extracted function

handlers.py

@@ -1,6 +1,7 @@
 from abc import ABC, abstractmethod
-import os, re, docker, signal
+import os, re, docker, signal, sys
 from bs4 import BeautifulSoup
+from typing import Optional
 
 USER_ID = os.getuid() # for container user
 GROUP_ID = os.getgid() 
@@ -297,3 +298,52 @@ def clean_output(output: bytes) -> str:
     cleaned_lines = merge_unapproved_licences(cleaned_lines)
 
     return "\n".join(cleaned_lines)
+
+def get_build_handler(root: str, repo: str, updates: dict, verbose: bool = False) -> Optional[BuildHandler]:
+    """
+    Get the path to the build file of a repository. The build file is either a
+    `pom.xml`, `build.gradle`, or `build.xml` file.
+
+    Args:
+        root (str): The root directory in which the repository is located.
+        repo (str): The name of the repository.
+
+    Returns:
+        str | None: The path to the repository if it is valid, `None` otherwise
+    """
+    path = os.path.join(root, repo)
+    # Check if the given path is a directory
+    if not os.path.isdir(path):
+        error_msg = f"The path {path} is not a valid directory."
+        print(error_msg, file=sys.stderr)
+        updates["error_msg"] = error_msg
+        return None
+
+    to_keep = ["pom.xml", "build.gradle"]
+    for entry in os.scandir(path):
+        if entry.is_file() and entry.name in to_keep:
+            if verbose: print(f"Found {entry.name} in {repo} root, so keeping it and returning")
+            updates["depth_of_build_file"] = 0
+            if entry.name == "build.gradle":
+                updates["build_system"] = "gradle"
+                return GradleHandler(path, entry.name, updates)
+            else:
+                updates["build_system"] = "maven"
+                return MavenHandler(path, entry.name, updates)
+    
+    # List files in the immediate subdirectories
+    for entry in os.scandir(path):
+        if entry.is_dir():
+            for sub_entry in os.scandir(entry.path):
+                if sub_entry.is_file() and sub_entry.name in to_keep:
+                    if verbose: print(f"Found {sub_entry.name} in {repo} first level, so keeping it and returning")
+                    updates["depth_of_build_file"] = 1
+                    if entry.name == "build.gradle":
+                        updates["build_system"] = "gradle"
+                        return GradleHandler(path, os.path.join(entry.name, sub_entry.name), updates)
+                    else:
+                        updates["build_system"] = "maven"
+                        return MavenHandler(path, os.path.join(entry.name, sub_entry.name), updates)
+
+    updates["error_msg"] = "No build file found"
+    return None