1 files changed, 69 insertions, 68 deletions

diff --git a/src/core/lib/transport/metadata.h b/src/core/lib/transport/metadata.h
index 991eee96f1..f4ba86c854 100644
--- a/src/core/lib/transport/metadata.h
+++ b/src/core/lib/transport/metadata.h
@@ -34,6 +34,7 @@
 #ifndef GRPC_CORE_LIB_TRANSPORT_METADATA_H
 #define GRPC_CORE_LIB_TRANSPORT_METADATA_H
 
+#include <grpc/grpc.h>
 #include <grpc/slice.h>
 #include <grpc/support/useful.h>
 
@@ -74,110 +75,110 @@ extern "C" {
    declared here - in which case those functions are effectively no-ops. */
 
 /* Forward declarations */
-typedef struct grpc_mdstr grpc_mdstr;
 typedef struct grpc_mdelem grpc_mdelem;
 
-/* if changing this, make identical changes in internal_string in metadata.c */
-struct grpc_mdstr {
-  const grpc_slice slice;
-  const uint32_t hash;
+/* if changing this, make identical changes in:
+   - interned_metadata, allocated_metadata in metadata.c
+   - grpc_metadata in grpc_types.h */
+typedef struct grpc_mdelem_data {
+  const grpc_slice key;
+  const grpc_slice value;
   /* there is a private part to this in metadata.c */
-};
+} grpc_mdelem_data;
+
+/* GRPC_MDELEM_STORAGE_* enum values that can be treated as interned always have
+   this bit set in their integer value */
+#define GRPC_MDELEM_STORAGE_INTERNED_BIT 1
+
+typedef enum {
+  /* memory pointed to by grpc_mdelem::payload is owned by an external system */
+  GRPC_MDELEM_STORAGE_EXTERNAL = 0,
+  /* memory pointed to by grpc_mdelem::payload is interned by the metadata
+     system */
+  GRPC_MDELEM_STORAGE_INTERNED = GRPC_MDELEM_STORAGE_INTERNED_BIT,
+  /* memory pointed to by grpc_mdelem::payload is allocated by the metadata
+     system */
+  GRPC_MDELEM_STORAGE_ALLOCATED = 2,
+  /* memory is in the static metadata table */
+  GRPC_MDELEM_STORAGE_STATIC = 2 | GRPC_MDELEM_STORAGE_INTERNED_BIT,
+} grpc_mdelem_data_storage;
 
-/* if changing this, make identical changes in internal_metadata in
-   metadata.c */
 struct grpc_mdelem {
-  grpc_mdstr *const key;
-  grpc_mdstr *const value;
-  /* there is a private part to this in metadata.c */
+  /* a grpc_mdelem_data* generally, with the two lower bits signalling memory
+     ownership as per grpc_mdelem_data_storage */
+  uintptr_t payload;
 };
 
-void grpc_test_only_set_metadata_hash_seed(uint32_t seed);
-
-/* Constructors for grpc_mdstr instances; take a variety of data types that
-   clients may have handy */
-grpc_mdstr *grpc_mdstr_from_string(const char *str);
-/* Unrefs the slice. */
-grpc_mdstr *grpc_mdstr_from_slice(grpc_exec_ctx *exec_ctx, grpc_slice slice);
-grpc_mdstr *grpc_mdstr_from_buffer(const uint8_t *str, size_t length);
-
-/* Returns a borrowed slice from the mdstr with its contents base64 encoded
-   and huffman compressed */
-grpc_slice grpc_mdstr_as_base64_encoded_and_huffman_compressed(grpc_mdstr *str);
-
-/* Constructors for grpc_mdelem instances; take a variety of data types that
-   clients may have handy */
-grpc_mdelem *grpc_mdelem_from_metadata_strings(grpc_exec_ctx *exec_ctx,
-                                               grpc_mdstr *key,
-                                               grpc_mdstr *value);
-grpc_mdelem *grpc_mdelem_from_strings(grpc_exec_ctx *exec_ctx, const char *key,
-                                      const char *value);
+#define GRPC_MDELEM_DATA(md) \
+  ((grpc_mdelem_data *)((md).payload & ~(uintptr_t)3))
+#define GRPC_MDELEM_STORAGE(md) \
+  ((grpc_mdelem_data_storage)((md).payload & (uintptr_t)3))
+#define GRPC_MAKE_MDELEM(data, storage) \
+  ((grpc_mdelem){((uintptr_t)(data)) | ((uintptr_t)storage)})
+#define GRPC_MDELEM_IS_INTERNED(md)          \
+  ((grpc_mdelem_data_storage)((md).payload & \
+                              (uintptr_t)GRPC_MDELEM_STORAGE_INTERNED_BIT))
+
 /* Unrefs the slices. */
-grpc_mdelem *grpc_mdelem_from_slices(grpc_exec_ctx *exec_ctx, grpc_slice key,
-                                     grpc_slice value);
-grpc_mdelem *grpc_mdelem_from_string_and_buffer(grpc_exec_ctx *exec_ctx,
-                                                const char *key,
-                                                const uint8_t *value,
-                                                size_t value_length);
+grpc_mdelem grpc_mdelem_from_slices(grpc_exec_ctx *exec_ctx, grpc_slice key,
+                                    grpc_slice value);
+
+/* Cheaply convert a grpc_metadata to a grpc_mdelem; may use the grpc_metadata
+   object as backing storage (so lifetimes should align) */
+grpc_mdelem grpc_mdelem_from_grpc_metadata(grpc_exec_ctx *exec_ctx,
+                                           grpc_metadata *metadata);
 
-size_t grpc_mdelem_get_size_in_hpack_table(grpc_mdelem *elem);
+/* Does not unref the slices; if a new non-interned mdelem is needed, allocates
+   one if compatible_external_backing_store is NULL, or uses
+   compatible_external_backing_store if it is non-NULL (in which case it's the
+   users responsibility to ensure that it outlives usage) */
+grpc_mdelem grpc_mdelem_create(
+    grpc_exec_ctx *exec_ctx, grpc_slice key, grpc_slice value,
+    grpc_mdelem_data *compatible_external_backing_store);
+
+bool grpc_mdelem_eq(grpc_mdelem a, grpc_mdelem b);
+
+size_t grpc_mdelem_get_size_in_hpack_table(grpc_mdelem elem);
 
 /* Mutator and accessor for grpc_mdelem user data. The destructor function
    is used as a type tag and is checked during user_data fetch. */
-void *grpc_mdelem_get_user_data(grpc_mdelem *md,
+void *grpc_mdelem_get_user_data(grpc_mdelem md,
                                 void (*if_destroy_func)(void *));
-void *grpc_mdelem_set_user_data(grpc_mdelem *md, void (*destroy_func)(void *),
+void *grpc_mdelem_set_user_data(grpc_mdelem md, void (*destroy_func)(void *),
                                 void *user_data);
 
 /* Reference counting */
 //#define GRPC_METADATA_REFCOUNT_DEBUG
 #ifdef GRPC_METADATA_REFCOUNT_DEBUG
-#define GRPC_MDSTR_REF(s) grpc_mdstr_ref((s), __FILE__, __LINE__)
-#define GRPC_MDSTR_UNREF(exec_ctx, s) \
-  grpc_mdstr_unref((exec_ctx), (s), __FILE__, __LINE__)
 #define GRPC_MDELEM_REF(s) grpc_mdelem_ref((s), __FILE__, __LINE__)
 #define GRPC_MDELEM_UNREF(exec_ctx, s) \
   grpc_mdelem_unref((exec_ctx), (s), __FILE__, __LINE__)
-grpc_mdstr *grpc_mdstr_ref(grpc_mdstr *s, const char *file, int line);
-void grpc_mdstr_unref(grpc_exec_ctx *exec_ctx, grpc_mdstr *s, const char *file,
-                      int line);
-grpc_mdelem *grpc_mdelem_ref(grpc_mdelem *md, const char *file, int line);
-void grpc_mdelem_unref(grpc_exec_ctx *exec_ctx, grpc_mdelem *md,
+grpc_mdelem grpc_mdelem_ref(grpc_mdelem md, const char *file, int line);
+void grpc_mdelem_unref(grpc_exec_ctx *exec_ctx, grpc_mdelem md,
                        const char *file, int line);
 #else
-#define GRPC_MDSTR_REF(s) grpc_mdstr_ref((s))
-#define GRPC_MDSTR_UNREF(exec_ctx, s) grpc_mdstr_unref((exec_ctx), (s))
 #define GRPC_MDELEM_REF(s) grpc_mdelem_ref((s))
 #define GRPC_MDELEM_UNREF(exec_ctx, s) grpc_mdelem_unref((exec_ctx), (s))
-grpc_mdstr *grpc_mdstr_ref(grpc_mdstr *s);
-void grpc_mdstr_unref(grpc_exec_ctx *exec_ctx, grpc_mdstr *s);
-grpc_mdelem *grpc_mdelem_ref(grpc_mdelem *md);
-void grpc_mdelem_unref(grpc_exec_ctx *exec_ctx, grpc_mdelem *md);
+grpc_mdelem grpc_mdelem_ref(grpc_mdelem md);
+void grpc_mdelem_unref(grpc_exec_ctx *exec_ctx, grpc_mdelem md);
 #endif
 
-/* Recover a char* from a grpc_mdstr. The returned string is null terminated.
-   Does not promise that the returned string has no embedded nulls however. */
-const char *grpc_mdstr_as_c_string(const grpc_mdstr *s);
+#define GRPC_MDKEY(md) (GRPC_MDELEM_DATA(md)->key)
+#define GRPC_MDVALUE(md) (GRPC_MDELEM_DATA(md)->value)
 
-#define GRPC_MDSTR_LENGTH(s) (GRPC_SLICE_LENGTH(s->slice))
+#define GRPC_MDNULL GRPC_MAKE_MDELEM(NULL, GRPC_MDELEM_STORAGE_EXTERNAL)
+#define GRPC_MDISNULL(md) (GRPC_MDELEM_DATA(md) == NULL)
 
 /* We add 32 bytes of padding as per RFC-7540 section 6.5.2. */
-#define GRPC_MDELEM_LENGTH(e) \
-  (GRPC_MDSTR_LENGTH((e)->key) + GRPC_MDSTR_LENGTH((e)->value) + 32)
-
-int grpc_mdstr_is_legal_header(grpc_mdstr *s);
-int grpc_mdstr_is_legal_nonbin_header(grpc_mdstr *s);
-int grpc_mdstr_is_bin_suffixed(grpc_mdstr *s);
+#define GRPC_MDELEM_LENGTH(e)                                                  \
+  (GRPC_SLICE_LENGTH(GRPC_MDKEY((e))) + GRPC_SLICE_LENGTH(GRPC_MDVALUE((e))) + \
+   32)
 
 #define GRPC_MDSTR_KV_HASH(k_hash, v_hash) (GPR_ROTL((k_hash), 2) ^ (v_hash))
 
 void grpc_mdctx_global_init(void);
 void grpc_mdctx_global_shutdown(grpc_exec_ctx *exec_ctx);
 
-/* Implementation provided by chttp2_transport */
-extern grpc_slice (*grpc_chttp2_base64_encode_and_huffman_compress)(
-    grpc_slice input);
-
 #ifdef __cplusplus
 }
 #endif