Make the CI enforce clang-format-clean code formatting

.clang-format

@@ -0,0 +1,270 @@
+---
+Language:        Cpp
+# BasedOnStyle:  Chromium
+AccessModifierOffset: -1
+AlignAfterOpenBracket: Align
+AlignArrayOfStructures: None
+AlignConsecutiveAssignments:
+  Enabled:         false
+  AcrossEmptyLines: false
+  AcrossComments:  false
+  AlignCompound:   false
+  PadOperators:    true
+AlignConsecutiveBitFields:
+  Enabled:         false
+  AcrossEmptyLines: false
+  AcrossComments:  false
+  AlignCompound:   false
+  PadOperators:    false
+AlignConsecutiveDeclarations:
+  Enabled:         false
+  AcrossEmptyLines: false
+  AcrossComments:  false
+  AlignCompound:   false
+  PadOperators:    false
+AlignConsecutiveMacros:
+  Enabled:         false
+  AcrossEmptyLines: false
+  AcrossComments:  false
+  AlignCompound:   false
+  PadOperators:    false
+AlignConsecutiveShortCaseStatements:
+  Enabled:         false
+  AcrossEmptyLines: false
+  AcrossComments:  false
+  AlignCaseColons: false
+AlignEscapedNewlines: Left
+AlignOperands:   Align
+AlignTrailingComments:
+  Kind:            Always
+  OverEmptyLines:  0
+AllowAllArgumentsOnNextLine: true
+AllowAllParametersOfDeclarationOnNextLine: false
+AllowShortBlocksOnASingleLine: Never
+AllowShortCaseLabelsOnASingleLine: false
+AllowShortEnumsOnASingleLine: true
+AllowShortFunctionsOnASingleLine: Inline
+AllowShortIfStatementsOnASingleLine: Never
+AllowShortLambdasOnASingleLine: All
+AllowShortLoopsOnASingleLine: false
+AlwaysBreakAfterDefinitionReturnType: None
+AlwaysBreakAfterReturnType: None
+AlwaysBreakBeforeMultilineStrings: true
+AlwaysBreakTemplateDeclarations: Yes
+AttributeMacros:
+  - __capability
+BinPackArguments: true
+BinPackParameters: true
+BitFieldColonSpacing: Both
+BraceWrapping:
+  AfterCaseLabel:  false
+  AfterClass:      false
+  AfterControlStatement: Never
+  AfterEnum:       false
+  AfterExternBlock: false
+  AfterFunction:   false
+  AfterNamespace:  false
+  AfterObjCDeclaration: false
+  AfterStruct:     false
+  AfterUnion:      false
+  BeforeCatch:     false
+  BeforeElse:      false
+  BeforeLambdaBody: false
+  BeforeWhile:     false
+  IndentBraces:    false
+  SplitEmptyFunction: true
+  SplitEmptyRecord: true
+  SplitEmptyNamespace: true
+BreakAfterAttributes: Never
+BreakAfterJavaFieldAnnotations: false
+BreakArrays:     true
+BreakBeforeBinaryOperators: None
+BreakBeforeConceptDeclarations: Always
+BreakBeforeBraces: Attach
+BreakBeforeInlineASMColon: OnlyMultiline
+BreakBeforeTernaryOperators: true
+BreakConstructorInitializers: BeforeColon
+BreakInheritanceList: BeforeColon
+BreakStringLiterals: true
+ColumnLimit:     88
+CommentPragmas:  '^ IWYU pragma:'
+CompactNamespaces: false
+ConstructorInitializerIndentWidth: 4
+ContinuationIndentWidth: 4
+Cpp11BracedListStyle: true
+DerivePointerAlignment: false
+DisableFormat:   false
+EmptyLineAfterAccessModifier: Never
+EmptyLineBeforeAccessModifier: LogicalBlock
+ExperimentalAutoDetectBinPacking: false
+FixNamespaceComments: true
+ForEachMacros:
+  - foreach
+  - Q_FOREACH
+  - BOOST_FOREACH
+IfMacros:
+  - KJ_IF_MAYBE
+IncludeBlocks:   Preserve
+IncludeCategories:
+  - Regex:           '^<ext/.*\.h>'
+    Priority:        2
+    SortPriority:    0
+    CaseSensitive:   false
+  - Regex:           '^<.*\.h>'
+    Priority:        1
+    SortPriority:    0
+    CaseSensitive:   false
+  - Regex:           '^<.*'
+    Priority:        2
+    SortPriority:    0
+    CaseSensitive:   false
+  - Regex:           '.*'
+    Priority:        3
+    SortPriority:    0
+    CaseSensitive:   false
+IncludeIsMainRegex: '([-_](test|unittest))?$'
+IncludeIsMainSourceRegex: ''
+IndentAccessModifiers: false
+IndentCaseBlocks: false
+IndentCaseLabels: true
+IndentExternBlock: AfterExternBlock
+IndentGotoLabels: true
+IndentPPDirectives: None
+IndentRequiresClause: true
+IndentWidth:     4
+IndentWrappedFunctionNames: false
+InsertBraces:    false
+InsertNewlineAtEOF: false
+InsertTrailingCommas: None
+IntegerLiteralSeparator:
+  Binary:          0
+  BinaryMinDigits: 0
+  Decimal:         0
+  DecimalMinDigits: 0
+  Hex:             0
+  HexMinDigits:    0
+JavaScriptQuotes: Leave
+JavaScriptWrapImports: true
+KeepEmptyLinesAtTheStartOfBlocks: false
+KeepEmptyLinesAtEOF: false
+LambdaBodyIndentation: Signature
+LineEnding:      DeriveLF
+MacroBlockBegin: ''
+MacroBlockEnd:   ''
+MaxEmptyLinesToKeep: 1
+NamespaceIndentation: None
+ObjCBinPackProtocolList: Never
+ObjCBlockIndentWidth: 2
+ObjCBreakBeforeNestedBlockParam: true
+ObjCSpaceAfterProperty: false
+ObjCSpaceBeforeProtocolList: true
+PackConstructorInitializers: NextLine
+PenaltyBreakAssignment: 2
+PenaltyBreakBeforeFirstCallParameter: 1
+PenaltyBreakComment: 300
+PenaltyBreakFirstLessLess: 120
+PenaltyBreakOpenParenthesis: 0
+PenaltyBreakString: 1000
+PenaltyBreakTemplateDeclaration: 10
+PenaltyExcessCharacter: 1000000
+PenaltyIndentedWhitespace: 0
+PenaltyReturnTypeOnItsOwnLine: 200
+PointerAlignment: Right
+PPIndentWidth:   -1
+QualifierAlignment: Leave
+RawStringFormats:
+  - Language:        Cpp
+    Delimiters:
+      - cc
+      - CC
+      - cpp
+      - Cpp
+      - CPP
+      - 'c++'
+      - 'C++'
+    CanonicalDelimiter: ''
+    BasedOnStyle:    google
+  - Language:        TextProto
+    Delimiters:
+      - pb
+      - PB
+      - proto
+      - PROTO
+    EnclosingFunctions:
+      - EqualsProto
+      - EquivToProto
+      - PARSE_PARTIAL_TEXT_PROTO
+      - PARSE_TEST_PROTO
+      - PARSE_TEXT_PROTO
+      - ParseTextOrDie
+      - ParseTextProtoOrDie
+      - ParseTestProto
+      - ParsePartialTestProto
+    CanonicalDelimiter: pb
+    BasedOnStyle:    google
+ReferenceAlignment: Pointer
+ReflowComments:  true
+RemoveBracesLLVM: false
+RemoveParentheses: Leave
+RemoveSemicolon: false
+RequiresClausePosition: OwnLine
+RequiresExpressionIndentation: OuterScope
+SeparateDefinitionBlocks: Leave
+ShortNamespaceLines: 1
+SortIncludes:    Never
+SortJavaStaticImport: Before
+SortUsingDeclarations: LexicographicNumeric
+SpaceAfterCStyleCast: false
+SpaceAfterLogicalNot: true
+SpaceAfterTemplateKeyword: true
+SpaceAroundPointerQualifiers: Default
+SpaceBeforeAssignmentOperators: true
+SpaceBeforeCaseColon: false
+SpaceBeforeCpp11BracedList: false
+SpaceBeforeCtorInitializerColon: true
+SpaceBeforeInheritanceColon: true
+SpaceBeforeJsonColon: false
+SpaceBeforeParens: ControlStatements
+SpaceBeforeParensOptions:
+  AfterControlStatements: true
+  AfterForeachMacros: true
+  AfterFunctionDefinitionName: false
+  AfterFunctionDeclarationName: false
+  AfterIfMacros:   true
+  AfterOverloadedOperator: false
+  AfterRequiresInClause: false
+  AfterRequiresInExpression: false
+  BeforeNonEmptyParentheses: false
+SpaceBeforeRangeBasedForLoopColon: true
+SpaceBeforeSquareBrackets: false
+SpaceInEmptyBlock: false
+SpacesBeforeTrailingComments: 2
+SpacesInAngles:  Never
+SpacesInContainerLiterals: true
+SpacesInLineCommentPrefix:
+  Minimum:         1
+  Maximum:         -1
+SpacesInParens:  Never
+SpacesInParensOptions:
+  InCStyleCasts:   false
+  InConditionalStatements: false
+  InEmptyParentheses: false
+  Other:           false
+SpacesInSquareBrackets: false
+Standard:        Auto
+StatementAttributeLikeMacros:
+  - Q_EMIT
+StatementMacros:
+  - Q_UNUSED
+  - QT_REQUIRE_VERSION
+TabWidth:        8
+UseTab:          Never
+VerilogBreakBetweenInstancePorts: true
+WhitespaceSensitiveMacros:
+  - BOOST_PP_STRINGIZE
+  - CF_SWIFT_NAME
+  - NS_SWIFT_NAME
+  - PP_STRINGIZE
+  - STRINGIZE
+...
+

.github/workflows/clang_format.yml

@@ -0,0 +1,45 @@
+# Copyright (c) 2023 Sebastian Pipping <[email protected]>
+# Licensed under Apache License Version 2.0
+
+name: Enforce clang-format
+
+on:
+  pull_request:
+  push:
+  schedule:
+    - cron: '0 3 * * 5'  # Every Friday at 3am
+  workflow_dispatch:
+
+# Minimum permissions for security
+permissions:
+  contents: read
+
+jobs:
+  clang-format:
+    name: Enforce clang-format
+    runs-on: ubuntu-22.04
+    env:
+      CLANG_MAJOR_VERSION: 17
+    steps:
+      - uses: actions/checkout@b4ffde65f46336ab88eb53be808477a3936bae11  # v4.1.1
+
+      - name: Add Clang/LLVM repositories
+        run: |-
+          set -x
+          source /etc/os-release
+          wget -O - https://apt.llvm.org/llvm-snapshot.gpg.key | sudo apt-key add -
+          sudo add-apt-repository "deb http://apt.llvm.org/${UBUNTU_CODENAME}/ llvm-toolchain-${UBUNTU_CODENAME}-${CLANG_MAJOR_VERSION} main"
+
+      - name: Install clang-format
+        run: |-
+          set -x
+          sudo apt-get update
+          sudo apt-get install --yes --no-install-recommends -V \
+              clang-format-${CLANG_MAJOR_VERSION}
+
+      - name: Enforce clang-format
+        run: |-
+          set -x
+          clang-format-${CLANG_MAJOR_VERSION} --version
+          clang-format-${CLANG_MAJOR_VERSION} -i *.c
+          git diff --exit-code  # i.e. reject non-empty diff

stresstest.c

@@ -70,20 +70,23 @@ int main(int argc, char *argv[]) {
     const useconds_t delay = 1e6 / rate;
     srand(seed);
 
-    for (unsigned int n=0; ; n+=5) {
-        buffer_pos += sprintf(buffer + buffer_pos, "%.1f\n", (sin(n*M_PI/180)*5)+5);
+    for (unsigned int n = 0;; n += 5) {
+        buffer_pos +=
+            sprintf(buffer + buffer_pos, "%.1f\n", (sin(n * M_PI / 180) * 5) + 5);
         if (add_garbage && rand() <= RAND_MAX / 5)
             buffer_pos += sprintf(buffer + buffer_pos, "garbage ");
         if (two_waves) {
-            buffer_pos += sprintf(buffer + buffer_pos, "%.1f\n", (cos(n*M_PI/180)*5)+5);
+            buffer_pos +=
+                sprintf(buffer + buffer_pos, "%.1f\n", (cos(n * M_PI / 180) * 5) + 5);
             if (add_garbage && rand() <= RAND_MAX / 5)
                 buffer_pos += sprintf(buffer + buffer_pos, "garbage ");
         }
         if (chunked) {
             size_t send_pos = 0;
             while (buffer_pos - send_pos >= 16) {
                 const size_t bytes_to_send = 1 + rand() % 16;  // 1..16
-                const ssize_t bytes_sent = write(STDOUT_FILENO, buffer + send_pos, bytes_to_send);
+                const ssize_t bytes_sent =
+                    write(STDOUT_FILENO, buffer + send_pos, bytes_to_send);
                 usleep(50);  // let ttyplot read this before proceeding
                 if (bytes_sent > 0)
                     send_pos += bytes_sent;