data for key in layout_keys)
+
+
+def parse_layout_cell_content(content, source="layout YAML"):
+    """Parse and validate saved layout YAML content."""
+    try:
+        data = yaml.safe_load(content or "") or {}
+    except yaml.YAMLError as exc:
+        raise LayoutFileError(f"{source} is not valid YAML: {exc}") from exc
+
+    if not is_layout_cell_document(data):
+        raise LayoutFileError(f"{source} is not a saved mxPIC layout cell")
+    return data
+
+
+def read_layout_cell_file(path):
+    """Read a saved layout cell file and return parsed data plus raw content."""
+    try:
+        with open(path, "r", encoding="utf-8") as file:
+            content = file.read()
+    except OSError as exc:
+        raise LayoutFileError(f"{os.path.basename(path)} could not be read: {exc}") from exc
+    return parse_layout_cell_content(content, os.path.basename(path)), content
+
+
+def load_layout_cell_files(project_dir):
+    """Load valid layout cell files from a project directory and collect warnings."""
+    cells = []
+    warnings = []
+    if not os.path.isdir(project_dir):
+        return cells, warnings
+
+    for filename in sorted(os.listdir(project_dir)):
+        if not is_layout_cell_filename(filename):
+            continue
+        path = os.path.join(project_dir, filename)
+        if not os.path.isfile(path):
+            continue
+        try:
+            data, content = read_layout_cell_file(path)
+        except LayoutFileError as exc:
+            warnings.append(f"Skipped {filename}: {exc}")
+            continue
+
+        cells.append({
+            "filename": filename,
+            "name": str(data.get("name") or os.path.splitext(filename)[0]),
+            "data": data,
+            "content": content,
+        })
+    return cells, warnings
+
+
+def layout_cell_filename(cell_name, fallback="canvas_1.yml"):
+    """Build a safe filename for staging a parsed layout cell."""
+    name = re.sub(r"[^A-Za-z0-9_.-]+", "_", str(cell_name or "")).strip("._")
+    if not name:
+        return fallback
+    return f"{name}.yml"
+
+
+def write_layout_cells_to_directory(cells, output_dir):
+    """Write valid layout cell contents into a clean staging directory."""
+    os.makedirs(output_dir, exist_ok=True)
+    used_names = set()
+    for index, cell in enumerate(cells, start=1):
+        filename = layout_cell_filename(cell.get("name"), cell.get("filename") or f"cell_{index}.yml")
+        base, ext = os.path.splitext(filename)
+        unique_filename = filename
+        counter = 1
+        while unique_filename.lower() in used_names:
+            counter += 1
+            unique_filename = f"{base}_{counter}{ext}"
+        used_names.add(unique_filename.lower())
+
+        with open(os.path.join(output_dir, unique_filename), "w", encoding="utf-8") as file:
+            file.write(cell["content"])