[RFC 1/2] Add clang format file

[Stephen Hemminger <stephen@networkplumber.org>]

Based off of Linux kernel style with some local modifications
and DPDK foreach macros.

A couple of open questions to be resolved befor merging.
Is GPL license ok for config file (inherited from Linux here)?
Do we want to have per-driver files for some drivers (like MLX5)?

Signed-off-by: Stephen Hemminger <stephen@networkplumber.org>
---
 .clang-format | 181 ++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 181 insertions(+)
 create mode 100644 .clang-format

diff --git a/.clang-format b/.clang-format
new file mode 100644
index 000000000000..ad4d30520253
--- /dev/null
+++ b/.clang-format
@@ -0,0 +1,181 @@
+# SPDX-License-Identifier: GPL-2.0
+#
+# clang-format configuration file. Intended for clang-format >= 11.
+#
+# For more information, see:
+#
+#   Documentation/process/clang-format.rst
+#   https://clang.llvm.org/docs/ClangFormat.html
+#   https://clang.llvm.org/docs/ClangFormatStyleOptions.html
+#
+---
+AccessModifierOffset: -4
+AlignAfterOpenBracket: Align
+AlignConsecutiveAssignments: false
+AlignConsecutiveDeclarations: false
+AlignEscapedNewlines: Left
+AlignOperands: true
+AlignTrailingComments: false
+AllowAllParametersOfDeclarationOnNextLine: false
+AllowShortBlocksOnASingleLine: false
+AllowShortCaseLabelsOnASingleLine: false
+AllowShortFunctionsOnASingleLine: None
+AllowShortIfStatementsOnASingleLine: false
+AllowShortLoopsOnASingleLine: false
+AlwaysBreakAfterDefinitionReturnType: None
+AlwaysBreakAfterReturnType: All
+AlwaysBreakBeforeMultilineStrings: false
+BinPackArguments: true
+BinPackParameters: true
+BraceWrapping:
+  AfterClass: false
+  AfterControlStatement: false
+  AfterEnum: false
+  AfterFunction: true
+  AfterNamespace: true
+  AfterObjCDeclaration: false
+  AfterStruct: false
+  AfterUnion: false
+  AfterExternBlock: false
+  BeforeCatch: false
+  BeforeElse: false
+  IndentBraces: false
+  SplitEmptyFunction: true
+  SplitEmptyRecord: true
+  SplitEmptyNamespace: true
+BreakBeforeBinaryOperators: None
+BreakBeforeBraces: Custom
+BreakBeforeInheritanceComma: false
+BreakBeforeTernaryOperators: false
+BreakConstructorInitializersBeforeComma: false
+BreakConstructorInitializers: BeforeComma
+BreakAfterJavaFieldAnnotations: false
+BreakStringLiterals: false
+ColumnLimit: 100
+CompactNamespaces: false
+ConstructorInitializerAllOnOneLineOrOnePerLine: false
+ConstructorInitializerIndentWidth: 8
+ContinuationIndentWidth: 8
+Cpp11BracedListStyle: false
+DerivePointerAlignment: false
+DisableFormat: false
+ExperimentalAutoDetectBinPacking: false
+FixNamespaceComments: false
+
+# Taken from:
+#   git grep -h '^#define [^[:space:]]*[A-Z_]*FOREACH[A-Z_]*' lib/ drivers/ \
+#   | sed "s,^#define \([:space:]]*[A-Z_]*FOREACH[A-Z_]*\)(.*$,  - \1," \
+#   | LC_ALL=C sort -u
+ForEachMacros:
+  - CIRBUF_FOREACH
+  - FOREACH_ABS_FUNC_IN_PORT
+  - FOREACH_DEVICE_ON_AUXILARY_BUS
+  - FOREACH_DEVICE_ON_PCIBUS
+  - FOREACH_DEVICE_ON_PLATFORM_BUS
+  - FOREACH_DEVICE_ON_VMBUS
+  - FOREACH_DRIVER_ON_AUXILARY_BUS
+  - FOREACH_DRIVER_ON_PCIBUS
+  - FOREACH_DRIVER_ON_PLATFORM_BUS
+  - FOREACH_DRIVER_ON_VMBUS
+  - FOREACH_SUBDEV
+  - FOREACH_SUBDEV_STATE
+  - ILIST_FOREACH
+  - LIST_FOREACH
+  - LIST_FOREACH_FROM
+  - LIST_FOREACH_FROM_SAFE
+  - LIST_FOREACH_SAFE
+  - MLX5_ETH_FOREACH_DEV
+  - MLX5_IPOOL_FOREACH
+  - MLX5_L3T_FOREACH
+  - ML_AVG_FOREACH_QP
+  - ML_AVG_RESET_FOREACH_QP
+  - ML_MAX_FOREACH_QP
+  - ML_MAX_RESET_FOREACH_QP
+  - ML_MIN_FOREACH_QP
+  - ML_MIN_RESET_FOREACH_QP
+  - PLT_TAILQ_FOREACH_SAFE
+  - RTE_BBDEV_FORWEACH
+  - RTE_DEV_FOREACH
+  - RTE_EAL_DEVARGS_FOREACH
+  - RTE_ETH_FOREACH_DEV
+  - RTE_ETH_FOREACH_DEV_OWNED_BY
+  - RTE_ETH_FOREACH_DEV_SIBLING
+  - RTE_ETH_FOREACH_MATCHING_DEV
+  - RTE_ETH_FOREACH_VALID_DEV
+  - RTE_GPU_FOREACH
+  - RTE_GPU_FOREACH_CHILD
+  - RTE_GPU_FOREACH_PARENT
+  - RTE_LCORE_FOREACH
+  - RTE_LCORE_FOREACH_WORKER
+  - RTE_TAILQ_FOREACH
+  - RTE_TAILQ_FOREACH_SAFE
+  - SILIST_FOREACH
+  - SLIST_FOREACH
+  - SLIST_FOREACH_FROM
+  - SLIST_FOREACH_FROM_SAFE
+  - SLIST_FOREACH_SAFE
+  - STAILQ_FOREACH
+  - TAILQ_FOREACH
+  - TAILQ_FOREACH_ENTRY
+  - TAILQ_FOREACH_ENTRY_SAFE
+  - TAILQ_FOREACH_FROM_SAFE
+  - TAILQ_FOREACH_SAFE
+  - json_array_foreach
+  - json_object_foreach
+  - rte_graph_foreach
+  - rte_graph_foreach_node
+  - vdev_netvsc_foreach_iface
+
+IncludeBlocks: Preserve
+IncludeCategories:
+  - Regex: '.*'
+    Priority: 1
+IncludeIsMainRegex: '(Test)?$'
+IndentCaseLabels: false
+IndentGotoLabels: false
+IndentPPDirectives: None
+IndentWidth: 8
+IndentWrappedFunctionNames: false
+JavaScriptQuotes: Leave
+JavaScriptWrapImports: true
+KeepEmptyLinesAtTheStartOfBlocks: false
+MacroBlockBegin: ''
+MacroBlockEnd: ''
+MaxEmptyLinesToKeep: 1
+NamespaceIndentation: None
+ObjCBinPackProtocolList: Auto
+ObjCBlockIndentWidth: 8
+ObjCSpaceAfterProperty: true
+ObjCSpaceBeforeProtocolList: true
+
+# Taken from git's rules
+PenaltyBreakAssignment: 10
+PenaltyBreakBeforeFirstCallParameter: 30
+PenaltyBreakComment: 10
+PenaltyBreakFirstLessLess: 0
+PenaltyBreakString: 10
+PenaltyExcessCharacter: 100
+PenaltyReturnTypeOnItsOwnLine: 60
+
+PointerAlignment: Right
+ReflowComments: false
+SortIncludes: false
+SortUsingDeclarations: false
+SpaceAfterCStyleCast: false
+SpaceAfterTemplateKeyword: true
+SpaceBeforeAssignmentOperators: true
+SpaceBeforeCtorInitializerColon: true
+SpaceBeforeInheritanceColon: true
+SpaceBeforeParens: ControlStatementsExceptForEachMacros
+SpaceBeforeRangeBasedForLoopColon: true
+SpaceInEmptyParentheses: false
+SpacesBeforeTrailingComments: 1
+SpacesInAngles: false
+SpacesInContainerLiterals: false
+SpacesInCStyleCastParentheses: false
+SpacesInParentheses: false
+SpacesInSquareBrackets: false
+Standard: Cpp03
+TabWidth: 8
+UseTab: Always
+...
-- 
2.39.2