cgitize.git: proper config writer classes

1 files changed, 99 insertions, 4 deletions

diff --git a/cgitize/git.py b/cgitize/git.py
index a2be8df..78679d7 100644
--- a/cgitize/git.py
+++ b/cgitize/git.py
@@ -39,6 +39,102 @@ class Config:
         finally:
             self.write(old_contents)
 
+    # What follows is an exteremely loose interpretation of what the .gitconfig
+    # syntax is. The source was git-config(1).
+
+    class Section:
+        def __init__(self, name, variables):
+            Config.Section.validate_name(name)
+            self.name = name
+            self.variables = variables
+
+        @staticmethod
+        def validate_name(name):
+            if not name:
+                raise RuntimeError('section names cannot be empty')
+            for c in name:
+                if c.isalnum() or c == '-' or c == '.':
+                    continue
+                raise RuntimeError(f'section names must only contain alphanumeric characters, . or -: {name}')
+
+        @staticmethod
+        def format_name(name):
+            return name
+
+        def format(self):
+            result = '[self.format_name(self.name)]\n'
+            result += ''.join((var.format() for var in self.variables))
+            return result
+
+    class Subsection:
+        def __init__(self, section, name, variables):
+            Config.Section.validate_name(section)
+            Config.Subsection.validate_name(name)
+            self.section = section
+            self.name = name
+            self.variables = variables
+
+        @staticmethod
+        def validate_name(name):
+            if '\n' in name:
+                raise RuntimeError(f'subsection names cannot contain newlines: {name}')
+
+        def format_name(self):
+            name = self.name
+            # Escape the backslashes:
+            name = name.replace('\\', '\\\\')
+            # Escape the quotes:
+            name = name.replace('"', '\\"')
+            # Put in quotes:
+            return f'"{name}"'
+
+        def format(self):
+            result = f'[{Config.Section.format_name(self.section)} {self.format_name()}]\n'
+            result += ''.join((var.format() for var in self.variables))
+            return result
+
+    class Variable:
+        def __init__(self, name, value):
+            Config.Variable.validate_name(name)
+            Config.Variable.validate_value(value)
+            self.name = name
+            self.value = value
+
+        @staticmethod
+        def validate_name(name):
+            if not name:
+                raise RuntimeError('variable names cannot be empty')
+            for c in name:
+                if c.isalnum() or c == '-':
+                    continue
+                raise RuntimeError(f'variable name can only contain alphanumeric characters or -: {name}')
+            if not name[0].isalnum():
+                raise RuntimeError(f'variable name must start with an alphanumeric character: {name}')
+
+        @staticmethod
+        def validate_value(value):
+            pass
+
+        def format_name(self):
+            return self.name
+
+        def format_value(self):
+            value = self.value
+            # Escape the backslashes:
+            value = value.replace('\\', '\\\\')
+            # Escape the supported escape sequences (\n, \t and \b):
+            value = value.replace('\n', '\\n')
+            value = value.replace('\t', '\\t')
+            value = value.replace('\b', '\\b')
+            # Escape the quotes:
+            value = value.replace('"', '\\"')
+            # Put in quotes:
+            value = f'"{value}"'
+            return value
+
+        def format(self):
+            return f'    {self.format_name()} = {self.format_value()}\n'
+
 
 class Git:
     EXE = 'git'
@@ -64,9 +160,8 @@ class Git:
         config = Git.get_global_config()
         with utils.protected_file(config.path):
             with config.backup() as old_contents:
-                new_contents = f'''{old_contents}
-[url "{repo.clone_url_with_auth}"]
-    insteadOf = {repo.clone_url}
-'''
+                variables = [Config.Variable('insteadOf', repo.clone_url)]
+                subsection = Config.Subsection('url', repo.clone_url_with_auth, variables)
+                new_contents = f'{old_contents}\n{subsection.format()}'
                 config.write(new_contents)
                 yield