Add FlattenFiles utility conversion node

meshroom/nodes/general/FlattenFiles.py

@@ -0,0 +1,59 @@
+__version__ = "1.0"
+
+from meshroom.core import desc
+
+
+class FlattenFiles(desc.Node):
+    """
+    Utility conversion node that flattens a list of lists of files into a single list of files.
+    """
+
+    category = "Utils"
+    documentation = """
+This node takes a list of lists of files as input and produces a single flat list of files as output.
+
+It is useful to merge multiple file lists coming from different nodes into a unified list,
+for example before passing them to a node that expects a flat list.
+"""
+
+    inputs = [
+        desc.ListAttribute(
+            elementDesc=desc.ListAttribute(
+                elementDesc=desc.File(
+                    name="file",
+                    label="File",
+                    description="A file.",
+                    value="",
+                ),
+                name="fileList",
+                label="File List",
+                description="A list of files.",
+            ),
+            name="inputFiles",
+            label="Input Files",
+            description="List of lists of files to flatten into a single list.",
+            exposed=True,
+        ),
+    ]
+
+    outputs = [
+        desc.ListAttribute(
+            elementDesc=desc.File(
+                name="file",
+                label="File",
+                description="A file.",
+                value="",
+            ),
+            name="outputFiles",
+            label="Output Files",
+            description="Flat list of all files from the input lists.",
+            exposed=True,
+        ),
+    ]
+
+    def process(self, node):
+        flatFiles = []
+        for fileList in node.inputFiles.value:
+            for fileAttr in fileList.value:
+                flatFiles.append(fileAttr.value)
+        node.outputFiles.value = flatFiles