Merge pull request #44 from Joannis/jo/http-fields-dictionary-literal

Optimise initialization of HTTPFields through Dictionary Literal

Author: guoye-zhang

Benchmarks/.gitignore

@@ -0,0 +1,8 @@
+.DS_Store
+/.build
+/Packages
+xcuserdata/
+DerivedData/
+.swiftpm/configuration/registries.json
+.swiftpm/xcode/package.xcworkspace/contents.xcworkspacedata
+.netrc

Benchmarks/Benchmarks/HTTPFieldsBenchmarks/Benchmarks.swift

@@ -0,0 +1,16 @@
+import HTTPTypes
+import Benchmark
+
+let benchmarks = {
+    Benchmark(
+        "Initialize HTTPFields from Dictionary Literal"
+    ) { benchmark in
+        let fiels: HTTPFields = [
+            .contentType: "application/json",
+            .contentLength: "42",
+            .connection: "keep-alive",
+            .accept: "application/json",
+            .acceptEncoding: "gzip, deflate, br",
+        ]
+    }
+}

Benchmarks/Package.swift

@@ -0,0 +1,27 @@
+// swift-tools-version: 5.7.1
+
+import PackageDescription
+
+let package = Package(
+    name: "Benchmarks",
+    platforms: [
+        .macOS(.v13)
+    ],
+    dependencies: [
+        .package(path: "../"),
+        .package(url: "https://github.com/ordo-one/package-benchmark.git", from: "1.22.1"),
+    ],
+    targets: [
+        .executableTarget(
+            name: "Benchmarks",
+            dependencies: [
+                .product(name: "Benchmark", package: "package-benchmark"),
+                .product(name: "HTTPTypes", package: "swift-http-types"),
+            ],
+            path: "Benchmarks/HTTPFieldsBenchmarks",
+            plugins: [
+                .plugin(name: "BenchmarkPlugin", package: "package-benchmark")
+            ]
+        ),
+    ]
+)

Sources/HTTPTypes/HTTPFields.swift

@@ -280,6 +280,7 @@ public struct HTTPFields: Sendable, Hashable {
 
 extension HTTPFields: ExpressibleByDictionaryLiteral {
     public init(dictionaryLiteral elements: (HTTPField.Name, String)...) {
+        self.reserveCapacity(elements.count)
         for (name, value) in elements {
             precondition(!name.isPseudo, "Pseudo header field \"\(name)\" disallowed")
             self._storage.append(field: HTTPField(name: name, value: value))