From 0196b5e1039224d3b55699cd054e14f852036fb3 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Pawe=C5=82=20Zmarz=C5=82y?= <pawo2500@gmail.com>
Date: Sat, 14 Sep 2019 13:35:11 +0200
Subject: [PATCH 1/2] Add optional caching

---
 markup-proc-macro/Cargo.toml     |  5 +++++
 markup-proc-macro/src/caching.rs | 33 ++++++++++++++++++++++++++++++++
 markup-proc-macro/src/lib.rs     | 11 ++++++++---
 markup/Cargo.toml                |  3 +++
 4 files changed, 49 insertions(+), 3 deletions(-)
 create mode 100644 markup-proc-macro/src/caching.rs

diff --git a/markup-proc-macro/Cargo.toml b/markup-proc-macro/Cargo.toml
index 7a39e27..45cc095 100644
--- a/markup-proc-macro/Cargo.toml
+++ b/markup-proc-macro/Cargo.toml
@@ -16,3 +16,8 @@ proc-macro = true
 proc-macro2 = "1.0.3"
 quote = "1.0.2"
 syn = { version = "1.0.5", features = ["extra-traits", "full"] }
+sha2 = { version = "0.8", optional = true }
+dirs = { version = "2.0.2", optional = true }
+
+[features]
+caching = ["sha2", "dirs"]
diff --git a/markup-proc-macro/src/caching.rs b/markup-proc-macro/src/caching.rs
new file mode 100644
index 0000000..d6bb4e2
--- /dev/null
+++ b/markup-proc-macro/src/caching.rs
@@ -0,0 +1,33 @@
+use proc_macro::TokenStream;
+
+#[cfg(not(feature = "caching"))]
+pub fn cached(tokens: TokenStream, f: impl FnOnce(TokenStream) -> TokenStream) -> TokenStream {
+    f(tokens)
+}
+
+#[cfg(feature = "caching")]
+pub fn cached(tokens: TokenStream, f: impl FnOnce(TokenStream) -> TokenStream) -> TokenStream {
+    use sha2::{Digest, Sha256};
+    use std::fs;
+
+    let dir = dirs::cache_dir().unwrap().join("markup-rs");
+    let _ = fs::create_dir(&dir);
+
+    let input = tokens.to_string();
+    let mut hasher = Sha256::new();
+    hasher.input(input);
+    let hash = hasher.result();
+    let path = dir.join(format!("{:x}", hash));
+
+    if let Ok(cached) = fs::read_to_string(&path) {
+        if let Ok(cached) = cached.parse() {
+            return cached;
+        }
+    }
+
+    let output = f(tokens);
+    if fs::write(&path, output.to_string()).is_err() {
+        eprintln!("warning: cannot write to cache dir");
+    }
+    output
+}
diff --git a/markup-proc-macro/src/lib.rs b/markup-proc-macro/src/lib.rs
index 045c574..24562ea 100644
--- a/markup-proc-macro/src/lib.rs
+++ b/markup-proc-macro/src/lib.rs
@@ -2,11 +2,16 @@
 extern crate proc_macro;
 
 mod ast;
+mod caching;
 mod generate;
 mod parse;
 
+use proc_macro::TokenStream;
+
 #[proc_macro]
-pub fn define(tokens: proc_macro::TokenStream) -> proc_macro::TokenStream {
-    let structs = syn::parse_macro_input!(tokens as parse::Many<ast::Struct>).0;
-    quote::quote!( #(#structs)* ).into()
+pub fn define(tokens: TokenStream) -> TokenStream {
+    caching::cached(tokens, |tokens| {
+        let structs = syn::parse_macro_input!(tokens as parse::Many<ast::Struct>).0;
+        quote::quote!( #(#structs)* ).into()
+    })
 }
diff --git a/markup/Cargo.toml b/markup/Cargo.toml
index 9865719..9511ee4 100644
--- a/markup/Cargo.toml
+++ b/markup/Cargo.toml
@@ -14,3 +14,6 @@ categories = ["template-engine"]
 
 [dependencies]
 markup-proc-macro = { path = "../markup-proc-macro", version = "0.4.0" }
+
+[features]
+caching = ["markup-proc-macro/caching"]

From a4e5034ba95eeb26c68dc3942a1936608d31cb1f Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Pawe=C5=82=20Zmarz=C5=82y?= <pawo2500@gmail.com>
Date: Sun, 15 Sep 2019 07:28:12 +0200
Subject: [PATCH 2/2] Use separate cache dirs for different crate versions

---
 markup-proc-macro/Cargo.toml     | 3 ++-
 markup-proc-macro/src/caching.rs | 2 ++
 2 files changed, 4 insertions(+), 1 deletion(-)

diff --git a/markup-proc-macro/Cargo.toml b/markup-proc-macro/Cargo.toml
index 45cc095..af288a9 100644
--- a/markup-proc-macro/Cargo.toml
+++ b/markup-proc-macro/Cargo.toml
@@ -18,6 +18,7 @@ quote = "1.0.2"
 syn = { version = "1.0.5", features = ["extra-traits", "full"] }
 sha2 = { version = "0.8", optional = true }
 dirs = { version = "2.0.2", optional = true }
+version = { version = "3.0.0", optional = true }
 
 [features]
-caching = ["sha2", "dirs"]
+caching = ["sha2", "dirs", "version"]
diff --git a/markup-proc-macro/src/caching.rs b/markup-proc-macro/src/caching.rs
index d6bb4e2..22fc9d9 100644
--- a/markup-proc-macro/src/caching.rs
+++ b/markup-proc-macro/src/caching.rs
@@ -12,6 +12,8 @@ pub fn cached(tokens: TokenStream, f: impl FnOnce(TokenStream) -> TokenStream) -
 
     let dir = dirs::cache_dir().unwrap().join("markup-rs");
     let _ = fs::create_dir(&dir);
+    let dir = dir.join(version::version!().to_string());
+    let _ = fs::create_dir(&dir);
 
     let input = tokens.to_string();
     let mut hasher = Sha256::new();