Add debug logging and log stats on shortest path found

CHANGELOG.md

@@ -28,6 +28,9 @@ Removed the unused `--lang` argument.
 Difftastic now handles writing to a closed pipe (SIGPIPE) gracefully
 rather than crashing.
 
+Difftastic now has some debugging logs available. `RUST_LOG=trace`
+will show information on the route found during graph solving.
+
 ## 0.7
 
 ### Git integration

Cargo.lock

@@ -43,6 +43,12 @@ version = "1.0.69"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "e70cc2f62c6ce1868963827bd677764c62d07c3d9a3e1fb1177ee1a9ab199eb2"
 
+[[package]]
+name = "cfg-if"
+version = "1.0.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "baf1de4339761588bc0619e3cbc0120ee582ebb74b53b4efbf79117bd2da40fd"
+
 [[package]]
 name = "clap"
 version = "2.33.3"
@@ -103,7 +109,9 @@ dependencies = [
  "itertools",
  "lazy_static",
  "libc",
+ "log",
  "pretty_assertions",
+ "pretty_env_logger",
  "regex",
  "rustc-hash",
  "strsim 0.10.0",
@@ -118,6 +126,19 @@ version = "1.6.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "e78d4f1cc4ae33bbfc157ed5d5a5ef3bc29227303d595861deb238fcec4e9457"
 
+[[package]]
+name = "env_logger"
+version = "0.7.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "44533bbbb3bb3c1fa17d9f2e4e38bbbaf8396ba82193c4cb1b6445d711445d36"
+dependencies = [
+ "atty",
+ "humantime",
+ "log",
+ "regex",
+ "termcolor",
+]
+
 [[package]]
 name = "hermit-abi"
 version = "0.1.19"
@@ -127,6 +148,15 @@ dependencies = [
  "libc",
 ]
 
+[[package]]
+name = "humantime"
+version = "1.3.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "df004cfca50ef23c36850aaaa59ad52cc70d0e90243c3c7737a4dd32dc7a3c4f"
+dependencies = [
+ "quick-error",
+]
+
 [[package]]
 name = "itertools"
 version = "0.8.2"
@@ -148,6 +178,15 @@ version = "0.2.99"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "a7f823d141fe0a24df1e23b4af4e3c7ba9e5966ec514ea068c93024aa7deb765"
 
+[[package]]
+name = "log"
+version = "0.4.14"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "51b9bbe6c47d51fc3e1a9b945965946b4c44142ab8792c50835a980d362c2710"
+dependencies = [
+ "cfg-if",
+]
+
 [[package]]
 name = "memchr"
 version = "2.4.0"
@@ -175,6 +214,16 @@ dependencies = [
  "output_vt100",
 ]
 
+[[package]]
+name = "pretty_env_logger"
+version = "0.4.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "926d36b9553851b8b0005f1275891b392ee4d2d833852c417ed025477350fb9d"
+dependencies = [
+ "env_logger",
+ "log",
+]
+
 [[package]]
 name = "proc-macro2"
 version = "1.0.28"
@@ -184,6 +233,12 @@ dependencies = [
  "unicode-xid",
 ]
 
+[[package]]
+name = "quick-error"
+version = "1.2.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "a1d01941d82fa2ab50be1e79e6714289dd7cde78eba4c074bc5a4374f650dfe0"
+
 [[package]]
 name = "quote"
 version = "1.0.9"
@@ -249,6 +304,15 @@ dependencies = [
  "winapi",
 ]
 
+[[package]]
+name = "termcolor"
+version = "1.1.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "2dfed899f0eb03f32ee8c6a0aabdb8a7949659e3466561fc0adf54e26d88c5f4"
+dependencies = [
+ "winapi-util",
+]
+
 [[package]]
 name = "textwrap"
 version = "0.11.0"
@@ -308,6 +372,15 @@ version = "0.4.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "ac3b87c63620426dd9b991e5ce0329eff545bccbbb34f3be09ff6fb6ab51b7b6"
 
+[[package]]
+name = "winapi-util"
+version = "0.1.5"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "70ec6ce85bb158151cae5e5c87f95a8e97d2c0c4b001223f33a334e3ce5de178"
+dependencies = [
+ "winapi",
+]
+
 [[package]]
 name = "winapi-x86_64-pc-windows-gnu"
 version = "0.4.0"

Cargo.toml

@@ -30,6 +30,8 @@ lazy_static = "1.4.0"
 atty = "0.2.14"
 tree-sitter = "0.19.5"
 libc = "0.2.99"
+log = "0.4.14"
+pretty_env_logger = "0.4.0"
 
 [dev-dependencies]
 pretty_assertions = "0.6.1"

src/dijkstra.rs

@@ -230,15 +230,24 @@ fn shortest_path(start: Vertex) -> Vec<(Edge, Vertex)> {
         }
     }
 
+    info!(
+        "Found predecessors for {} syntax nodes.",
+        predecessors.len()
+    );
     let mut current = end;
-    let mut res: Vec<(Edge, Vertex)> = vec![];
+
+    let mut route: Vec<(Edge, Vertex)> = vec![];
+    let mut cost = 0;
     while let Some(Some((node, edge))) = predecessors.remove(&current) {
-        res.push((edge, node.clone()));
+        route.push((edge, node.clone()));
+        cost += edge.cost();
+
         current = node;
     }
+    info!("Found found a path of {} with cost {}.", route.len(), cost);
 
-    res.reverse();
-    res
+    route.reverse();
+    route
 }
 
 const NOVEL_TREE_THRESHOLD: u64 = 20;

src/main.rs

@@ -23,6 +23,10 @@ use crate::lines::{join_overlapping, visible_groups, MaxLine};
 use crate::syntax::{change_positions, init_info, matching_lines};
 use crate::tree_sitter_parser as tsp;
 
+extern crate pretty_env_logger;
+#[macro_use]
+extern crate log;
+
 fn configure_color() {
     if atty::is(Stream::Stdout) || env::var("GIT_PAGER_IN_USE").is_ok() {
         // Always enable colour if stdout is a TTY or if the git pager is active.
@@ -147,6 +151,8 @@ fn reset_sigpipe() {
 }
 
 fn main() {
+    pretty_env_logger::init();
+
     reset_sigpipe();
     configure_color();
     let arena = Arena::new();