Add compiledb, help and custom.py support

.gitignore

@@ -6,6 +6,12 @@ demo/bin/*
 !demo/bin/*.gdextension
 .sconsign*.dblite
 
+# Ignore custom.py
+custom.py
+
+# Ignore generated compile_commands.json
+compile_commands.json
+
 # Binaries
 *.o
 *.os

SConstruct

@@ -1,8 +1,53 @@
 #!/usr/bin/env python
+import os
+
+
+def normalize_path(val, env):
+    return val if os.path.isabs(val) else os.path.join(env.Dir("#").abspath, val)
+
+
+def validate_parent_dir(key, val, env):
+    if not os.path.isdir(normalize_path(os.path.dirname(val), env)):
+        raise UserError("'%s' is not a directory: %s" % (key, os.path.dirname(val)))
+
 
 libname = "EXTENSION-NAME"
 
-env = SConscript("godot-cpp/SConstruct")
+localEnv = Environment(tools=["default"], PLATFORM="")
+
+customs = ["custom.py"]
+customs = [os.path.abspath(path) for path in customs]
+
+opts = Variables(customs, ARGUMENTS)
+opts.Add(
+    BoolVariable(
+        key="compiledb",
+        help="Generate compilation DB (`compile_commands.json`) for external tools",
+        default=localEnv.get("compiledb", False),
+    )
+)
+opts.Add(
+    PathVariable(
+        key="compiledb_file",
+        help="Path to a custom `compile_commands.json` file",
+        default=localEnv.get("compiledb_file", "compile_commands.json"),
+        validator=validate_parent_dir,
+    )
+)
+opts.Update(localEnv)
+
+Help(opts.GenerateHelpText(localEnv))
+
+env = localEnv.Clone()
+env["compiledb"] = False
+
+env.Tool("compilation_db")
+compilation_db = env.CompilationDatabase(
+    normalize_path(localEnv["compiledb_file"], localEnv)
+)
+env.Alias("compiledb", compilation_db)
+
+env = SConscript("godot-cpp/SConstruct", {"env": env, "customs": customs})
 
 env.Append(CPPPATH=["src/"])
 sources = Glob("src/*.cpp")
@@ -19,4 +64,7 @@ else:
         source=sources,
     )
 
-Default(library)
+default_args = [library]
+if localEnv.get("compiledb", False):
+    default_args += [compilation_db]
+Default(*default_args)