Libguestfs - Apr 2016 - [PATCH v2 FOR DISCUSSION ONLY 1/2] scripts: Add a script for formatting all C code in the project.

See previous version:
https://www.redhat.com/archives/libguestfs/2016-April/msg00021.html

The formatting in this second version isn't too bad.  Still
a few corner cases to sort out.

Rich.

Note this requires clang-format from clang >= 3.8.0
(3.7.0 is too old as it does not have the BreakBeforeBraces: Custom
style).
---
 .gitignore             |   1 +
 scripts/code-format.pl | 193 +++++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 194 insertions(+)
 create mode 100755 scripts/code-format.pl

diff --git a/.gitignore b/.gitignore
index ca4e89c..ad166d2 100644
--- a/.gitignore
+++ b/.gitignore
@@ -32,6 +32,7 @@ cscope.out
 Makefile
 Makefile.in
 
+/.clang-format
 /.sc-*
 /ABOUT-NLS
 /aclocal.m4
diff --git a/scripts/code-format.pl b/scripts/code-format.pl
new file mode 100755
index 0000000..58d3a78
--- /dev/null
+++ b/scripts/code-format.pl
@@ -0,0 +1,193 @@
+#!/usr/bin/perl -w
+# libguestfs
+# Copyright (C) 2016 Red Hat Inc.
+#
+# This program is free software; you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation; either version 2 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program; if not, write to the Free Software
+# Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+
+# Reformat the code in libguestfs (currently only C code).
+
+use warnings;
+use strict;
+
+use YAML qw(DumpFile);
+
+# Check we are run from the top level directory.
+die "$0: you must run this script from the top level source
directory\n"
+    unless -f "BUGS";
+
+# Make sure we have the clang-format program.
+system ("clang-format --help >/dev/null 2>&1") == 0
+    or die "$0: 'clang-format' program (from Clang) must be
installed\n";
+
+# Which files to process.  Use ./scripts/code-format.pl to process all
+# files in the project, else select which files to process on the
+# command line.
+
+my @files;
+if (0 == @ARGV) {
+    @files = `git ls-files '*.[ch]'`;
+    chomp @files;
+} else {
+    @files = @ARGV;
+}
+
+# http://clang.llvm.org/docs/ClangFormatStyleOptions.html
+my $clang_stylesheet = {
+    Language => "Cpp",
+    AccessModifierOffset => -2,
+    AlignAfterOpenBracket => "true",
+    AlignConsecutiveAssignments => "false",
+    AlignEscapedNewlinesLeft => "true",
+    AlignOperands => "true",
+    AlignTrailingComments => "true",
+    AllowAllParametersOfDeclarationOnNextLine => "true",
+    AllowShortBlocksOnASingleLine => "false",
+    AllowShortCaseLabelsOnASingleLine => "false",
+    AllowShortFunctionsOnASingleLine => "All",
+    AllowShortIfStatementsOnASingleLine => "false",
+    AllowShortLoopsOnASingleLine => "false",
+    AlwaysBreakAfterDefinitionReturnType => "TopLevel",
+    AlwaysBreakBeforeMultilineStrings => "false",
+    AlwaysBreakTemplateDeclarations => "false",
+    BinPackArguments => "true",
+    BinPackParameters => "true",
+    BraceWrapping => {
+        AfterClass => "false",
+        AfterControlStatement => "false",
+        AfterEnum => "false",
+        AfterFunction => "true",
+        AfterNamespace => "true",
+        AfterObjCDeclaration => "false",
+        AfterStruct => "false",
+        AfterUnion => "true",
+        BeforeCatch => "false",
+        BeforeElse => "true",
+        #AfterIndentBraces => "false",  -- only in clang >
3.8.0
+    },
+    BreakBeforeBinaryOperators => "None",
+    BreakBeforeBraces => "Custom",
+    BreakBeforeTernaryOperators => "true",
+    BreakConstructorInitializersBeforeComma => "false",
+    #BreakStringLiterals => "false",  -- only in clang > 3.8.0
+    ColumnLimit => 76,
+    CommentPragmas => "51 Franklin Street",
+    ConstructorInitializerAllOnOneLineOrOnePerLine => "false",
+    ConstructorInitializerIndentWidth => 2,
+    ContinuationIndentWidth => 2,
+    Cpp11BracedListStyle => "false",
+    DerivePointerAlignment => "false",
+    DisableFormat => "false",
+    ExperimentalAutoDetectBinPacking => "false",
+    ForEachMacros => [],
+    IndentCaseLabels => "false",
+    IndentWidth => 2,
+    IndentWrappedFunctionNames => "false",
+    KeepEmptyLinesAtTheStartOfBlocks => "true",
+    MacroBlockBegin => "",
+    MacroBlockEnd => "",
+    MaxEmptyLinesToKeep => 1,
+    NamespaceIndentation => "None",
+    ObjCBlockIndentWidth => 2,
+    ObjCSpaceAfterProperty => "false",
+    ObjCSpaceBeforeProtocolList => "true",
+    PenaltyBreakBeforeFirstCallParameter => 19,
+    PenaltyBreakComment => 300,
+    PenaltyBreakFirstLessLess => 120,
+    PenaltyBreakString => 1000,
+    PenaltyExcessCharacter => 1000000,
+    PenaltyReturnTypeOnItsOwnLine => 60,
+    PointerAlignment => "Right",
+    SortIncludes => "false",
+    SpaceAfterCStyleCast => "false",
+    SpaceBeforeAssignmentOperators => "true",
+    SpaceBeforeParens => "Always",
+    SpaceInEmptyParentheses => "false",
+    SpacesBeforeTrailingComments => 1,
+    SpacesInAngles => "false",
+    SpacesInContainerLiterals => "true",
+    SpacesInCStyleCastParentheses => "false",
+    SpacesInParentheses => "false",
+    SpacesInSquareBrackets => "false",
+    Standard => "Cpp11",
+    TabWidth => 8,
+    UseTab => "Never",
+};
+DumpFile (".clang-format", $clang_stylesheet);
+
+# Run clang-format on each file, then post-process the output further.
+foreach my $input (@files) {
+    my @o = ();
+
+    open INPUT, "clang-format $input |"
+        or die "clang-format: $input: $!";
+    push @o, $_ while <INPUT>;
+    close INPUT or die;
+
+    # Post-process the output.
+    my ($i, $j);
+    for ($i = 0; $i < @o; ++$i) {
+        # clang-format puts a space after every function, but we
+        # don't want one after the _ (gettext) function:
+        if (($o[$i] =~ s{_ \("}{_("}g) == 1) {
+            # If the following lines are strings, assume a continuation
+            # string and reduce its indent by 1 character.
+            for ($j = $i+1; $j < @o; ++$j) {
+                last if ($o[$j] =~ s{^(\s+)\s"}{$1"}) == 0;
+            }
+        }
+
+        # As above, for __attribute__:
+        $o[$i] =~ s{__attribute__\s+}{__attribute__}g;
+
+        # clang-format doesn't format __attribute__((noreturn)) on
+        # function decls correctly.
+        $o[$i] =~ s{(void\s+__attribute__\(\(noreturn\)\))\s+}{$1\n};
+
+        # If we have #define PREFIX_... on several adjacent lines,
+        # align the right hand side.  clang-format has a setting
+        # AlignConsecutiveAssignments but it invasively applies
+        # to every assignment in the code.
+        # XXX This doesn't align comments properly.
+        my $def = qr/^#define (([A-Z90-9]+)_[A-Z0-9_]+)\s(?=\S)/;
+        if ($o[$i] =~ /$def/) {
+            my $maxlen = length $1;
+            my $prefix = $2;
+            my $nr_lines = 1;
+            my $len;
+            my $spaces;
+
+            for ($j = $i+1; $j < @o; ++$j) {
+                last unless $o[$j] =~ /$def/;
+                last unless $prefix eq $2;
+                $nr_lines++;
+                $len = length $1;
+                $maxlen = $len if $maxlen < $len;
+            }
+            if ($nr_lines > 1) { # only if multiple #define PREFIX_ found
+                for (; $nr_lines >= 1; $nr_lines--, $i++) {
+                    die unless $o[$i] =~ /$def/;
+                    $len = length $1;
+                    $spaces = ' ' x ($maxlen - $len + 1);
+                    $o[$i] =~ s/$def/#define $1$spaces/;
+                }
+            }
+        }
+    }
+
+    # Overwrite the original file with the output.
+    open OUTPUT, "> $input" or die "$input: $!";
+    print OUTPUT $_ foreach @o;
+    close OUTPUT;
+}
-- 
2.7.4

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On Tue, Apr 05, 2016 at 10:56:27AM +0100, Richard W.M. Jones
wrote:
> See previous version:
> https://www.redhat.com/archives/libguestfs/2016-April/msg00021.html
> 
> The formatting in this second version isn't too bad.  Still
> a few corner cases to sort out.
I've pushed this to my private fork here:

https://github.com/rwmjones/libguestfs/tree/code-format

Rich.

-- 
Richard Jones, Virtualization Group, Red Hat http://people.redhat.com/~rjones
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