From 2c3043c633b86d061e15a746ffbe41c5bc3d4d4b Mon Sep 17 00:00:00 2001
From: Andrew Hamilton <and_hamilton@yahoo.com>
Date: Wed, 15 Dec 2021 00:07:59 +1000
Subject: [PATCH] Allow custom config files.

- Needed to switch from a timestamp to a checksum.
- Added a --config command line option.
---
 eris/eris/__main__.py       | 46 ++++++++++++++++++++++++++++---------
 eris/eris/tools.py          |  9 ++++++--
 eris/tests/__main___test.py |  4 +++-
 3 files changed, 45 insertions(+), 14 deletions(-)

diff --git a/eris/eris/__main__.py b/eris/eris/__main__.py
index 618e1d8..2426b40 100755
--- a/eris/eris/__main__.py
+++ b/eris/eris/__main__.py
@@ -18,6 +18,7 @@ import asyncio
 import contextlib
 import functools
 import gzip
+import hashlib
 import importlib
 import importlib.resources
 import itertools
@@ -39,7 +40,6 @@ import pyinotify
 import termstr
 
 import eris
-import eris.tools as tools
 import eris.worker as worker
 import eris.paged_list as paged_list
 import sorted_collection
@@ -65,6 +65,7 @@ Options:
                                    highlighting. Defaults to "native".
   -c TYPE, --compression=TYPE      The type of compression used in the cache:
                                    gzip, lzma, bz2, or none. Defaults to gzip.
+  --config=FILE_NAME               Use a custom config file instead of tools.toml.
 """
 
 
@@ -1068,21 +1069,36 @@ def chdir(path):
         os.chdir(old_cwd)
 
 
+def source_checksum():
+    resources = ["__main__.py", "tools.py"]
+    if "config" not in os.environ:
+        resources.append("tools.toml")
+    checksum_paths = []
+    for resource in resources:
+        with importlib.resources.path(eris, resource) as resource_path:
+            checksum_paths.append(resource_path)
+    if "config" in os.environ:
+        checksum_paths.append(os.environ["config"])
+    sha256 = hashlib.sha256()
+    for path in checksum_paths:
+        with open(path, "rb") as source_file:
+            sha256.update(source_file.read())
+    return sha256.hexdigest()
+
+
 def manage_cache(root_path):
     cache_path = os.path.join(root_path, tools.CACHE_PATH)
-    timestamp_path = os.path.join(cache_path, "creation_time")
+    checksum_path = os.path.join(cache_path, "source_checksum")
     if os.path.exists(cache_path):
-        timestamp = os.stat(timestamp_path).st_mtime
-        for resource_path in ["__main__.py", "tools.py", "tools.toml"]:
-            with importlib.resources.path(eris, resource_path) as resource:
-                if resource.stat().st_mtime > timestamp:
-                    print("Eris has been updated, so clearing the cache and"
-                          " recalculating all results…")
-                    shutil.rmtree(cache_path)
-                    break
+        with open(checksum_path, "r") as checksum_file:
+            cache_checksum = checksum_file.read()
+        if source_checksum() != cache_checksum:
+            print("Eris has been changed, so clearing the cache and recalculating all results…")
+            shutil.rmtree(cache_path)
     if not os.path.exists(cache_path):
         os.mkdir(cache_path)
-        open(timestamp_path, "w").close()
+        with open(checksum_path, "w") as checksum_file:
+            checksum_file.write(source_checksum())
 
 
 def print_tool_info():
@@ -1105,11 +1121,19 @@ def print_tool_info():
 
 
 def check_arguments():
+    global tools
     cmdline_help = __doc__ + USAGE.replace("*", "")
     arguments = docopt.docopt(cmdline_help, help=False)
     if arguments["--help"]:
         print(cmdline_help)
         sys.exit(0)
+    if arguments["--config"] is not None:
+        config_path = arguments["--config"]
+        if not os.path.exists(config_path):
+            print("File does not exist:", config_path)
+            sys.exit(1)
+        os.environ["ERIS_CONFIG"] = config_path
+    import eris.tools as tools
     if arguments["--info"]:
         print_tool_info()
         sys.exit(0)
diff --git a/eris/eris/tools.py b/eris/eris/tools.py
index d9424df..38f79ab 100755
--- a/eris/eris/tools.py
+++ b/eris/eris/tools.py
@@ -460,8 +460,13 @@ def make_tool_function(dependencies, command, url=None, error_status=None,
 
 
 elinks, git_diff, git_blame = None, None, None  # For linters.
-with importlib.resources.open_text(eris, "tools.toml") as tools_toml_file:
-    tools_toml = toml.load(tools_toml_file)
+
+
+if "ERIS_CONFIG" in os.environ:
+    tools_toml = toml.load(os.environ["ERIS_CONFIG"])
+else:
+    with importlib.resources.open_text(eris, "tools.toml") as tools_toml_file:
+        tools_toml = toml.load(tools_toml_file)
 tools_for_extensions = tools_toml["tools_for_extensions"]
 del tools_toml["tools_for_extensions"]
 for tool_name, tool_toml in tools_toml.items():
diff --git a/eris/tests/__main___test.py b/eris/tests/__main___test.py
index e1e8e94..5643dee 100755
--- a/eris/tests/__main___test.py
+++ b/eris/tests/__main___test.py
@@ -13,6 +13,8 @@ import fill3
 
 import golden
 import eris.__main__ as __main__
+import eris.tools as tools
+__main__.tools = tools
 
 
 os.environ["TERM"] = "xterm-256color"
@@ -204,7 +206,7 @@ class MainTestCase(unittest.TestCase):
                 with contextlib.redirect_stdout(io.StringIO()):
                     loop.run_until_complete(__main__.main("test",
                         root_path, worker_count=2, is_being_tested=True))
-                for file_name in ["summary.pickle", "creation_time",
+                for file_name in ["summary.pickle", "source_checksum",
                                   "foo-metadata", "foo-contents"]:
                     self.assertTrue(os.path.exists(".eris/" + file_name))
             self.assertEqual(_mount_total(), mount_total)