From 459ded17090a366a7097271ff8ef31bbac43d794 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Gon=C3=A7alo=20Val=C3=A9rio?= <gon@ovalerio.net>
Date: Sun, 22 Nov 2020 00:17:22 +0000
Subject: [PATCH] step fourty four: print diff of commit

---
 Cargo.lock  | 94 +++++++++++++++++++++++++++++++++++++++++++++++++++++
 Cargo.toml  |  1 +
 src/diff.rs | 38 +++++++++++++++++++++-
 3 files changed, 132 insertions(+), 1 deletion(-)

diff --git a/Cargo.lock b/Cargo.lock
index fcd5089..08e54ae 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -81,6 +81,17 @@ dependencies = [
  "version_check",
 ]
 
+[[package]]
+name = "getrandom"
+version = "0.1.15"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "fc587bc0ec293155d5bfa6b9891ec18a1e330c234f896ea47fbada4cadbe47e6"
+dependencies = [
+ "cfg-if",
+ "libc",
+ "wasi",
+]
+
 [[package]]
 name = "hermit-abi"
 version = "0.1.16"
@@ -102,12 +113,75 @@ version = "0.3.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "624a8340c38c1b80fd549087862da4ba43e08858af025b236e509b6649fc13d5"
 
+[[package]]
+name = "ppv-lite86"
+version = "0.2.10"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "ac74c624d6b2d21f425f752262f42188365d7b8ff1aff74c82e45136510a4857"
+
+[[package]]
+name = "rand"
+version = "0.7.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "6a6b1679d49b24bbfe0c803429aa1874472f50d9b363131f0e89fc356b544d03"
+dependencies = [
+ "getrandom",
+ "libc",
+ "rand_chacha",
+ "rand_core",
+ "rand_hc",
+]
+
+[[package]]
+name = "rand_chacha"
+version = "0.2.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "f4c8ed856279c9737206bf725bf36935d8666ead7aa69b52be55af369d193402"
+dependencies = [
+ "ppv-lite86",
+ "rand_core",
+]
+
+[[package]]
+name = "rand_core"
+version = "0.5.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "90bde5296fc891b0cef12a6d03ddccc162ce7b2aff54160af9338f8d40df6d19"
+dependencies = [
+ "getrandom",
+]
+
+[[package]]
+name = "rand_hc"
+version = "0.2.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "ca3129af7b92a17112d59ad498c6f81eaf463253766b90396d39ea7a39d6613c"
+dependencies = [
+ "rand_core",
+]
+
+[[package]]
+name = "redox_syscall"
+version = "0.1.57"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "41cc0f7e4d5d4544e8861606a285bb08d3e70712ccc7d2b84d7c0ccfaf4b05ce"
+
+[[package]]
+name = "remove_dir_all"
+version = "0.5.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "3acd125665422973a33ac9d3dd2df85edad0f4ae9b00dafb1a05e43a9f5ef8e7"
+dependencies = [
+ "winapi",
+]
+
 [[package]]
 name = "rgit"
 version = "0.1.0"
 dependencies = [
  "clap",
  "sha-1",
+ "tempfile",
  "walkdir",
 ]
 
@@ -139,6 +213,20 @@ version = "0.8.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "8ea5119cdb4c55b55d432abb513a0429384878c15dde60cc77b1c99de1a95a6a"
 
+[[package]]
+name = "tempfile"
+version = "3.1.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "7a6e24d9338a0a5be79593e2fa15a648add6138caa803e2d5bc782c371732ca9"
+dependencies = [
+ "cfg-if",
+ "libc",
+ "rand",
+ "redox_syscall",
+ "remove_dir_all",
+ "winapi",
+]
+
 [[package]]
 name = "textwrap"
 version = "0.11.0"
@@ -183,6 +271,12 @@ dependencies = [
  "winapi-util",
 ]
 
+[[package]]
+name = "wasi"
+version = "0.9.0+wasi-snapshot-preview1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "cccddf32554fecc6acb585f82a32a72e28b48f8c4c1883ddfeeeaa96f7d8e519"
+
 [[package]]
 name = "winapi"
 version = "0.3.9"
diff --git a/Cargo.toml b/Cargo.toml
index 79d85ae..ec66057 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -10,3 +10,4 @@ edition = "2018"
 clap = "2.33.3"
 sha-1 = "0.9.1"
 walkdir = "2"
+tempfile = "3.1.0"
diff --git a/src/diff.rs b/src/diff.rs
index 4fdd388..fa0312b 100644
--- a/src/diff.rs
+++ b/src/diff.rs
@@ -1,4 +1,10 @@
 use std::collections::HashMap;
+use std::fs;
+use std::process::{Command, Stdio};
+use tempfile::NamedTempFile;
+
+#[path = "data.rs"]
+mod data;
 
 fn compare_trees(trees: Vec<HashMap<String, String>>) -> HashMap<String, Vec<String>> {
     let len_trees = trees.len();
@@ -18,6 +24,36 @@ fn compare_trees(trees: Vec<HashMap<String, String>>) -> HashMap<String, Vec<Str
     return entries;
 }
 
+fn diff_blobs(o_from: String, o_to: String, path: String) -> String {
+    let f_from = NamedTempFile::new().unwrap();
+    let f_to = NamedTempFile::new().unwrap();
+
+    if o_from != "" {
+        let content = data::get_object(o_from, "blob".to_owned());
+        fs::write(f_from.path(), content).unwrap();
+    }
+
+    if o_to != "" {
+        let content = data::get_object(o_to, "blob".to_owned());
+        fs::write(f_to.path(), content).unwrap();
+    }
+
+    let output = Command::new("diff")
+        .arg("--unified")
+        .arg("--show-c-function")
+        .arg("--label")
+        .arg(format!("a/{}", path))
+        .arg(f_from.path())
+        .arg("--label")
+        .arg(format!("a/{}", path))
+        .arg(f_to.path())
+        .stdout(Stdio::piped())
+        .output()
+        .expect("Failed to launch diff");
+
+    return String::from_utf8_lossy(&output.stdout).to_string();
+}
+
 pub fn diff_trees(t_from: HashMap<String, String>, t_to: HashMap<String, String>) -> String {
     let mut output = "".to_owned();
     let trees = vec![t_from, t_to];
@@ -25,7 +61,7 @@ pub fn diff_trees(t_from: HashMap<String, String>, t_to: HashMap<String, String>
         let o_from = oids[0].clone();
         let o_to = oids[1].clone();
         if o_from != o_to {
-            output.push_str(format!("changed {}\n", path).as_str());
+            output.push_str(diff_blobs(o_from, o_to, path.clone()).as_str());
         }
     }