Add pre-commit config (#69)

* Add .pre-commit-config.yaml
* format all using pre-commit clang-format hook
* Add pre-commit to inject unreal header comment
* Remove prepare_commit.bat & update CODING.md
* Remove check-added-large-files, add headers before clang-format

10 files changed, 46 insertions, 148 deletions

diff --git a/.pre-commit-config.yaml b/.pre-commit-config.yaml
new file mode 100644
index 000000000..98535dd94
--- /dev/null
+++ b/.pre-commit-config.yaml
@@ -0,0 +1,28 @@
+# See https://pre-commit.com for more information
+# See https://pre-commit.com/hooks.html for more hooks
+repos:
+-   repo: https://github.com/pre-commit/pre-commit-hooks
+    rev: v3.2.0
+    hooks:
+    #-   id: end-of-file-fixer
+    #-   id: trailing-whitespace
+    #-   id: check-added-large-files
+    -   id: mixed-line-ending
+    -   id: check-yaml
+    -   id: check-case-conflict
+-   repo: https://github.com/Lucas-C/pre-commit-hooks
+    rev: v1.1.13
+    hooks:
+    -   id: insert-license
+        exclude: sha1\.(cpp|h)$
+        files: \.(cpp|h)$
+        args:
+        - --license-filepath
+        - .unreal-header  # defaults to: LICENSE.txt
+        - --comment-style
+        - //              # defaults to: #
+-   repo: https://github.com/pre-commit/mirrors-clang-format
+    rev: v13.0.1
+    hooks:
+    -   id: clang-format
+exclude: ^thirdparty/
diff --git a/.unreal-header b/.unreal-header
new file mode 100644
index 000000000..473471916
--- /dev/null
+++ b/.unreal-header
@@ -0,0 +1 @@
+Copyright Epic Games, Inc. All Rights Reserved.
\ No newline at end of file
diff --git a/CODING.md b/CODING.md
index d94d9d665..54774590f 100644
--- a/CODING.md
+++ b/CODING.md
@@ -12,4 +12,8 @@ Those who are familiar with the UE coding standards will note that we do not req
 
 To ensure consistent formatting we rely on `clang-format` to automatically format source code. This leads to consistent formatting which should lead to less surprises and more straightforward merging.
 
-Formatting is triggered via `prepare_commit` which should be used ahead of commit. We do not currently reject commits which have not been formatted, but we probably should at some point in the future.
+Formatting is ensured by using [pre-commit](https://pre-commit.com/)
+- [Install pre-commit](https://pre-commit.com/#installation) so it is available in PATH
+- Run pre-commit manually on staged files `pre-commit run`
+- Run pre-commit manually on all files `pre-commit run --all-files`
+- Install git commit hooks `pre-commit install`, which will automatically run before every commit.
diff --git a/prepare_commit.bat b/prepare_commit.bat
deleted file mode 100644
index 8e621c96c..000000000
--- a/prepare_commit.bat
+++ /dev/null
@@ -1 +0,0 @@
-python %~dp0scripts\formatcode.py %*
diff --git a/scripts/formatcode.py b/scripts/formatcode.py
deleted file mode 100644
index 49a8753da..000000000
--- a/scripts/formatcode.py
+++ /dev/null
@@ -1,138 +0,0 @@
-import argparse
-import fileinput
-import os
-import pathlib
-import re
-import subprocess
-
-match_expressions = []
-valid_extensions = []
-root_dir = ''
-use_batching = True
-
-def is_header_missing(f):
-    with open(f) as reader:
-        lines = reader.read().lstrip().splitlines()
-        if len(lines) > 0: return not lines[0].startswith("// ")
-        return True
-
-def add_headers(files, header):
-    for line in fileinput.input(files, inplace=True):
-        if fileinput.isfirstline():
-            [ print(h) for h in header.splitlines() ]
-        print(line, end="")
-
-def scan_tree(root):
-    files = []
-    header_files = []
-    with os.scandir(root) as dirs:
-        for entry in dirs:
-            if entry.is_dir():
-                scan_tree(os.path.join(root, entry.name))
-                continue
-            full_path = os.path.join(root, entry.name)
-            relative_root_path = os.path.relpath(full_path, start=root_dir)
-            if is_matching_filename(relative_root_path):
-                print("... formatting: {}".format(relative_root_path))
-                files.append(full_path)
-                if is_header_missing(full_path):
-                    header_files.append(full_path)
-    args = ""
-    if files:
-        if use_batching:
-            os.system("clang-format -i " + " ".join(files))
-        else:
-            for file in files:
-                os.system("clang-format -i " + file)
-    if header_files:
-        add_headers(header_files, "// Copyright Epic Games, Inc. All Rights Reserved.\n\n")
-
-def scan_zen(root):
-    with os.scandir(root) as dirs:
-        for entry in dirs:
-            if entry.is_dir() and entry.name.startswith("zen"):
-                    scan_tree(os.path.join(root, entry.name))
-
-def is_matching_filename(relative_root_path):
-    global match_expressions
-    global root_dir
-    global valid_extensions
-
-    if os.path.splitext(relative_root_path)[1].lower() not in valid_extensions:
-        return False
-    if not match_expressions:
-        return True
-    relative_root_path = relative_root_path.replace('\\', '/')
-    for regex in match_expressions:
-        if regex.fullmatch(relative_root_path):
-            return True
-    return False
-
-def parse_match_expressions(wildcards, matches):
-    global match_expressions
-    global valid_extensions
-
-    valid_extensions = ['.cpp', '.h']
-
-    for wildcard in wildcards:
-        regex = wildcard.replace('*', '%FORMAT_STAR%').replace('\\', '/')
-        regex = re.escape(regex)
-        regex = '.*' + regex.replace('%FORMAT_STAR%', '.*') + '.*'
-        try:
-            match_expressions.append(re.compile(regex, re.IGNORECASE))
-        except Exception as ex:
-            print(f'Could not parse input filename expression \'{wildcard}\': {str(ex)}')
-            quit()
-    for regex in matches:
-        try:
-            match_expressions.append(re.compile(regex, re.IGNORECASE))
-        except Exception as ex:
-            print(f'Could not parse input --match expression \'{regex}\': {str(ex)}')
-            quit()
-
-def validate_clang_format():
-    vstring = subprocess.check_output("clang-format --version", shell=True).decode().rstrip()
-
-    match = re.search(r'(\d+)\.(\d+)(\.(\d+))?$', vstring)
-    if not match:
-        raise ValueError("invalid version number '%s'" % vstring)
-
-    (major, minor, patch) = match.group(1, 2, 4)
-
-    if int(major) < 13:
-        if int(minor) == 0:
-            if int(patch) < 1:
-                raise ValueError(f'invalid clang-format version -- we require at least v12.0.1')
-
-def _main():
-    global root_dir, use_batching
-
-    parser = argparse.ArgumentParser()
-    parser.add_argument('filenames', nargs='*', help="Match text for filenames. If fullpath contains text it is a match, " +\
-        "* is a wildcard. Directory separators are matched by either / or \\. Case insensitive.")
-    parser.add_argument('--match', action='append', default=[], help="Match regular expression for filenames. " +\
-        "Relative path from the root zen directory must be a complete match. Directory separators are matched only by /. Case insensitive.")
-    parser.add_argument('--batch', dest='use_batching', action='store_true', help="Enable batching calls to clang-format.")
-    parser.add_argument('--no-batch', dest='use_batching', action='store_false', help="Disable batching calls to clang-format.")
-    parser.set_defaults(use_batching=True)
-    options = parser.parse_args()
-
-    parse_match_expressions(options.filenames, options.match)
-    root_dir = pathlib.Path(__file__).parent.parent.resolve()
-    use_batching = options.use_batching
-
-    validate_clang_format()
-
-    while True:
-        if (os.path.isfile(".clang-format")):
-            scan_zen(".")
-            quit()
-        else:
-            cwd = os.getcwd()
-            if os.path.dirname(cwd) == cwd:
-                quit()
-            os.chdir("..")
-
-
-if __name__ == '__main__':
-    _main()
\ No newline at end of file
diff --git a/zen/zen.cpp b/zen/zen.cpp
index 7f547a77a..dc9be5d15 100644
--- a/zen/zen.cpp
+++ b/zen/zen.cpp
@@ -1,3 +1,5 @@
+// Copyright Epic Games, Inc. All Rights Reserved.
+
 // Zen command line client utility
 //
 
diff --git a/zencore-test/zencore-test.cpp b/zencore-test/zencore-test.cpp
index cd4ce3e0a..7d7365c54 100644
--- a/zencore-test/zencore-test.cpp
+++ b/zencore-test/zencore-test.cpp
@@ -1,3 +1,5 @@
+// Copyright Epic Games, Inc. All Rights Reserved.
+
 // zencore-test.cpp : Defines the entry point for the console application.
 //
 
diff --git a/zenserver/compute/function.cpp b/zenserver/compute/function.cpp
index 996573573..7c5f33e78 100644
--- a/zenserver/compute/function.cpp
+++ b/zenserver/compute/function.cpp
@@ -485,8 +485,8 @@ HttpFunctionService::ExecActionUpstream(const WorkerDesc& Worker, CbObject& Obje
 HttpResponseCode
 HttpFunctionService::ExecActionUpstreamResult(const IoHash& WorkerId, CbObject& Object)
 {
-	const static IoHash Empty = CbObject().GetHash();
-	auto Status = m_UpstreamApply->GetStatus(WorkerId, Empty);
+	const static IoHash Empty  = CbObject().GetHash();
+	auto				Status = m_UpstreamApply->GetStatus(WorkerId, Empty);
 	if (!Status.Success)
 	{
 		return HttpResponseCode::NotFound;
diff --git a/zenserver/testing/launch.cpp b/zenserver/testing/launch.cpp
index 0334429b0..1236e6adb 100644
--- a/zenserver/testing/launch.cpp
+++ b/zenserver/testing/launch.cpp
@@ -167,10 +167,10 @@ SandboxedJob::GrantNamedObjectAccess(PWSTR ObjectName, SE_OBJECT_TYPE ObjectType
 						   .grfAccessMode		 = GRANT_ACCESS,
 						   .grfInheritance		 = grfInhericance,
 						   .Trustee				 = {.pMultipleTrustee		  = nullptr,
-										.MultipleTrusteeOperation = NO_MULTIPLE_TRUSTEE,
-										.TrusteeForm			  = TRUSTEE_IS_SID,
-										.TrusteeType			  = TRUSTEE_IS_GROUP,
-										.ptstrName				  = (PWSTR)m_AppContainerSid}};
+													.MultipleTrusteeOperation = NO_MULTIPLE_TRUSTEE,
+													.TrusteeForm			  = TRUSTEE_IS_SID,
+													.TrusteeType			  = TRUSTEE_IS_GROUP,
+													.ptstrName				  = (PWSTR)m_AppContainerSid}};
 
 	PACL OldAcl = nullptr;
 
diff --git a/zenutil/zenserverprocess.cpp b/zenutil/zenserverprocess.cpp
index f49d5f6d8..3a4957b76 100644
--- a/zenutil/zenserverprocess.cpp
+++ b/zenutil/zenserverprocess.cpp
@@ -550,8 +550,8 @@ ZenServerInstance::SpawnServer(int BasePort, std::string_view AdditionalServerAr
 	const std::filesystem::path BaseDir		  = m_Env.ProgramBaseDir();
 	const std::filesystem::path Executable	  = BaseDir / "zenserver" ZEN_EXE_SUFFIX_LITERAL;
 	CreateProcOptions			CreateOptions = {
-		  .WorkingDirectory = &CurrentDirectory,
-		  .Flags			= CreationFlags,
+				  .WorkingDirectory = &CurrentDirectory,
+				  .Flags			= CreationFlags,
 	  };
 	CreateProcResult ChildPid = CreateProc(Executable, CommandLine.ToView(), CreateOptions);
 #if ZEN_PLATFORM_WINDOWS