scripts/checkpatch: introduce tracking of file start/end

Some checks want to be performed either at the start of a new file
within a patch, or at the end. This is complicated by the fact that
the information relevant to the check may be spread across multiple
lines. It is further complicated by a need to support both git and
non-git diffs, and special handling for renames where there might
not be any patch hunks.

To handle this more sanely, introduce explicit tracking of file
start/end, taking account of git metadata, and calling a hook
function at each transition.

Reviewed-by: Cédric Le Goater <clg@redhat.com>
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>

diff --git a/scripts/checkpatch.pl b/scripts/checkpatch.pl
index 2c19f6f0f251879cdefd302053e56e45e6f2b782..bb3830d693989df479cedcdad52d7f91771aa956 100755 (executable)
--- a/scripts/checkpatch.pl
+++ b/scripts/checkpatch.pl
@@ -1417,6 +1417,39 @@ sub checkspdx {
     }
 }
 
+# All three of the methods below take a 'file info' record
+# which is a hash ref containing
+#
+#  'isgit': 1 if an enhanced git diff or 0 for a plain diff
+#  'githeader': 1 if still parsing git patch header, 0 otherwise
+#  'linestart': line number of start of file diff
+#  'lineend': line number of end of file diff
+#  'filenew': the new filename
+#  'fileold': the old filename (same as 'new filename' except
+#             for renames in git diffs)
+#  'action': one of 'modified' (always) or 'new' or 'deleted' or
+#            'renamed' (git diffs only)
+#  'mode': file mode for new/deleted files (git diffs only)
+#  'similarity': file similarity when renamed (git diffs only)
+#  'facts': hash ref for storing any metadata related to checks
+#
+
+# Called at the end of each patch, with the list of
+# real filenames that were seen in the patch
+sub process_file_list {
+       my @fileinfos = @_;
+}
+
+# Called at the start of processing a diff hunk for a file
+sub process_start_of_file {
+       my $fileinfo = shift;
+}
+
+# Called at the end of processing a diff hunk for a file
+sub process_end_of_file {
+       my $fileinfo = shift;
+}
+
 sub process {
        my $filename = shift;
 
@@ -1453,7 +1486,10 @@ sub process {
        my $realfile = '';
        my $realline = 0;
        my $realcnt = 0;
+       my $fileinfo;
+       my @fileinfolist;
        my $here = '';
+       my $oldhere = '';
        my $in_comment = 0;
        my $comment_edge = 0;
        my $first_line = 0;
@@ -1591,17 +1627,56 @@ sub process {
                $prefix = "$filename:$realline: " if ($emacs && $file);
                $prefix = "$filename:$linenr: " if ($emacs && !$file);
 
+               $oldhere = $here;
                $here = "#$linenr: " if (!$file);
                $here = "#$realline: " if ($file);
 
                # extract the filename as it passes
-               if ($line =~ /^diff --git.*?(\S+)$/) {
-                       $realfile = $1;
-                       $realfile =~ s@^([^/]*)/@@ if (!$file);
+               if ($line =~ /^diff --git\s+(\S+)\s+(\S+)$/) {
+                       my $fileold = $1;
+                       my $filenew = $2;
+
+                       if (defined $fileinfo) {
+                               $fileinfo->{lineend} = $oldhere;
+                               process_end_of_file($fileinfo)
+                       }
+                       $fileold =~ s@^([^/]*)/@@ if (!$file);
+                       $filenew =~ s@^([^/]*)/@@ if (!$file);
+                       $realfile = $filenew;
                        checkfilename($realfile, \$acpi_testexpected, \$acpi_nontestexpected);
+
+                       $fileinfo = {
+                               "isgit" => 1,
+                               "githeader" => 1,
+                               "linestart" => $here,
+                               "lineend" => 0,
+                               "fileold" => $fileold,
+                               "filenew" => $filenew,
+                               "action" => "modified",
+                               "mode" => 0,
+                               "similarity" => 0,
+                               "facts" => {},
+                       };
+                       push @fileinfolist, $fileinfo;
+               } elsif (defined $fileinfo && $fileinfo->{githeader} &&
+                        $line =~ /^(new|deleted) (?:file )?mode\s+([0-7]+)$/) {
+                       $fileinfo->{action} = $1;
+                       $fileinfo->{mode} = oct($2);
+               } elsif (defined $fileinfo && $fileinfo->{githeader} &&
+                        $line =~ /^similarity index (\d+)%/) {
+                       $fileinfo->{similarity} = int($1);
+               } elsif (defined $fileinfo && $fileinfo->{githeader} &&
+                        $line =~ /^rename (from|to) [\w\/\.\-]+\s*$/) {
+                       $fileinfo->{action} = "renamed";
+                       # For a no-change rename, we'll never have any "+++..."
+                       # lines, so trigger actions now
+                       if ($1 eq "to" && $fileinfo->{similarity} == 100)  {
+                               process_start_of_file($fileinfo);
+                       }
                } elsif ($line =~ /^\+\+\+\s+(\S+)/) {
                        $realfile = $1;
                        $realfile =~ s@^([^/]*)/@@ if (!$file);
+
                        checkfilename($realfile, \$acpi_testexpected, \$acpi_nontestexpected);
 
                        $p1_prefix = $1;
@@ -1610,6 +1685,30 @@ sub process {
                                WARN("patch prefix '$p1_prefix' exists, appears to be a -p0 patch\n");
                        }
 
+                       if (defined $fileinfo && !$fileinfo->{isgit}) {
+                               $fileinfo->{lineend} = $oldhere;
+                               process_end_of_file($fileinfo);
+                       }
+
+                       if (!defined $fileinfo || !$fileinfo->{isgit}) {
+                               $fileinfo = {
+                                       "isgit" => 0,
+                                       "githeader" => 0,
+                                       "linestart" => $here,
+                                       "lineend" => 0,
+                                       "fileold" => $realfile,
+                                       "filenew" => $realfile,
+                                       "action" => "modified",
+                                       "mode" => 0,
+                                       "similarity" => 0,
+                                       "facts" => {},
+                               };
+                               push @fileinfolist, $fileinfo;
+                       } else {
+                               $fileinfo->{githeader} = 0;
+                       }
+                       process_start_of_file($fileinfo);
+
                        next;
                }
 
@@ -3216,6 +3315,11 @@ sub process {
                }
        }
 
+       if (defined $fileinfo) {
+               process_end_of_file($fileinfo);
+       }
+       process_file_list(@fileinfolist);
+
        if ($is_patch && $chk_signoff && $signoff == 0) {
                ERROR("Missing Signed-off-by: line(s)\n");
        }