From 63755f050629be441e471b9f09cfb60dfab94b32 Mon Sep 17 00:00:00 2001
From: tennashi <tennashio@gmail.com>
Date: Fri, 10 Sep 2021 00:32:10 +0900
Subject: [PATCH] initial commit

---
 LICENSE   |  21 +++++++++++
 README.md |  19 ++++++++++
 diff.ts   | 104 ++++++++++++++++++++++++++++++++++++++++++++++++++++++
 mod.ts    |   1 +
 4 files changed, 145 insertions(+)
 create mode 100644 LICENSE
 create mode 100644 README.md
 create mode 100644 diff.ts
 create mode 100644 mod.ts

diff --git a/LICENSE b/LICENSE
new file mode 100644
index 0000000..5223af9
--- /dev/null
+++ b/LICENSE
@@ -0,0 +1,21 @@
+MIT License
+
+Copyright (c) 2021 tennashi
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.
diff --git a/README.md b/README.md
new file mode 100644
index 0000000..b03fc1b
--- /dev/null
+++ b/README.md
@@ -0,0 +1,19 @@
+# diff-parser
+Parse unified diff format
+
+## Usage
+
+```ts
+import { parse } from "https://deno.land/x/diff_parser/mod.ts";
+
+const process = Deno.run({
+  cmd: ["git", "diff", "--no-color"]
+  stdout: "piped",
+});
+
+const output = await process.output();
+const diffText = new TextDecoder().decode(output);
+process.close();
+
+parse(diffText);
+```
diff --git a/diff.ts b/diff.ts
new file mode 100644
index 0000000..9af6dd0
--- /dev/null
+++ b/diff.ts
@@ -0,0 +1,104 @@
+export type Diff = {
+  beforeFileName: string
+  afterFileName: string
+  hunks: Hunk[]
+}
+
+type Hunk = {
+  header: HunkHeader
+  lines: Line[]
+}
+
+type HunkHeader = {
+  beforeLines: number
+  afterLines: number
+  beforeStartLine: number
+  afterStartLine: number
+}
+
+type Line = {
+  text: string
+  mark: 'add' | 'delete' | 'nomodified'
+}
+
+const hunkHeaderRegexp = /@@ -(\d+),?(\d*) \+(\d+),?(\d*) @@/
+
+export function parse(text: string): Diff[] {
+  const diffs: Diff[] = [];
+  let currentDiffIndex = 0;
+  let currentHunkIndex = 0;
+
+  text.split('\n').forEach((l) => {
+    if (l.startsWith('---')) {
+      diffs.push({
+        beforeFileName: '',
+        afterFileName: '',
+        hunks: [],
+      });
+
+      currentDiffIndex = diffs.length - 1;
+      currentHunkIndex = 0;
+
+      diffs[currentDiffIndex].beforeFileName = l.slice(4);
+
+      return;
+    }
+
+    if (l.startsWith('+++')) {
+      diffs[currentDiffIndex].afterFileName = l.slice(4);
+
+      return;
+    }
+
+    if (l.startsWith('@@')) {
+      const matched = l.match(hunkHeaderRegexp);
+
+      if (!matched) {
+        return;
+      }
+
+      diffs[currentDiffIndex].hunks.push({
+        header: {
+          beforeStartLine: Number(matched[1]),
+          beforeLines: matched[2] ? Number(matched[2]) : 1,
+          afterStartLine: Number(matched[3]),
+          afterLines: matched[4] ? Number(matched[4]) : 1,
+        },
+        lines: [],
+      });
+
+      currentHunkIndex = diffs[currentDiffIndex].hunks.length - 1;
+
+      return;
+    }
+
+    if (l.startsWith('-')) {
+      diffs[currentDiffIndex].hunks[currentHunkIndex].lines.push({
+        text: l.slice(1),
+        mark: 'delete',
+      });
+
+      return;
+    }
+
+    if (l.startsWith('+')) {
+      diffs[currentDiffIndex].hunks[currentHunkIndex].lines.push({
+        text: l.slice(1),
+        mark: 'add',
+      });
+
+      return;
+    }
+
+    if (l.startsWith(' ')) {
+      diffs[currentDiffIndex].hunks[currentHunkIndex].lines.push({
+        text: l.slice(1),
+        mark: 'nomodified',
+      });
+
+      return;
+    }
+  });
+
+  return diffs;
+}
diff --git a/mod.ts b/mod.ts
new file mode 100644
index 0000000..274e1e7
--- /dev/null
+++ b/mod.ts
@@ -0,0 +1 @@
+export * from "./diff.ts";