6 files changed, 36 insertions, 26 deletions
diff --git a/absl/strings/BUILD.bazel b/absl/strings/BUILD.bazel
index 4ee5a2ca..8aecbe59 100644
--- a/absl/strings/BUILD.bazel
+++ b/absl/strings/BUILD.bazel
@@ -310,6 +310,7 @@ cc_test(
     deps = [
         ":cord",
         ":cord_test_helpers",
+        ":str_format",
         ":strings",
         "//absl/base",
         "//absl/base:config",
@@ -667,7 +668,6 @@ cc_test(
     copts = ABSL_TEST_COPTS,
     visibility = ["//visibility:private"],
     deps = [
-        ":cord",
         ":str_format",
         ":str_format_internal",
         ":strings",
diff --git a/absl/strings/CMakeLists.txt b/absl/strings/CMakeLists.txt
index 10213022..b6705ed0 100644
--- a/absl/strings/CMakeLists.txt
+++ b/absl/strings/CMakeLists.txt
@@ -425,7 +425,6 @@ absl_cc_test(
   DEPS
     absl::str_format
     absl::str_format_internal
-    absl::cord
     absl::strings
     gmock_main
 )
@@ -581,6 +580,7 @@ absl_cc_test(
     ${ABSL_TEST_COPTS}
   DEPS
     absl::cord
+    absl::str_format
     absl::strings
     absl::base
     absl::config
diff --git a/absl/strings/cord.h b/absl/strings/cord.h
index 2d92f6d6..9d99b2af 100644
--- a/absl/strings/cord.h
+++ b/absl/strings/cord.h
@@ -90,10 +90,6 @@ class CordTestPeer;
 template <typename Releaser>
 Cord MakeCordFromExternal(absl::string_view, Releaser&&);
 void CopyCordToString(const Cord& src, std::string* dst);
-namespace hash_internal {
-template <typename H>
-H HashFragmentedCord(H, const Cord&);
-}
 
 // Cord
 //
@@ -615,10 +611,22 @@ class Cord {
   // If the cord was already flat, the contents are not modified.
   absl::string_view Flatten();
 
+  // Support absl::Cord as a sink object for absl::Format().
+  friend void AbslFormatFlush(absl::Cord* cord, absl::string_view part) {
+    cord->Append(part);
+  }
+
+  template <typename H>
+  friend H AbslHashValue(H hash_state, const absl::Cord& c) {
+    absl::optional<absl::string_view> maybe_flat = c.TryFlat();
+    if (maybe_flat.has_value()) {
+      return H::combine(std::move(hash_state), *maybe_flat);
+    }
+    return c.HashFragmented(std::move(hash_state));
+  }
+
  private:
   friend class CordTestPeer;
-  template <typename H>
-  friend H absl::hash_internal::HashFragmentedCord(H, const Cord&);
   friend bool operator==(const Cord& lhs, const Cord& rhs);
   friend bool operator==(const Cord& lhs, absl::string_view rhs);
 
@@ -763,6 +771,17 @@ class Cord {
   // Helper for Append()
   template <typename C>
   void AppendImpl(C&& src);
+
+  // Helper for AbslHashValue()
+  template <typename H>
+  H HashFragmented(H hash_state) const {
+    typename H::AbslInternalPiecewiseCombiner combiner;
+    ForEachChunk([&combiner, &hash_state](absl::string_view chunk) {
+      hash_state = combiner.add_buffer(std::move(hash_state), chunk.data(),
+                                       chunk.size());
+    });
+    return H::combine(combiner.finalize(std::move(hash_state)), size());
+  }
 };
 
 ABSL_NAMESPACE_END
diff --git a/absl/strings/cord_test.cc b/absl/strings/cord_test.cc
index 49178498..336cedde 100644
--- a/absl/strings/cord_test.cc
+++ b/absl/strings/cord_test.cc
@@ -22,6 +22,7 @@
 #include "absl/container/fixed_array.h"
 #include "absl/strings/cord_test_helpers.h"
 #include "absl/strings/str_cat.h"
+#include "absl/strings/str_format.h"
 #include "absl/strings/string_view.h"
 
 typedef std::mt19937_64 RandomEngine;
@@ -1582,6 +1583,14 @@ TEST(Cord, SmallBufferAssignFromOwnData) {
   }
 }
 
+TEST(Cord, Format) {
+  absl::Cord c;
+  absl::Format(&c, "There were %04d little %s.", 3, "pigs");
+  EXPECT_EQ(c, "There were 0003 little pigs.");
+  absl::Format(&c, "And %-3llx bad wolf!", 1);
+  EXPECT_EQ(c, "There were 0003 little pigs.And 1   bad wolf!");
+}
+
 TEST(CordDeathTest, Hardening) {
   absl::Cord cord("hello");
   // These statement should abort the program in all builds modes.
diff --git a/absl/strings/internal/str_format/extension_test.cc b/absl/strings/internal/str_format/extension_test.cc
index dc5576b6..561eaa36 100644
--- a/absl/strings/internal/str_format/extension_test.cc
+++ b/absl/strings/internal/str_format/extension_test.cc
@@ -19,7 +19,6 @@
 #include <random>
 #include <string>
 
-#include "absl/strings/cord.h"
 #include "gtest/gtest.h"
 #include "absl/strings/str_format.h"
 #include "absl/strings/string_view.h"
@@ -82,14 +81,6 @@ TEST(FormatExtensionTest, SinkAppendChars) {
   }
 }
 
-TEST(FormatExtensionTest, CordSink) {
-  absl::Cord c;
-  absl::Format(&c, "There were %04d little %s.", 3, "pigs");
-  EXPECT_EQ(c, "There were 0003 little pigs.");
-  absl::Format(&c, "And %-3llx bad wolf!", 1);
-  EXPECT_EQ(c, "There were 0003 little pigs.And 1   bad wolf!");
-}
-
 TEST(FormatExtensionTest, CustomSink) {
   my_namespace::UserDefinedType sink;
   absl::Format(&sink, "There were %04d little %s.", 3, "pigs");
diff --git a/absl/strings/internal/str_format/output.h b/absl/strings/internal/str_format/output.h
index c3168d20..8030dae0 100644
--- a/absl/strings/internal/str_format/output.h
+++ b/absl/strings/internal/str_format/output.h
@@ -30,9 +30,6 @@
 
 namespace absl {
 ABSL_NAMESPACE_BEGIN
-
-class Cord;
-
 namespace str_format_internal {
 
 // RawSink implementation that writes into a char* buffer.
@@ -77,12 +74,6 @@ inline void AbslFormatFlush(std::ostream* out, string_view s) {
   out->write(s.data(), s.size());
 }
 
-template <class AbslCord, typename = typename std::enable_if<
-                              std::is_same<AbslCord, absl::Cord>::value>::type>
-inline void AbslFormatFlush(AbslCord* out, string_view s) {
-  out->Append(s);
-}
-
 inline void AbslFormatFlush(FILERawSink* sink, string_view v) {
   sink->Write(v);
 }