1 files changed, 313 insertions, 0 deletions
diff --git a/src/core/lib/transport/metadata_batch.cc b/src/core/lib/transport/metadata_batch.cc
new file mode 100644
index 0000000000..2df9c9189c
--- /dev/null
+++ b/src/core/lib/transport/metadata_batch.cc
@@ -0,0 +1,313 @@
+/*
+ *
+ * Copyright 2015 gRPC authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ */
+
+#include "src/core/lib/transport/metadata_batch.h"
+
+#include <stdbool.h>
+#include <string.h>
+
+#include <grpc/support/alloc.h>
+#include <grpc/support/log.h>
+
+#include "src/core/lib/profiling/timers.h"
+#include "src/core/lib/slice/slice_internal.h"
+#include "src/core/lib/slice/slice_string_helpers.h"
+
+static void assert_valid_list(grpc_mdelem_list *list) {
+#ifndef NDEBUG
+  grpc_linked_mdelem *l;
+
+  GPR_ASSERT((list->head == NULL) == (list->tail == NULL));
+  if (!list->head) return;
+  GPR_ASSERT(list->head->prev == NULL);
+  GPR_ASSERT(list->tail->next == NULL);
+  GPR_ASSERT((list->head == list->tail) == (list->head->next == NULL));
+
+  size_t verified_count = 0;
+  for (l = list->head; l; l = l->next) {
+    GPR_ASSERT(!GRPC_MDISNULL(l->md));
+    GPR_ASSERT((l->prev == NULL) == (l == list->head));
+    GPR_ASSERT((l->next == NULL) == (l == list->tail));
+    if (l->next) GPR_ASSERT(l->next->prev == l);
+    if (l->prev) GPR_ASSERT(l->prev->next == l);
+    verified_count++;
+  }
+  GPR_ASSERT(list->count == verified_count);
+#endif /* NDEBUG */
+}
+
+static void assert_valid_callouts(grpc_exec_ctx *exec_ctx,
+                                  grpc_metadata_batch *batch) {
+#ifndef NDEBUG
+  for (grpc_linked_mdelem *l = batch->list.head; l != NULL; l = l->next) {
+    grpc_slice key_interned = grpc_slice_intern(GRPC_MDKEY(l->md));
+    grpc_metadata_batch_callouts_index callout_idx =
+        GRPC_BATCH_INDEX_OF(key_interned);
+    if (callout_idx != GRPC_BATCH_CALLOUTS_COUNT) {
+      GPR_ASSERT(batch->idx.array[callout_idx] == l);
+    }
+    grpc_slice_unref_internal(exec_ctx, key_interned);
+  }
+#endif
+}
+
+#ifndef NDEBUG
+void grpc_metadata_batch_assert_ok(grpc_metadata_batch *batch) {
+  assert_valid_list(&batch->list);
+}
+#endif /* NDEBUG */
+
+void grpc_metadata_batch_init(grpc_metadata_batch *batch) {
+  memset(batch, 0, sizeof(*batch));
+  batch->deadline = GRPC_MILLIS_INF_FUTURE;
+}
+
+void grpc_metadata_batch_destroy(grpc_exec_ctx *exec_ctx,
+                                 grpc_metadata_batch *batch) {
+  grpc_linked_mdelem *l;
+  for (l = batch->list.head; l; l = l->next) {
+    GRPC_MDELEM_UNREF(exec_ctx, l->md);
+  }
+}
+
+grpc_error *grpc_attach_md_to_error(grpc_error *src, grpc_mdelem md) {
+  grpc_error *out = grpc_error_set_str(
+      grpc_error_set_str(src, GRPC_ERROR_STR_KEY,
+                         grpc_slice_ref_internal(GRPC_MDKEY(md))),
+      GRPC_ERROR_STR_VALUE, grpc_slice_ref_internal(GRPC_MDVALUE(md)));
+  return out;
+}
+
+static grpc_error *maybe_link_callout(grpc_metadata_batch *batch,
+                                      grpc_linked_mdelem *storage)
+    GRPC_MUST_USE_RESULT;
+
+static grpc_error *maybe_link_callout(grpc_metadata_batch *batch,
+                                      grpc_linked_mdelem *storage) {
+  grpc_metadata_batch_callouts_index idx =
+      GRPC_BATCH_INDEX_OF(GRPC_MDKEY(storage->md));
+  if (idx == GRPC_BATCH_CALLOUTS_COUNT) {
+    return GRPC_ERROR_NONE;
+  }
+  if (batch->idx.array[idx] == NULL) {
+    if (grpc_static_callout_is_default[idx]) ++batch->list.default_count;
+    batch->idx.array[idx] = storage;
+    return GRPC_ERROR_NONE;
+  }
+  return grpc_attach_md_to_error(
+      GRPC_ERROR_CREATE_FROM_STATIC_STRING("Unallowed duplicate metadata"),
+      storage->md);
+}
+
+static void maybe_unlink_callout(grpc_metadata_batch *batch,
+                                 grpc_linked_mdelem *storage) {
+  grpc_metadata_batch_callouts_index idx =
+      GRPC_BATCH_INDEX_OF(GRPC_MDKEY(storage->md));
+  if (idx == GRPC_BATCH_CALLOUTS_COUNT) {
+    return;
+  }
+  if (grpc_static_callout_is_default[idx]) --batch->list.default_count;
+  GPR_ASSERT(batch->idx.array[idx] != NULL);
+  batch->idx.array[idx] = NULL;
+}
+
+grpc_error *grpc_metadata_batch_add_head(grpc_exec_ctx *exec_ctx,
+                                         grpc_metadata_batch *batch,
+                                         grpc_linked_mdelem *storage,
+                                         grpc_mdelem elem_to_add) {
+  GPR_ASSERT(!GRPC_MDISNULL(elem_to_add));
+  storage->md = elem_to_add;
+  return grpc_metadata_batch_link_head(exec_ctx, batch, storage);
+}
+
+static void link_head(grpc_mdelem_list *list, grpc_linked_mdelem *storage) {
+  assert_valid_list(list);
+  GPR_ASSERT(!GRPC_MDISNULL(storage->md));
+  storage->prev = NULL;
+  storage->next = list->head;
+  if (list->head != NULL) {
+    list->head->prev = storage;
+  } else {
+    list->tail = storage;
+  }
+  list->head = storage;
+  list->count++;
+  assert_valid_list(list);
+}
+
+grpc_error *grpc_metadata_batch_link_head(grpc_exec_ctx *exec_ctx,
+                                          grpc_metadata_batch *batch,
+                                          grpc_linked_mdelem *storage) {
+  assert_valid_callouts(exec_ctx, batch);
+  grpc_error *err = maybe_link_callout(batch, storage);
+  if (err != GRPC_ERROR_NONE) {
+    assert_valid_callouts(exec_ctx, batch);
+    return err;
+  }
+  link_head(&batch->list, storage);
+  assert_valid_callouts(exec_ctx, batch);
+  return GRPC_ERROR_NONE;
+}
+
+grpc_error *grpc_metadata_batch_add_tail(grpc_exec_ctx *exec_ctx,
+                                         grpc_metadata_batch *batch,
+                                         grpc_linked_mdelem *storage,
+                                         grpc_mdelem elem_to_add) {
+  GPR_ASSERT(!GRPC_MDISNULL(elem_to_add));
+  storage->md = elem_to_add;
+  return grpc_metadata_batch_link_tail(exec_ctx, batch, storage);
+}
+
+static void link_tail(grpc_mdelem_list *list, grpc_linked_mdelem *storage) {
+  assert_valid_list(list);
+  GPR_ASSERT(!GRPC_MDISNULL(storage->md));
+  storage->prev = list->tail;
+  storage->next = NULL;
+  storage->reserved = NULL;
+  if (list->tail != NULL) {
+    list->tail->next = storage;
+  } else {
+    list->head = storage;
+  }
+  list->tail = storage;
+  list->count++;
+  assert_valid_list(list);
+}
+
+grpc_error *grpc_metadata_batch_link_tail(grpc_exec_ctx *exec_ctx,
+                                          grpc_metadata_batch *batch,
+                                          grpc_linked_mdelem *storage) {
+  assert_valid_callouts(exec_ctx, batch);
+  grpc_error *err = maybe_link_callout(batch, storage);
+  if (err != GRPC_ERROR_NONE) {
+    assert_valid_callouts(exec_ctx, batch);
+    return err;
+  }
+  link_tail(&batch->list, storage);
+  assert_valid_callouts(exec_ctx, batch);
+  return GRPC_ERROR_NONE;
+}
+
+static void unlink_storage(grpc_mdelem_list *list,
+                           grpc_linked_mdelem *storage) {
+  assert_valid_list(list);
+  if (storage->prev != NULL) {
+    storage->prev->next = storage->next;
+  } else {
+    list->head = storage->next;
+  }
+  if (storage->next != NULL) {
+    storage->next->prev = storage->prev;
+  } else {
+    list->tail = storage->prev;
+  }
+  list->count--;
+  assert_valid_list(list);
+}
+
+void grpc_metadata_batch_remove(grpc_exec_ctx *exec_ctx,
+                                grpc_metadata_batch *batch,
+                                grpc_linked_mdelem *storage) {
+  assert_valid_callouts(exec_ctx, batch);
+  maybe_unlink_callout(batch, storage);
+  unlink_storage(&batch->list, storage);
+  GRPC_MDELEM_UNREF(exec_ctx, storage->md);
+  assert_valid_callouts(exec_ctx, batch);
+}
+
+void grpc_metadata_batch_set_value(grpc_exec_ctx *exec_ctx,
+                                   grpc_linked_mdelem *storage,
+                                   grpc_slice value) {
+  grpc_mdelem old_mdelem = storage->md;
+  grpc_mdelem new_mdelem = grpc_mdelem_from_slices(
+      exec_ctx, grpc_slice_ref_internal(GRPC_MDKEY(old_mdelem)), value);
+  storage->md = new_mdelem;
+  GRPC_MDELEM_UNREF(exec_ctx, old_mdelem);
+}
+
+grpc_error *grpc_metadata_batch_substitute(grpc_exec_ctx *exec_ctx,
+                                           grpc_metadata_batch *batch,
+                                           grpc_linked_mdelem *storage,
+                                           grpc_mdelem new_mdelem) {
+  assert_valid_callouts(exec_ctx, batch);
+  grpc_error *error = GRPC_ERROR_NONE;
+  grpc_mdelem old_mdelem = storage->md;
+  if (!grpc_slice_eq(GRPC_MDKEY(new_mdelem), GRPC_MDKEY(old_mdelem))) {
+    maybe_unlink_callout(batch, storage);
+    storage->md = new_mdelem;
+    error = maybe_link_callout(batch, storage);
+    if (error != GRPC_ERROR_NONE) {
+      unlink_storage(&batch->list, storage);
+      GRPC_MDELEM_UNREF(exec_ctx, storage->md);
+    }
+  } else {
+    storage->md = new_mdelem;
+  }
+  GRPC_MDELEM_UNREF(exec_ctx, old_mdelem);
+  assert_valid_callouts(exec_ctx, batch);
+  return error;
+}
+
+void grpc_metadata_batch_clear(grpc_exec_ctx *exec_ctx,
+                               grpc_metadata_batch *batch) {
+  grpc_metadata_batch_destroy(exec_ctx, batch);
+  grpc_metadata_batch_init(batch);
+}
+
+bool grpc_metadata_batch_is_empty(grpc_metadata_batch *batch) {
+  return batch->list.head == NULL && batch->deadline == GRPC_MILLIS_INF_FUTURE;
+}
+
+size_t grpc_metadata_batch_size(grpc_metadata_batch *batch) {
+  size_t size = 0;
+  for (grpc_linked_mdelem *elem = batch->list.head; elem != NULL;
+       elem = elem->next) {
+    size += GRPC_MDELEM_LENGTH(elem->md);
+  }
+  return size;
+}
+
+static void add_error(grpc_error **composite, grpc_error *error,
+                      const char *composite_error_string) {
+  if (error == GRPC_ERROR_NONE) return;
+  if (*composite == GRPC_ERROR_NONE) {
+    *composite = GRPC_ERROR_CREATE_FROM_COPIED_STRING(composite_error_string);
+  }
+  *composite = grpc_error_add_child(*composite, error);
+}
+
+grpc_error *grpc_metadata_batch_filter(grpc_exec_ctx *exec_ctx,
+                                       grpc_metadata_batch *batch,
+                                       grpc_metadata_batch_filter_func func,
+                                       void *user_data,
+                                       const char *composite_error_string) {
+  grpc_linked_mdelem *l = batch->list.head;
+  grpc_error *error = GRPC_ERROR_NONE;
+  while (l) {
+    grpc_linked_mdelem *next = l->next;
+    grpc_filtered_mdelem new_mdelem = func(exec_ctx, user_data, l->md);
+    add_error(&error, new_mdelem.error, composite_error_string);
+    if (GRPC_MDISNULL(new_mdelem.md)) {
+      grpc_metadata_batch_remove(exec_ctx, batch, l);
+    } else if (new_mdelem.md.payload != l->md.payload) {
+      grpc_metadata_batch_substitute(exec_ctx, batch, l, new_mdelem.md);
+    }
+    l = next;
+  }
+  return error;
+}