Unify check_repo_path

We had 4 identical copies of the check_repo_path function. Replace them by a
single copy in the build_tree module where it naturally belongs.

Signed-off-by: Gilles Peskine <Gilles.Peskine@arm.com>
diff --git a/scripts/abi_check.py b/scripts/abi_check.py
index c228843..ac1d60f 100755
--- a/scripts/abi_check.py
+++ b/scripts/abi_check.py
@@ -113,6 +113,8 @@
 
 import xml.etree.ElementTree as ET
 
+from mbedtls_dev import build_tree
+
 
 class AbiChecker:
     """API and ABI checker."""
@@ -150,11 +152,6 @@
         self.git_command = "git"
         self.make_command = "make"
 
-    @staticmethod
-    def check_repo_path():
-        if not all(os.path.isdir(d) for d in ["include", "library", "tests"]):
-            raise Exception("Must be run from Mbed TLS root")
-
     def _setup_logger(self):
         self.log = logging.getLogger()
         if self.verbose:
@@ -540,7 +537,7 @@
     def check_for_abi_changes(self):
         """Generate a report of ABI differences
         between self.old_rev and self.new_rev."""
-        self.check_repo_path()
+        build_tree.check_repo_path()
         if self.check_api or self.check_abi:
             self.check_abi_tools_are_installed()
         self._get_abi_dump_for_ref(self.old_version)
diff --git a/scripts/code_size_compare.py b/scripts/code_size_compare.py
index 0ef438d..af6ddd4 100755
--- a/scripts/code_size_compare.py
+++ b/scripts/code_size_compare.py
@@ -30,6 +30,9 @@
 import subprocess
 import sys
 
+from mbedtls_dev import build_tree
+
+
 class CodeSizeComparison:
     """Compare code size between two Git revisions."""
 
@@ -52,11 +55,6 @@
         self.make_command = "make"
 
     @staticmethod
-    def check_repo_path():
-        if not all(os.path.isdir(d) for d in ["include", "library", "tests"]):
-            raise Exception("Must be run from Mbed TLS root")
-
-    @staticmethod
     def validate_revision(revision):
         result = subprocess.check_output(["git", "rev-parse", "--verify",
                                           revision + "^{commit}"], shell=False)
@@ -172,7 +170,7 @@
     def get_comparision_results(self):
         """Compare size of library/*.o between self.old_rev and self.new_rev,
         and generate the result file."""
-        self.check_repo_path()
+        build_tree.check_repo_path()
         self._get_code_size_for_rev(self.old_rev)
         self._get_code_size_for_rev(self.new_rev)
         return self.compare_code_size()
diff --git a/scripts/mbedtls_dev/build_tree.py b/scripts/mbedtls_dev/build_tree.py
index 3920d0e..f52b785 100644
--- a/scripts/mbedtls_dev/build_tree.py
+++ b/scripts/mbedtls_dev/build_tree.py
@@ -25,6 +25,13 @@
     return all(os.path.isdir(os.path.join(path, subdir))
                for subdir in ['include', 'library', 'programs', 'tests'])
 
+def check_repo_path():
+    """
+    Check that the current working directory is the project root, and throw
+    an exception if not.
+    """
+    if not all(os.path.isdir(d) for d in ["include", "library", "tests"]):
+        raise Exception("This script must be run from Mbed TLS root")
 
 def chdir_to_root() -> None:
     """Detect the root of the Mbed TLS source tree and change to it.
diff --git a/tests/scripts/check_files.py b/tests/scripts/check_files.py
index a0f5e1f..5c18702 100755
--- a/tests/scripts/check_files.py
+++ b/tests/scripts/check_files.py
@@ -34,6 +34,9 @@
 except ImportError:
     pass
 
+import scripts_path # pylint: disable=unused-import
+from mbedtls_dev import build_tree
+
 
 class FileIssueTracker:
     """Base class for file-wide issue tracking.
@@ -338,7 +341,7 @@
         """Instantiate the sanity checker.
         Check files under the current directory.
         Write a report of issues to log_file."""
-        self.check_repo_path()
+        build_tree.check_repo_path()
         self.logger = None
         self.setup_logger(log_file)
         self.issues_to_check = [
@@ -353,11 +356,6 @@
             MergeArtifactIssueTracker(),
         ]
 
-    @staticmethod
-    def check_repo_path():
-        if not all(os.path.isdir(d) for d in ["include", "library", "tests"]):
-            raise Exception("Must be run from Mbed TLS root")
-
     def setup_logger(self, log_file, level=logging.INFO):
         self.logger = logging.getLogger()
         self.logger.setLevel(level)
diff --git a/tests/scripts/check_names.py b/tests/scripts/check_names.py
index e204487..aece1ef 100755
--- a/tests/scripts/check_names.py
+++ b/tests/scripts/check_names.py
@@ -56,6 +56,10 @@
 import subprocess
 import logging
 
+import scripts_path # pylint: disable=unused-import
+from mbedtls_dev import build_tree
+
+
 # Naming patterns to check against. These are defined outside the NameCheck
 # class for ease of modification.
 PUBLIC_MACRO_PATTERN = r"^(MBEDTLS|PSA)_[0-9A-Z_]*[0-9A-Z]$"
@@ -219,7 +223,7 @@
     """
     def __init__(self, log):
         self.log = log
-        self.check_repo_path()
+        build_tree.check_repo_path()
 
         # Memo for storing "glob expression": set(filepaths)
         self.files = {}
@@ -228,15 +232,6 @@
         # Note that "*" can match directory separators in exclude lists.
         self.excluded_files = ["*/bn_mul", "*/compat-2.x.h"]
 
-    @staticmethod
-    def check_repo_path():
-        """
-        Check that the current working directory is the project root, and throw
-        an exception if not.
-        """
-        if not all(os.path.isdir(d) for d in ["include", "library", "tests"]):
-            raise Exception("This script must be run from Mbed TLS root")
-
     def comprehensive_parse(self):
         """
         Comprehensive ("default") function to call each parsing function and