chromium/third_party/blink/public/common/permissions_policy/document_policy.h

// Copyright 2019 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#ifndef THIRD_PARTY_BLINK_PUBLIC_COMMON_PERMISSIONS_POLICY_DOCUMENT_POLICY_H_
#define THIRD_PARTY_BLINK_PUBLIC_COMMON_PERMISSIONS_POLICY_DOCUMENT_POLICY_H_

#include <memory>

#include "base/containers/flat_map.h"
#include "third_party/blink/public/common/common_export.h"
#include "third_party/blink/public/common/permissions_policy/document_policy_features.h"
#include "third_party/blink/public/common/permissions_policy/policy_value.h"
#include "third_party/blink/public/mojom/permissions_policy/document_policy_feature.mojom.h"
#include "third_party/blink/public/mojom/permissions_policy/policy_value.mojom.h"

namespace blink {

// Document Policy is a mechanism for controlling the behaviour of web platform
// features in a document, and for requesting such changes in embedded frames.
// (The specific changes which are made depend on the feature; see the
// specification for details).
//
// Policies can be defined in the HTTP header stream, with the |Document-Policy|
// HTTP header, or can be set by the |policy| attributes on the iframe element
// which embeds the document.
//
// See
// https://github.com/w3c/webappsec-permissions-policy/blob/master/document-policy-explainer.md
//
// Key concepts:
//
// Features
// --------
// Features which can be controlled by policy are defined by instances of enum
// mojom::DocumentPolicyFeature, declared in |document_policy_feature.mojom|.
//
// Declarations
// ------------
// A document policy declaration is a mapping of a feature name to a policy
// value. A set of such declarations is a declared policy. The declared policy
// is attached to a document.
//
// Required Policy
// ----------------
// In addition to the declared policy (which may be empty), every frame has
// an required policy, which is set by the embedding document (or inherited
// from its parent). Any document loaded into a frame with a required policy
// must have a declared policy which is compatible with it. Frames may add new
// requirements to their own subframes, but cannot relax any existing ones.
//
// Advertised Policy
// -----------------
// If a frame has a non-empty required policy, the requirements will be
// advertised on the outgoing HTTP request for any document to be loaded in that
// frame, in the Sec-Required-Document-Policy HTTP header.
//
// Defaults
// --------
// Each defined feature has a default policy, which determines the threshold
// value to use when no policy has been declared.

class BLINK_COMMON_EXPORT DocumentPolicy { … };

bool inline operator==(const DocumentPolicy::ParsedDocumentPolicy& lhs,
                       const DocumentPolicy::ParsedDocumentPolicy& rhs) { … }

}  // namespace blink

#endif  // THIRD_PARTY_BLINK_PUBLIC_COMMON_PERMISSIONS_POLICY_DOCUMENT_POLICY_H_