diff mbox series

[2/2] xen/misra: diff-report.py: add report patching feature

Message ID 20230519094613.2134153-3-luca.fancellu@arm.com (mailing list archive)
State Superseded
Headers show
Series diff-report.py tool | expand

Commit Message

Luca Fancellu May 19, 2023, 9:46 a.m. UTC
Add a feature to the diff-report.py script that improves the comparison
between two analysis report, one from a baseline codebase and the other
from the changes applied to the baseline.

The comparison between reports of different codebase is an issue because
entries in the baseline could have been moved in position due to addition
or deletion of unrelated lines or can disappear because of deletion of
the interested line, making the comparison between two revisions of the
code harder.

Having a baseline report, a report of the codebase with the changes
called "new report" and a git diff format file that describes the
changes happened to the code from the baseline, this feature can
understand which entries from the baseline report are deleted or shifted
in position due to changes to unrelated lines and can modify them as
they will appear in the "new report".

Having the "patched baseline" and the "new report", now it's simple
to make the diff between them and print only the entry that are new.

Signed-off-by: Luca Fancellu <luca.fancellu@arm.com>
---
Changes from v1:
 - Made the script compatible with python2 (Stefano)
---
 xen/scripts/diff-report.py                    |  55 ++++-
 xen/scripts/xen_analysis/diff_tool/debug.py   |  21 ++
 xen/scripts/xen_analysis/diff_tool/report.py  |  87 +++++++
 .../diff_tool/unified_format_parser.py        | 232 ++++++++++++++++++
 4 files changed, 393 insertions(+), 2 deletions(-)
 create mode 100644 xen/scripts/xen_analysis/diff_tool/unified_format_parser.py

Comments

Luca Fancellu May 19, 2023, 10:23 a.m. UTC | #1
> On 19 May 2023, at 10:46, Luca Fancellu <Luca.Fancellu@arm.com> wrote:
> 
> Add a feature to the diff-report.py script that improves the comparison
> between two analysis report, one from a baseline codebase and the other
> from the changes applied to the baseline.
> 
> The comparison between reports of different codebase is an issue because
> entries in the baseline could have been moved in position due to addition
> or deletion of unrelated lines or can disappear because of deletion of
> the interested line, making the comparison between two revisions of the
> code harder.
> 
> Having a baseline report, a report of the codebase with the changes
> called "new report" and a git diff format file that describes the
> changes happened to the code from the baseline, this feature can
> understand which entries from the baseline report are deleted or shifted
> in position due to changes to unrelated lines and can modify them as
> they will appear in the "new report".
> 
> Having the "patched baseline" and the "new report", now it's simple
> to make the diff between them and print only the entry that are new.
> 
> Signed-off-by: Luca Fancellu <luca.fancellu@arm.com>
> ---
> Changes from v1:
> - Made the script compatible with python2 (Stefano)
> ---
> xen/scripts/diff-report.py                    |  55 ++++-
> xen/scripts/xen_analysis/diff_tool/debug.py   |  21 ++
> xen/scripts/xen_analysis/diff_tool/report.py  |  87 +++++++
> .../diff_tool/unified_format_parser.py        | 232 ++++++++++++++++++
> 4 files changed, 393 insertions(+), 2 deletions(-)
> create mode 100644 xen/scripts/xen_analysis/diff_tool/unified_format_parser.py
> 
> diff --git a/xen/scripts/diff-report.py b/xen/scripts/diff-report.py
> index f97cb2355cc3..d608e3a05aa1 100755
> --- a/xen/scripts/diff-report.py
> +++ b/xen/scripts/diff-report.py
> @@ -7,6 +7,10 @@ from argparse import ArgumentParser
> from xen_analysis.diff_tool.cppcheck_report import CppcheckReport
> from xen_analysis.diff_tool.debug import Debug
> from xen_analysis.diff_tool.report import ReportError
> +from xen_analysis.diff_tool.unified_format_parser import \
> +    (UnifiedFormatParser, UnifiedFormatParseError)
> +from xen_analysis.settings import repo_dir
> +from xen_analysis.utils import invoke_command
> 
> 
> def log_info(text, end='\n'):
> @@ -36,9 +40,32 @@ def main(argv):
>                              "against the baseline.")
>     parser.add_argument("-v", "--verbose", action='store_true',
>                         help="Print more informations during the run.")
> +    parser.add_argument("--patch", type=str,
> +                        help="The patch file containing the changes to the "
> +                             "code, from the baseline analysis result to the "
> +                             "'check report' analysis result.\n"
> +                             "Do not use with --baseline-rev/--report-rev")
> +    parser.add_argument("--baseline-rev", type=str,
> +                        help="Revision or SHA of the codebase analysed to "
> +                             "create the baseline report.\n"
> +                             "Use together with --report-rev")
> +    parser.add_argument("--report-rev", type=str,
> +                        help="Revision or SHA of the codebase analysed to "
> +                             "create the 'check report'.\n"
> +                             "Use together with --baseline-rev")
> 
>     args = parser.parse_args()
> 
> +    if args.patch and (args.baseline_rev or args.report_rev):
> +        print("ERROR: '--patch' argument can't be used with '--baseline-rev'"
> +              " or '--report-rev'.")
> +        sys.exit(1)
> +
> +    if bool(args.baseline_rev) != bool(args.report_rev):
> +        print("ERROR: '--baseline-rev' must be used together with "
> +              "'--report-rev'.")
> +        sys.exit(1)
> +
>     if args.out == "stdout":
>         file_out = sys.stdout
>     else:
> @@ -63,11 +90,35 @@ def main(argv):
>         new_rep.parse()
>         debug.debug_print_parsed_report(new_rep)
>         log_info(" [OK]")
> -    except ReportError as e:
> +        diff_source = None
> +        if args.patch:
> +            diff_source = os.path.realpath(args.patch)
> +        elif args.baseline_rev:
> +            git_diff = invoke_command(
> +                "git diff --git-dir={} -C -C {}..{}".format(repo_dir,
> +                                                            args.baseline_rev,
> +                                                            args.report_rev),
> +                True, "Error occured invoking:\n{}\n\n{}"
> +            )

I’ve noticed now an issue here, when using --baseline-rev/--report-rev, the fix is this one:

diff --git a/xen/scripts/diff-report.py b/xen/scripts/diff-report.py
index d608e3a05aa1..636f98f5eebe 100755
--- a/xen/scripts/diff-report.py
+++ b/xen/scripts/diff-report.py
@@ -95,9 +95,8 @@ def main(argv):
             diff_source = os.path.realpath(args.patch)
         elif args.baseline_rev:
             git_diff = invoke_command(
-                "git diff --git-dir={} -C -C {}..{}".format(repo_dir,
-                                                            args.baseline_rev,
-                                                            args.report_rev),
+                "git --git-dir={}/.git diff -C -C {}..{}"
+                .format(repo_dir, args.baseline_rev, args.report_rev),
                 True, "Error occured invoking:\n{}\n\n{}"
             )
             diff_source = git_diff.splitlines(keepends=True)

I’ll wait for other feedback on the patch before sending it again.
Stefano Stabellini May 25, 2023, 1:18 a.m. UTC | #2
On Fri, 19 May 2023, Luca Fancellu wrote:
> > On 19 May 2023, at 10:46, Luca Fancellu <Luca.Fancellu@arm.com> wrote:
> > 
> > Add a feature to the diff-report.py script that improves the comparison
> > between two analysis report, one from a baseline codebase and the other
> > from the changes applied to the baseline.
> > 
> > The comparison between reports of different codebase is an issue because
> > entries in the baseline could have been moved in position due to addition
> > or deletion of unrelated lines or can disappear because of deletion of
> > the interested line, making the comparison between two revisions of the
> > code harder.
> > 
> > Having a baseline report, a report of the codebase with the changes
> > called "new report" and a git diff format file that describes the
> > changes happened to the code from the baseline, this feature can
> > understand which entries from the baseline report are deleted or shifted
> > in position due to changes to unrelated lines and can modify them as
> > they will appear in the "new report".
> > 
> > Having the "patched baseline" and the "new report", now it's simple
> > to make the diff between them and print only the entry that are new.
> > 
> > Signed-off-by: Luca Fancellu <luca.fancellu@arm.com>
> > ---
> > Changes from v1:
> > - Made the script compatible with python2 (Stefano)
> > ---
> > xen/scripts/diff-report.py                    |  55 ++++-
> > xen/scripts/xen_analysis/diff_tool/debug.py   |  21 ++
> > xen/scripts/xen_analysis/diff_tool/report.py  |  87 +++++++
> > .../diff_tool/unified_format_parser.py        | 232 ++++++++++++++++++
> > 4 files changed, 393 insertions(+), 2 deletions(-)
> > create mode 100644 xen/scripts/xen_analysis/diff_tool/unified_format_parser.py
> > 
> > diff --git a/xen/scripts/diff-report.py b/xen/scripts/diff-report.py
> > index f97cb2355cc3..d608e3a05aa1 100755
> > --- a/xen/scripts/diff-report.py
> > +++ b/xen/scripts/diff-report.py
> > @@ -7,6 +7,10 @@ from argparse import ArgumentParser
> > from xen_analysis.diff_tool.cppcheck_report import CppcheckReport
> > from xen_analysis.diff_tool.debug import Debug
> > from xen_analysis.diff_tool.report import ReportError
> > +from xen_analysis.diff_tool.unified_format_parser import \
> > +    (UnifiedFormatParser, UnifiedFormatParseError)
> > +from xen_analysis.settings import repo_dir
> > +from xen_analysis.utils import invoke_command
> > 
> > 
> > def log_info(text, end='\n'):
> > @@ -36,9 +40,32 @@ def main(argv):
> >                              "against the baseline.")
> >     parser.add_argument("-v", "--verbose", action='store_true',
> >                         help="Print more informations during the run.")
> > +    parser.add_argument("--patch", type=str,
> > +                        help="The patch file containing the changes to the "
> > +                             "code, from the baseline analysis result to the "
> > +                             "'check report' analysis result.\n"
> > +                             "Do not use with --baseline-rev/--report-rev")
> > +    parser.add_argument("--baseline-rev", type=str,
> > +                        help="Revision or SHA of the codebase analysed to "
> > +                             "create the baseline report.\n"
> > +                             "Use together with --report-rev")
> > +    parser.add_argument("--report-rev", type=str,
> > +                        help="Revision or SHA of the codebase analysed to "
> > +                             "create the 'check report'.\n"
> > +                             "Use together with --baseline-rev")
> > 
> >     args = parser.parse_args()
> > 
> > +    if args.patch and (args.baseline_rev or args.report_rev):
> > +        print("ERROR: '--patch' argument can't be used with '--baseline-rev'"
> > +              " or '--report-rev'.")
> > +        sys.exit(1)
> > +
> > +    if bool(args.baseline_rev) != bool(args.report_rev):
> > +        print("ERROR: '--baseline-rev' must be used together with "
> > +              "'--report-rev'.")
> > +        sys.exit(1)
> > +
> >     if args.out == "stdout":
> >         file_out = sys.stdout
> >     else:
> > @@ -63,11 +90,35 @@ def main(argv):
> >         new_rep.parse()
> >         debug.debug_print_parsed_report(new_rep)
> >         log_info(" [OK]")
> > -    except ReportError as e:
> > +        diff_source = None
> > +        if args.patch:
> > +            diff_source = os.path.realpath(args.patch)
> > +        elif args.baseline_rev:
> > +            git_diff = invoke_command(
> > +                "git diff --git-dir={} -C -C {}..{}".format(repo_dir,
> > +                                                            args.baseline_rev,
> > +                                                            args.report_rev),
> > +                True, "Error occured invoking:\n{}\n\n{}"
> > +            )
> 
> I’ve noticed now an issue here, when using --baseline-rev/--report-rev, the fix is this one:
> 
> diff --git a/xen/scripts/diff-report.py b/xen/scripts/diff-report.py
> index d608e3a05aa1..636f98f5eebe 100755
> --- a/xen/scripts/diff-report.py
> +++ b/xen/scripts/diff-report.py
> @@ -95,9 +95,8 @@ def main(argv):
>              diff_source = os.path.realpath(args.patch)
>          elif args.baseline_rev:
>              git_diff = invoke_command(
> -                "git diff --git-dir={} -C -C {}..{}".format(repo_dir,
> -                                                            args.baseline_rev,
> -                                                            args.report_rev),
> +                "git --git-dir={}/.git diff -C -C {}..{}"
> +                .format(repo_dir, args.baseline_rev, args.report_rev),
>                  True, "Error occured invoking:\n{}\n\n{}"
>              )
>              diff_source = git_diff.splitlines(keepends=True)
> 
> I’ll wait for other feedback on the patch before sending it again.

With this change:

Acked-by: Stefano Stabellini <sstabellini@kernel.org>
Tested-by: Stefano Stabellini <sstabellini@kernel.org>
Luca Fancellu May 25, 2023, 8:08 a.m. UTC | #3
>>>    if args.out == "stdout":
>>>        file_out = sys.stdout
>>>    else:
>>> @@ -63,11 +90,35 @@ def main(argv):
>>>        new_rep.parse()
>>>        debug.debug_print_parsed_report(new_rep)
>>>        log_info(" [OK]")
>>> -    except ReportError as e:
>>> +        diff_source = None
>>> +        if args.patch:
>>> +            diff_source = os.path.realpath(args.patch)
>>> +        elif args.baseline_rev:
>>> +            git_diff = invoke_command(
>>> +                "git diff --git-dir={} -C -C {}..{}".format(repo_dir,
>>> +                                                            args.baseline_rev,
>>> +                                                            args.report_rev),
>>> +                True, "Error occured invoking:\n{}\n\n{}"
>>> +            )
>> 
>> I’ve noticed now an issue here, when using --baseline-rev/--report-rev, the fix is this one:
>> 
>> diff --git a/xen/scripts/diff-report.py b/xen/scripts/diff-report.py
>> index d608e3a05aa1..636f98f5eebe 100755
>> --- a/xen/scripts/diff-report.py
>> +++ b/xen/scripts/diff-report.py
>> @@ -95,9 +95,8 @@ def main(argv):
>>             diff_source = os.path.realpath(args.patch)
>>         elif args.baseline_rev:
>>             git_diff = invoke_command(
>> -                "git diff --git-dir={} -C -C {}..{}".format(repo_dir,
>> -                                                            args.baseline_rev,
>> -                                                            args.report_rev),
>> +                "git --git-dir={}/.git diff -C -C {}..{}"
>> +                .format(repo_dir, args.baseline_rev, args.report_rev),
>>                 True, "Error occured invoking:\n{}\n\n{}"
>>             )
>>             diff_source = git_diff.splitlines(keepends=True)
>> 
>> I’ll wait for other feedback on the patch before sending it again.
> 
> With this change:
> 
> Acked-by: Stefano Stabellini <sstabellini@kernel.org>
> Tested-by: Stefano Stabellini <sstabellini@kernel.org>

Thank you Stefano,

I will push the serie with the fix and your tags
diff mbox series

Patch

diff --git a/xen/scripts/diff-report.py b/xen/scripts/diff-report.py
index f97cb2355cc3..d608e3a05aa1 100755
--- a/xen/scripts/diff-report.py
+++ b/xen/scripts/diff-report.py
@@ -7,6 +7,10 @@  from argparse import ArgumentParser
 from xen_analysis.diff_tool.cppcheck_report import CppcheckReport
 from xen_analysis.diff_tool.debug import Debug
 from xen_analysis.diff_tool.report import ReportError
+from xen_analysis.diff_tool.unified_format_parser import \
+    (UnifiedFormatParser, UnifiedFormatParseError)
+from xen_analysis.settings import repo_dir
+from xen_analysis.utils import invoke_command
 
 
 def log_info(text, end='\n'):
@@ -36,9 +40,32 @@  def main(argv):
                              "against the baseline.")
     parser.add_argument("-v", "--verbose", action='store_true',
                         help="Print more informations during the run.")
+    parser.add_argument("--patch", type=str,
+                        help="The patch file containing the changes to the "
+                             "code, from the baseline analysis result to the "
+                             "'check report' analysis result.\n"
+                             "Do not use with --baseline-rev/--report-rev")
+    parser.add_argument("--baseline-rev", type=str,
+                        help="Revision or SHA of the codebase analysed to "
+                             "create the baseline report.\n"
+                             "Use together with --report-rev")
+    parser.add_argument("--report-rev", type=str,
+                        help="Revision or SHA of the codebase analysed to "
+                             "create the 'check report'.\n"
+                             "Use together with --baseline-rev")
 
     args = parser.parse_args()
 
+    if args.patch and (args.baseline_rev or args.report_rev):
+        print("ERROR: '--patch' argument can't be used with '--baseline-rev'"
+              " or '--report-rev'.")
+        sys.exit(1)
+
+    if bool(args.baseline_rev) != bool(args.report_rev):
+        print("ERROR: '--baseline-rev' must be used together with "
+              "'--report-rev'.")
+        sys.exit(1)
+
     if args.out == "stdout":
         file_out = sys.stdout
     else:
@@ -63,11 +90,35 @@  def main(argv):
         new_rep.parse()
         debug.debug_print_parsed_report(new_rep)
         log_info(" [OK]")
-    except ReportError as e:
+        diff_source = None
+        if args.patch:
+            diff_source = os.path.realpath(args.patch)
+        elif args.baseline_rev:
+            git_diff = invoke_command(
+                "git diff --git-dir={} -C -C {}..{}".format(repo_dir,
+                                                            args.baseline_rev,
+                                                            args.report_rev),
+                True, "Error occured invoking:\n{}\n\n{}"
+            )
+            diff_source = git_diff.splitlines(keepends=True)
+        if diff_source:
+            log_info("Parsing changes...", "")
+            diffs = UnifiedFormatParser(diff_source)
+            debug.debug_print_parsed_diff(diffs)
+            log_info(" [OK]")
+    except (ReportError, UnifiedFormatParseError) as e:
         print("ERROR: {}".format(e))
         sys.exit(1)
 
-    output = new_rep - baseline
+    if args.patch or args.baseline_rev:
+        log_info("Patching baseline...", "")
+        baseline_patched = baseline.patch(diffs)
+        debug.debug_print_patched_report(baseline_patched)
+        log_info(" [OK]")
+        output = new_rep - baseline_patched
+    else:
+        output = new_rep - baseline
+
     print(output, end="", file=file_out)
 
     if len(output) > 0:
diff --git a/xen/scripts/xen_analysis/diff_tool/debug.py b/xen/scripts/xen_analysis/diff_tool/debug.py
index 65cca2464110..fcf1d861b5cf 100644
--- a/xen/scripts/xen_analysis/diff_tool/debug.py
+++ b/xen/scripts/xen_analysis/diff_tool/debug.py
@@ -3,6 +3,7 @@ 
 from __future__ import print_function
 import os
 from .report import Report
+from .unified_format_parser import UnifiedFormatParser
 
 
 class Debug:
@@ -38,3 +39,23 @@  class Debug:
         if not self.args.debug:
             return
         self.__debug_print_report(report, ".parsed")
+
+    def debug_print_patched_report(self, report):
+        # type: (Report) -> None
+        if not self.args.debug:
+            return
+        # The patched report contains already .patched in its name
+        self.__debug_print_report(report, "")
+
+    def debug_print_parsed_diff(self, diff):
+        # type: (UnifiedFormatParser) -> None
+        if not self.args.debug:
+            return
+        diff_filename = diff.get_diff_path()
+        out_pathname = self.__get_debug_out_filename(diff_filename, ".parsed")
+        try:
+            with open(out_pathname, "wt") as outfile:
+                for change_obj in diff.get_change_sets().values():
+                    print(change_obj, end="", file=outfile)
+        except OSError as e:
+            print("ERROR: Issue opening file {}: {}".format(out_pathname, e))
diff --git a/xen/scripts/xen_analysis/diff_tool/report.py b/xen/scripts/xen_analysis/diff_tool/report.py
index 4a303d61b3ea..b80eb31114f0 100644
--- a/xen/scripts/xen_analysis/diff_tool/report.py
+++ b/xen/scripts/xen_analysis/diff_tool/report.py
@@ -1,6 +1,7 @@ 
 #!/usr/bin/env python3
 
 import os
+from .unified_format_parser import UnifiedFormatParser, ChangeSet
 
 
 class ReportError(Exception):
@@ -47,6 +48,92 @@  class Report(object):
             self.__entries[entry_path] = [entry]
         self.__last_line_order += 1
 
+    def remove_entries(self, entry_file_path):
+        # type: (str) -> None
+        del self.__entries[entry_file_path]
+
+    def remove_entry(self, entry_path, line_id):
+        # type: (str, int) -> None
+        if entry_path in self.__entries.keys():
+            len_entry_path = len(self.__entries[entry_path])
+            if len_entry_path == 1:
+                del self.__entries[entry_path]
+            else:
+                if line_id in self.__entries[entry_path]:
+                    self.__entries[entry_path].remove(line_id)
+
+    def patch(self, diff_obj):
+        # type: (UnifiedFormatParser) -> Report
+        filename, file_extension = os.path.splitext(self.__path)
+        patched_report = self.__class__(filename + ".patched" + file_extension)
+        remove_files = []
+        rename_files = []
+        remove_entry = []
+        ChangeMode = ChangeSet.ChangeMode
+
+        # Copy entries from this report to the report we are going to patch
+        for entries in self.__entries.values():
+            for entry in entries:
+                patched_report.add_entry(entry.file_path, entry.line_number,
+                                         entry.text)
+
+        # Patch the output report
+        patched_rep_entries = patched_report.get_report_entries()
+        for file_diff, change_obj in diff_obj.get_change_sets().items():
+            if change_obj.is_change_mode(ChangeMode.COPY):
+                # Copy the original entry pointed by change_obj.orig_file into
+                # a new key in the patched report named change_obj.dst_file,
+                # that here is file_diff variable content, because this
+                # change_obj is pushed into the change_sets with the
+                # change_obj.dst_file key
+                if change_obj.orig_file in self.__entries.keys():
+                    for entry in self.__entries[change_obj.orig_file]:
+                        patched_report.add_entry(file_diff,
+                                                 entry.line_number,
+                                                 entry.text)
+
+            if file_diff in patched_rep_entries.keys():
+                if change_obj.is_change_mode(ChangeMode.DELETE):
+                    # No need to check changes here, just remember to delete
+                    # the file from the report
+                    remove_files.append(file_diff)
+                    continue
+                elif change_obj.is_change_mode(ChangeMode.RENAME):
+                    # Remember to rename the file entry on this report
+                    rename_files.append(change_obj)
+
+                for line_num, change_type in change_obj.get_change_set():
+                    len_rep = len(patched_rep_entries[file_diff])
+                    for i in range(len_rep):
+                        rep_item = patched_rep_entries[file_diff][i]
+                        if change_type == ChangeSet.ChangeType.REMOVE:
+                            if rep_item.line_number == line_num:
+                                # This line is removed with this changes,
+                                # append to the list of entries to be removed
+                                remove_entry.append(rep_item)
+                            elif rep_item.line_number > line_num:
+                                rep_item.line_number -= 1
+                        elif change_type == ChangeSet.ChangeType.ADD:
+                            if rep_item.line_number >= line_num:
+                                rep_item.line_number += 1
+                    # Remove deleted entries from the list
+                    if len(remove_entry) > 0:
+                        for entry in remove_entry:
+                            patched_report.remove_entry(entry.file_path,
+                                                        entry.line_id)
+                        del remove_entry[:]
+
+        if len(remove_files) > 0:
+            for file_name in remove_files:
+                patched_report.remove_entries(file_name)
+
+        if len(rename_files) > 0:
+            for change_obj in rename_files:
+                patched_rep_entries[change_obj.dst_file] = \
+                    patched_rep_entries.pop(change_obj.orig_file)
+
+        return patched_report
+
     def to_list(self):
         # type: () -> list
         report_list = []
diff --git a/xen/scripts/xen_analysis/diff_tool/unified_format_parser.py b/xen/scripts/xen_analysis/diff_tool/unified_format_parser.py
new file mode 100644
index 000000000000..8b3fbc318df7
--- /dev/null
+++ b/xen/scripts/xen_analysis/diff_tool/unified_format_parser.py
@@ -0,0 +1,232 @@ 
+#!/usr/bin/env python3
+
+import re
+import sys
+
+try:
+    from enum import Enum
+except Exception:
+    if sys.version_info[0] == 2:
+        print("Please install enum34 package when using python 2.")
+    else:
+        print("Please use python version 3.5 or above.")
+    sys.exit(1)
+
+try:
+    from typing import Tuple
+except Exception:
+    if sys.version_info[0] == 2:
+        print("Please install typing package when using python 2.")
+    else:
+        print("Please use python version 3.5 or above.")
+    sys.exit(1)
+
+
+class UnifiedFormatParseError(Exception):
+    pass
+
+
+class ParserState(Enum):
+    FIND_DIFF_HEADER = 0
+    REGISTER_CHANGES = 1
+    FIND_HUNK_OR_DIFF_HEADER = 2
+
+
+class ChangeSet(object):
+    class ChangeType(Enum):
+        REMOVE = 0
+        ADD = 1
+
+    class ChangeMode(Enum):
+        NONE = 0
+        CHANGE = 1
+        RENAME = 2
+        DELETE = 3
+        COPY = 4
+
+    def __init__(self, a_file, b_file):
+        # type: (str, str) -> None
+        self.orig_file = a_file
+        self.dst_file = b_file
+        self.change_mode = ChangeSet.ChangeMode.NONE
+        self.__changes = []
+
+    def __str__(self):
+        # type: () -> str
+        str_out = "{}: {} -> {}:\n{}\n".format(
+            str(self.change_mode), self.orig_file, self.dst_file,
+            str(self.__changes)
+        )
+        return str_out
+
+    def set_change_mode(self, change_mode):
+        # type: (ChangeMode) -> None
+        self.change_mode = change_mode
+
+    def is_change_mode(self, change_mode):
+        # type: (ChangeMode) -> bool
+        return self.change_mode == change_mode
+
+    def add_change(self, line_number, change_type):
+        # type: (int, ChangeType) -> None
+        self.__changes.append((line_number, change_type))
+
+    def get_change_set(self):
+        # type: () -> dict
+        return self.__changes
+
+
+class UnifiedFormatParser(object):
+    def __init__(self, args):
+        # type: (str | list) -> None
+        if isinstance(args, str):
+            self.__diff_file = args
+            try:
+                with open(self.__diff_file, "rt") as infile:
+                    self.__diff_lines = infile.readlines()
+            except OSError as e:
+                raise UnifiedFormatParseError(
+                    "Issue with reading file {}: {}"
+                    .format(self.__diff_file, e)
+                )
+        elif isinstance(args, list):
+            self.__diff_file = "git-diff-local.txt"
+            self.__diff_lines = args
+        else:
+            raise UnifiedFormatParseError(
+                "UnifiedFormatParser constructor called with wrong arguments")
+
+        self.__git_diff_header = re.compile(r'^diff --git a/(.*) b/(.*)$')
+        self.__git_hunk_header = \
+            re.compile(r'^@@ -\d+,(\d+) \+(\d+),(\d+) @@.*$')
+        self.__diff_set = {}
+        self.__parse()
+
+    def get_diff_path(self):
+        # type: () -> str
+        return self.__diff_file
+
+    def add_change_set(self, change_set):
+        # type: (ChangeSet) -> None
+        if not change_set.is_change_mode(ChangeSet.ChangeMode.NONE):
+            if change_set.is_change_mode(ChangeSet.ChangeMode.COPY):
+                # Add copy change mode items using the dst_file key, because
+                # there might be other changes for the orig_file in this diff
+                self.__diff_set[change_set.dst_file] = change_set
+            else:
+                self.__diff_set[change_set.orig_file] = change_set
+
+    def __parse(self):
+        # type: () -> None
+        def parse_diff_header(line):
+            # type: (str) -> ChangeSet | None
+            change_item = None
+            diff_head = self.__git_diff_header.match(line)
+            if diff_head and diff_head.group(1) and diff_head.group(2):
+                change_item = ChangeSet(diff_head.group(1), diff_head.group(2))
+
+            return change_item
+
+        def parse_hunk_header(line):
+            # type: (str) -> Tuple[int, int, int]
+            file_linenum = -1
+            hunk_a_linemax = -1
+            hunk_b_linemax = -1
+            hunk_head = self.__git_hunk_header.match(line)
+            if hunk_head and hunk_head.group(1) and hunk_head.group(2) \
+               and hunk_head.group(3):
+                file_linenum = int(hunk_head.group(2))
+                hunk_a_linemax = int(hunk_head.group(1))
+                hunk_b_linemax = int(hunk_head.group(3))
+
+            return (file_linenum, hunk_a_linemax, hunk_b_linemax)
+
+        file_linenum = 0
+        hunk_a_linemax = 0
+        hunk_b_linemax = 0
+        diff_elem = None
+        parse_state = ParserState.FIND_DIFF_HEADER
+        ChangeMode = ChangeSet.ChangeMode
+        ChangeType = ChangeSet.ChangeType
+
+        for line in self.__diff_lines:
+            if parse_state == ParserState.FIND_DIFF_HEADER:
+                diff_elem = parse_diff_header(line)
+                if diff_elem:
+                    # Found the diff header, go to the next stage
+                    parse_state = ParserState.FIND_HUNK_OR_DIFF_HEADER
+            elif parse_state == ParserState.FIND_HUNK_OR_DIFF_HEADER:
+                # Here only these change modalities will be registered:
+                # deleted file mode <mode>
+                # rename from <path>
+                # rename to <path>
+                # copy from <path>
+                # copy to <path>
+                #
+                # These will be ignored:
+                # old mode <mode>
+                # new mode <mode>
+                # new file mode <mode>
+                #
+                # Also these info will be ignored
+                # similarity index <number>
+                # dissimilarity index <number>
+                # index <hash>..<hash> <mode>
+                if line.startswith("deleted file"):
+                    # If the file is deleted, register it but don't go through
+                    # the changes that will be only a set of lines removed
+                    diff_elem.set_change_mode(ChangeMode.DELETE)
+                    parse_state = ParserState.FIND_DIFF_HEADER
+                elif line.startswith("new file"):
+                    # If the file is new, skip it, as it doesn't give any
+                    # useful information on the report translation
+                    parse_state = ParserState.FIND_DIFF_HEADER
+                elif line.startswith("rename to"):
+                    # Renaming operation can be a pure renaming or a rename
+                    # and a set of change, so keep looking for the hunk
+                    # header
+                    diff_elem.set_change_mode(ChangeMode.RENAME)
+                elif line.startswith("copy to"):
+                    # This is a copy operation, mark it
+                    diff_elem.set_change_mode(ChangeMode.COPY)
+                else:
+                    # Look for the hunk header
+                    (file_linenum, hunk_a_linemax, hunk_b_linemax) = \
+                        parse_hunk_header(line)
+                    if file_linenum >= 0:
+                        if diff_elem.is_change_mode(ChangeMode.NONE):
+                            # The file has only changes
+                            diff_elem.set_change_mode(ChangeMode.CHANGE)
+                        parse_state = ParserState.REGISTER_CHANGES
+                    else:
+                        # ... or there could be a diff header
+                        new_diff_elem = parse_diff_header(line)
+                        if new_diff_elem:
+                            # Found a diff header, register the last change
+                            # item
+                            self.add_change_set(diff_elem)
+                            diff_elem = new_diff_elem
+            elif parse_state == ParserState.REGISTER_CHANGES:
+                if (hunk_b_linemax > 0) and line.startswith("+"):
+                    diff_elem.add_change(file_linenum, ChangeType.ADD)
+                    hunk_b_linemax -= 1
+                elif (hunk_a_linemax > 0) and line.startswith("-"):
+                    diff_elem.add_change(file_linenum, ChangeType.REMOVE)
+                    hunk_a_linemax -= 1
+                    file_linenum -= 1
+                elif ((hunk_a_linemax + hunk_b_linemax) > 0) and \
+                        line.startswith(" "):
+                    hunk_a_linemax -= 1 if (hunk_a_linemax > 0) else 0
+                    hunk_b_linemax -= 1 if (hunk_b_linemax > 0) else 0
+
+                if (hunk_a_linemax + hunk_b_linemax) <= 0:
+                    parse_state = ParserState.FIND_HUNK_OR_DIFF_HEADER
+
+                file_linenum += 1
+
+        if diff_elem is not None:
+            self.add_change_set(diff_elem)
+
+    def get_change_sets(self):
+        # type: () -> dict
+        return self.__diff_set