Git graph diff tool

README.md

@@ -1,11 +1,13 @@
 # graph-diff
 Utilities to view diff between graphs
 
-# Getting starget
+# Getting started
 
 ## Install prerequisites 
-1. graph-easy
-
+Debian / Ubuntu:
+```
+sudo apt-get install libgraph-easy-perl
+```
 ## Install
 ```
 git clone https://github.com/yeger00/graph-diff
@@ -16,9 +18,24 @@ pip install -e .
 ```
 cat samples/before.dot | graph-easy --as boxart
 cat samples/after.dot | graph-easy --as boxart
-python -m graphdiff samples/before.dot samples/after.dot ./diff.dot
+python -m graphdiff samples/before.dot samples/after.dot > ./diff.dot
 cat ./diff.dot | ./diff-graph-color
 ```
 
-# git-diff
-TODO
+# git-graph-diff-tool
+It is possible to use graph-diff with git, with `git-graph-diff-tool` provided in this library. An usage example:
+![](images/git-log-example.gif?raw=true "git-graph-diff-tool example")
+
+## Install
+For every repository you would like to install you need to add to .gitattributes file a rules to know how to handle .dot files. For example:
+```
+echo "*.dot diff=graph_diff" >> .gitattributes
+```
+Then, configure the difftool to be the `git-graph-diff-tool`. For example:
+```
+git config diff.graph_diff.command /path/to/git-graph-diff-tool
+```
+Then, you can use git as usual, while adding `--ext-diff` flag to enable external difftools.
+```
+git log -p --ext-diff
+```

git-graph-diff-tool

@@ -0,0 +1,62 @@
+#!/usr/bin/env sh
+
+# Git graph-diff tool.
+# GIT_EXTERNAL_DIFF command line arguments are available <here>
+
+set -eu
+
+readonly SCRIPT_DIR=$(dirname $(readlink -f $0))
+readonly SCRIPT=$(basename $(readlink -f $0))
+
+perror()
+{
+    echo "${SCRIPT}: ERROR: ${@}" >&2
+    exit 1
+}
+
+help()
+{
+(
+    cat <<EOF
+    Git graph-diff tool.
+    See GIT_EXTERNAL_DIFF documentation for explanation of the arguments.
+
+    ./${SCRIPT} [-h] [-x] PATH OLD-FILE OLD-HEX OLD-MODE NEW-FILE NEW-HEX NEW-MODE
+    | * -h - print this help.
+    | * -x - set bash's -x flag.
+EOF
+) | sed -r 's/^\s*\|?//'
+}
+
+while getopts ":hx" option
+do
+    case "${option}" in
+        h)  help
+            exit 0
+            ;;
+
+        x)  set -x
+            ;;
+
+        \?) perror "unknown option -${OPTARG}"
+            ;;
+    esac
+done
+shift $((OPTIND-1))
+
+# validate number of arguments left
+if [ "${#}" -ne 7 ]
+then
+    perror "Invalid number of arguments (use -h for help)."
+fi
+
+path="${1}"
+old_file="${2}"
+old_hex="${3}"
+old_mode="${4}"
+new_file="${5}"
+new_hex="${6}"
+new_mode="${7}"
+
+python -m graphdiff "${old_file}" "${new_file}" | ${SCRIPT_DIR}/diff-graph-color
+

graphdiff/__main__.py

@@ -8,8 +8,14 @@ def load_graph(path):
     '''
     Loads a graph from .dot file into a Graph() object.
     '''
-    pydot_graph = pydot.graph_from_dot_file(path)[0]
-    return graphdiff.from_dot(pydot_graph) 
+    with open(path) as f:
+        data = f.read()
+    graph = graphdiff.Graph()
+    if data:
+        # TODO: handle multiple graphs
+        pydot_graph = pydot.graph_from_dot_data(data)[0]
+        graph = graphdiff.from_dot(pydot_graph) 
+    return graph
 
 
 def save_graph(graph, path):
@@ -26,8 +32,8 @@ def main():
     before_graph = load_graph(sys.argv[1])
     after_graph = load_graph(sys.argv[2])
     diff = graphdiff.generate_diff_graph(before_graph, after_graph)
-    save_graph(diff, sys.argv[3])
-    # print_graph(diff)
+    # save_graph(diff, sys.argv[3])
+    print_graph(diff)
 
 
 if __name__ == "__main__":

graphdiff/graphdiff.py

@@ -112,7 +112,8 @@ def remove_quotes(pydot_graph):
         node.set_label(node.get_label().replace('"', ''))
 
     for edge in pydot_graph.get_edges():
-        edge.set_label(edge.get_label().replace('"', ''))
+        if edge.get_label():
+            edge.set_label(edge.get_label().replace('"', ''))
 
 def from_dot(pydot_graph):
     """Generated a graph from pydot graph."""