feat(hydroflow_lang): open mermaid/dot graph in browser (#923)

* `HydroflowGraph::open_mermaid()` opens https://mermaid.live/
* `HydroflowGraph::open_dot()` opens https://dreampuf.github.io/GraphvizOnline/

Behind a new `hydroflow/debugging`/`hydroflow_lang/debugging` feature
gate.

hydroflow/Cargo.toml

@@ -8,14 +8,15 @@ documentation = "https://docs.rs/hydroflow/"
 description = "Hydro's low-level dataflow runtime and IR"
 
 [features]
-default = [ "macros" , "nightly" ]
+default = [ "macros" , "nightly", "debugging" ]
 
 nightly = [ "hydroflow_macro", "hydroflow_macro/diagnostics" ]
 macros = [ "hydroflow_macro", "hydroflow_datalog" ]
 hydroflow_macro = [ "dep:hydroflow_macro" ]
 hydroflow_datalog = [ "dep:hydroflow_datalog" ]
 cli_integration = [ "dep:hydroflow_cli_integration" ]
 python = [ "dep:pyo3" ]
+debugging = [ "hydroflow_lang/debugging" ]
 
 [[example]]
 name = "kvs_bench"

hydroflow_lang/Cargo.toml

@@ -10,9 +10,11 @@ description = "Hydroflow's Surface Syntax implementation"
 [features]
 default = []
 diagnostics = []
+debugging = [ "dep:data-encoding", "dep:webbrowser" ]
 
 [dependencies]
 auto_impl = "1.0.1"
+data-encoding = { version = "2.4.0", optional = true }
 itertools = "0.10" # TODO(mingwei): remove when `iter_intersperse` is stabilized.
 prettyplease = { version = "0.2.0", features = [ "verbatim" ] }
 proc-macro2 = { version = "1.0.63", features = ["span-locations"] }
@@ -22,6 +24,7 @@ serde = "1.0.1"
 serde_json = "1.0.8"
 slotmap = { version = "1.0.6", features = ["serde"] }
 syn = { version = "2.0.0", features = [ "extra-traits", "full", "parsing" ] }
+webbrowser = { version = "0.8.11", optional = true }
 
 [dev-dependencies]
 

hydroflow_lang/src/graph/hydroflow_graph_debugging.rs

@@ -0,0 +1,39 @@
+#![cfg(feature = "debugging")]
+
+use std::fmt::Write;
+use std::io::Result;
+
+use super::HydroflowGraph;
+
+impl HydroflowGraph {
+    /// Opens this as a mermaid graph in the [mermaid.live](https://mermaid.live) browser editor.
+    pub fn open_mermaid(&self) -> Result<()> {
+        let mermaid_src = self.to_mermaid();
+        let state = serde_json::json!({
+            "code": mermaid_src,
+            "mermaid": serde_json::json!({
+                "theme": "default"
+            }),
+            "autoSync": true,
+            "updateDiagram": true
+        });
+        let state_json = serde_json::to_vec(&state)?;
+        let state_base64 = data_encoding::BASE64URL.encode(&state_json);
+        webbrowser::open(&format!(
+            "https://mermaid.live/edit#base64:{}",
+            state_base64
+        ))
+    }
+
+    /// Opens this as dot/graphviz graph in the [Graphviz Online](https://dreampuf.github.io/GraphvizOnline/#)
+    /// browser editor.
+    pub fn open_dot(&self) -> Result<()> {
+        let dot_src = self.to_dot();
+        let mut url = "https://dreampuf.github.io/GraphvizOnline/#".to_owned();
+        for byte in dot_src.bytes() {
+            // Lazy percent encoding: https://en.wikipedia.org/wiki/Percent-encoding
+            write!(url, "%{:02x}", byte).unwrap();
+        }
+        webbrowser::open(&url)
+    }
+}

hydroflow_lang/src/graph/mod.rs

@@ -23,6 +23,7 @@ mod flat_to_partitioned;
 mod flow_props;
 mod graph_write;
 mod hydroflow_graph;
+mod hydroflow_graph_debugging;
 
 use std::fmt::Display;
 use std::path::PathBuf;