Merge pull request #138 from wesleywiser/multiple_args

Add a way to create an `EventId` with multiple arguments

Author: wesleywiser

measureme/Cargo.toml

@@ -13,5 +13,6 @@ repository = "https://github.com/rust-lang/measureme"
 travis-ci = { repository = "rust-lang/measureme" }
 
 [dependencies]
-rustc-hash = "1.0.1"
 parking_lot = "0.11.0"
+rustc-hash = "1.0.1"
+smallvec = "1.0"

measureme/src/event_id.rs

@@ -1,3 +1,5 @@
+use smallvec::SmallVec;
+
 use crate::{Profiler, StringComponent, StringId};
 
 /// Event IDs are strings conforming to the following grammar:
@@ -78,4 +80,18 @@ impl<'p> EventIdBuilder<'p> {
             StringComponent::Ref(arg),
         ]))
     }
+
+    pub fn from_label_and_args(&self, label: StringId, args: &[StringId]) -> EventId {
+        // Store up to 7 components on the stack: 1 label + 3 arguments + 3 argument separators
+        let mut parts = SmallVec::<[StringComponent; 7]>::with_capacity(1 + args.len() * 2);
+
+        parts.push(StringComponent::Ref(label));
+
+        for arg in args {
+            parts.push(StringComponent::Value(SEPARATOR_BYTE));
+            parts.push(StringComponent::Ref(*arg));
+        }
+
+        EventId(self.profiler.alloc_string(&parts[..]))
+    }
 }