Rename Palette to FRAME (#4182)

* palette -> frame

* PALETTE, Palette -> FRAME

* Move folder pallete -> frame

* Update docs/Structure.adoc

Co-Authored-By: Benjamin Kampmann <ben.kampmann@googlemail.com>

* Update docs/README.adoc

Co-Authored-By: Benjamin Kampmann <ben.kampmann@googlemail.com>

* Update README.adoc

substrate/frame/support/src/storage/child.rs

@@ -0,0 +1,119 @@
+// Copyright 2019 Parity Technologies (UK) Ltd.
+// This file is part of Substrate.
+
+// Substrate is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+
+// Substrate is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// You should have received a copy of the GNU General Public License
+// along with Substrate.  If not, see <http://www.gnu.org/licenses/>.
+
+//! Operation on runtime child storages.
+//!
+//! This module is a currently only a variant of unhashed with additional `storage_key`.
+//! Note that `storage_key` must be unique and strong (strong in the sense of being long enough to
+//! avoid collision from a resistant hash function (which unique implies)).
+// NOTE: could replace unhashed by having only one kind of storage (root being null storage key (storage_key can become Option<&[u8]>).
+
+use crate::rstd::prelude::*;
+use codec::{Codec, Encode, Decode};
+
+/// Return the value of the item in storage under `key`, or `None` if there is no explicit entry.
+pub fn get<T: Decode + Sized>(storage_key: &[u8], key: &[u8]) -> Option<T> {
+	runtime_io::storage::child_get(storage_key, key).and_then(|v| {
+		Decode::decode(&mut &v[..]).map(Some).unwrap_or_else(|_| {
+			// TODO #3700: error should be handleable.
+			runtime_print!("ERROR: Corrupted state in child trie at {:?}/{:?}", storage_key, key);
+			None
+		})
+	})
+}
+
+/// Return the value of the item in storage under `key`, or the type's default if there is no
+/// explicit entry.
+pub fn get_or_default<T: Decode + Sized + Default>(storage_key: &[u8], key: &[u8]) -> T {
+	get(storage_key, key).unwrap_or_else(Default::default)
+}
+
+/// Return the value of the item in storage under `key`, or `default_value` if there is no
+/// explicit entry.
+pub fn get_or<T: Decode + Sized>(storage_key: &[u8], key: &[u8], default_value: T) -> T {
+	get(storage_key, key).unwrap_or(default_value)
+}
+
+/// Return the value of the item in storage under `key`, or `default_value()` if there is no
+/// explicit entry.
+pub fn get_or_else<T: Decode + Sized, F: FnOnce() -> T>(
+	storage_key: &[u8],
+	key: &[u8],
+	default_value: F,
+) -> T {
+	get(storage_key, key).unwrap_or_else(default_value)
+}
+
+/// Put `value` in storage under `key`.
+pub fn put<T: Encode>(storage_key: &[u8], key: &[u8], value: &T) {
+	value.using_encoded(|slice| runtime_io::storage::child_set(storage_key, key, slice));
+}
+
+/// Remove `key` from storage, returning its value if it had an explicit entry or `None` otherwise.
+pub fn take<T: Decode + Sized>(storage_key: &[u8], key: &[u8]) -> Option<T> {
+	let r = get(storage_key, key);
+	if r.is_some() {
+		kill(storage_key, key);
+	}
+	r
+}
+
+/// Remove `key` from storage, returning its value, or, if there was no explicit entry in storage,
+/// the default for its type.
+pub fn take_or_default<T: Codec + Sized + Default>(storage_key: &[u8], key: &[u8]) -> T {
+	take(storage_key, key).unwrap_or_else(Default::default)
+}
+
+/// Return the value of the item in storage under `key`, or `default_value` if there is no
+/// explicit entry. Ensure there is no explicit entry on return.
+pub fn take_or<T: Codec + Sized>(storage_key: &[u8],key: &[u8], default_value: T) -> T {
+	take(storage_key, key).unwrap_or(default_value)
+}
+
+/// Return the value of the item in storage under `key`, or `default_value()` if there is no
+/// explicit entry. Ensure there is no explicit entry on return.
+pub fn take_or_else<T: Codec + Sized, F: FnOnce() -> T>(
+	storage_key: &[u8],
+	key: &[u8],
+	default_value: F,
+) -> T {
+	take(storage_key, key).unwrap_or_else(default_value)
+}
+
+/// Check to see if `key` has an explicit entry in storage.
+pub fn exists(storage_key: &[u8], key: &[u8]) -> bool {
+	runtime_io::storage::child_read(storage_key, key, &mut [0;0][..], 0).is_some()
+}
+
+/// Remove all `storage_key` key/values
+pub fn kill_storage(storage_key: &[u8]) {
+	runtime_io::storage::child_storage_kill(storage_key)
+}
+
+/// Ensure `key` has no explicit entry in storage.
+pub fn kill(storage_key: &[u8], key: &[u8]) {
+	runtime_io::storage::child_clear(storage_key, key);
+}
+
+/// Get a Vec of bytes from storage.
+pub fn get_raw(storage_key: &[u8], key: &[u8]) -> Option<Vec<u8>> {
+	runtime_io::storage::child_get(storage_key, key)
+}
+
+/// Put a raw byte slice into storage.
+pub fn put_raw(storage_key: &[u8], key: &[u8], value: &[u8]) {
+	runtime_io::storage::child_set(storage_key, key, value)
+}