Expose the name of every symbol in the index

Sources/IndexStoreDB/IndexStoreDB.swift

@@ -187,6 +187,27 @@ public final class IndexStoreDB {
     }
     return result
   }
+
+  /// Iterates over the name of every symbol in the index.
+  ///
+  /// - Parameter body: A closure to be called for each symbol. The closure should return true to
+  /// continue iterating.
+  @discardableResult
+  public func forEachSymbolName(body: @escaping (String) -> Bool) -> Bool {
+    return indexstoredb_index_symbol_names(impl) { name in
+      body(String(cString: name))
+    }
+  }
+
+  /// Returns an array with every symbol name in the index.
+  public func allSymbolNames() -> [String] {
+    var result: [String] = []
+    forEachSymbolName { name in
+      result.append(name)
+      return true
+    }
+    return result
+  }
 }
 
 public protocol IndexStoreLibraryProvider {

Tests/IndexStoreDBTests/IndexTests.swift

@@ -279,4 +279,14 @@ final class IndexTests: XCTestCase {
     XCTAssertEqual(mainFiles(unknown, true), [])
     XCTAssertEqual(mainFiles(unknown, false), [])
   }
+
+  func testAllSymbolNames() throws {
+    guard let ws = try staticTibsTestWorkspace(name: "proj1") else { return }
+    try ws.buildAndIndex()
+    let index = ws.index
+
+    let expectedSymbolNames = ["a()", "b()", "c()"]
+
+    XCTAssertEqual(index.allSymbolNames(), expectedSymbolNames)
+  }
 }

Tests/IndexStoreDBTests/XCTestManifests.swift

@@ -16,6 +16,7 @@ extension IndexTests {
     //   `swift test --generate-linuxmain`
     // to regenerate.
     static let __allTests__IndexTests = [
+        ("testAllSymbolNames", testAllSymbolNames),
         ("testBasic", testBasic),
         ("testDelegate", testDelegate),
         ("testEditsSimple", testEditsSimple),