fuzzing: progress towards web UI

* libfuzzer: close file after mmap
* fuzzer/main.js: connect with EventSource and debug dump the messages.
  currently this prints how many fuzzer runs have been attempted to
  console.log.
* extract some `std.debug.Info` logic into `std.debug.Coverage`.
  Prepares for consolidation across multiple different executables which
  share source files, and makes it possible to send all the
  PC/SourceLocation mapping data with 4 memcpy'd arrays.
* std.Build.Fuzz:
  - spawn a thread to watch the message queue and signal event
    subscribers.
  - track coverage map data
  - respond to /events URL with EventSource messages on a timer

1 files changed, 10 insertions, 3 deletions

diff --git a/lib/fuzzer/main.js b/lib/fuzzer/main.js
index 71e6b5fa54..872ac3d4b5 100644
--- a/lib/fuzzer/main.js
+++ b/lib/fuzzer/main.js
@@ -12,6 +12,9 @@
     const text_decoder = new TextDecoder();
     const text_encoder = new TextEncoder();
 
+    const eventSource = new EventSource("events");
+    eventSource.addEventListener('message', onMessage, false);
+
     WebAssembly.instantiateStreaming(wasm_promise, {
       js: {
         log: function(ptr, len) {
@@ -38,11 +41,15 @@
       });
     });
 
+    function onMessage(e) {
+      console.log("Message", e.data);
+    }
+
     function render() {
-        domSectSource.classList.add("hidden");
+      domSectSource.classList.add("hidden");
 
-        // TODO this is temporary debugging data
-        renderSource("/home/andy/dev/zig/lib/std/zig/tokenizer.zig");
+      // TODO this is temporary debugging data
+      renderSource("/home/andy/dev/zig/lib/std/zig/tokenizer.zig");
     }
 
     function renderSource(path) {