1.1 --- /dev/null Thu Jan 01 00:00:00 1970 +0000
1.2 +++ b/layout/style/Declaration.h Wed Dec 31 06:09:35 2014 +0100
1.3 @@ -0,0 +1,361 @@
1.4 +/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
1.5 +/* This Source Code Form is subject to the terms of the Mozilla Public
1.6 + * License, v. 2.0. If a copy of the MPL was not distributed with this
1.7 + * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
1.8 +
1.9 +/*
1.10 + * representation of a declaration block (or style attribute) in a CSS
1.11 + * stylesheet
1.12 + */
1.13 +
1.14 +#ifndef mozilla_css_Declaration_h
1.15 +#define mozilla_css_Declaration_h
1.16 +
1.17 +// This header is in EXPORTS because it's used in several places in content/,
1.18 +// but it's not really a public interface.
1.19 +#ifndef MOZILLA_INTERNAL_API
1.20 +#error "This file should only be included within libxul"
1.21 +#endif
1.22 +
1.23 +#include "mozilla/Attributes.h"
1.24 +#include "mozilla/MemoryReporting.h"
1.25 +#include "CSSVariableDeclarations.h"
1.26 +#include "nsCSSDataBlock.h"
1.27 +#include "nsCSSProperty.h"
1.28 +#include "nsCSSProps.h"
1.29 +#include "nsStringFwd.h"
1.30 +#include "nsTArray.h"
1.31 +#include <stdio.h>
1.32 +
1.33 +namespace mozilla {
1.34 +namespace css {
1.35 +
1.36 +// Declaration objects have unusual lifetime rules. Every declaration
1.37 +// begins life in an invalid state which ends when InitializeEmpty or
1.38 +// CompressFrom is called upon it. After that, it can be attached to
1.39 +// exactly one style rule, and will be destroyed when that style rule
1.40 +// is destroyed. A declaration becomes immutable when its style rule's
1.41 +// |RuleMatched| method is called; after that, it must be copied before
1.42 +// it can be modified, which is taken care of by |EnsureMutable|.
1.43 +
1.44 +class Declaration {
1.45 +public:
1.46 + /**
1.47 + * Construct an |Declaration| that is in an invalid state (null
1.48 + * |mData|) and cannot be used until its |CompressFrom| method or
1.49 + * |InitializeEmpty| method is called.
1.50 + */
1.51 + Declaration();
1.52 +
1.53 + Declaration(const Declaration& aCopy);
1.54 +
1.55 + ~Declaration();
1.56 +
1.57 + /**
1.58 + * |ValueAppended| must be called to maintain this declaration's
1.59 + * |mOrder| whenever a property is parsed into an expanded data block
1.60 + * for this declaration. aProperty must not be a shorthand.
1.61 + */
1.62 + void ValueAppended(nsCSSProperty aProperty);
1.63 +
1.64 + void RemoveProperty(nsCSSProperty aProperty);
1.65 +
1.66 + bool HasProperty(nsCSSProperty aProperty) const;
1.67 +
1.68 + void GetValue(nsCSSProperty aProperty, nsAString& aValue) const;
1.69 + void GetAuthoredValue(nsCSSProperty aProperty, nsAString& aValue) const;
1.70 +
1.71 + bool HasImportantData() const {
1.72 + return mImportantData || mImportantVariables;
1.73 + }
1.74 + bool GetValueIsImportant(nsCSSProperty aProperty) const;
1.75 + bool GetValueIsImportant(const nsAString& aProperty) const;
1.76 +
1.77 + /**
1.78 + * Adds a custom property declaration to this object.
1.79 + *
1.80 + * @param aName The variable name (i.e., without the "--" prefix).
1.81 + * @param aType The type of value the variable has.
1.82 + * @param aValue The value of the variable, if aType is
1.83 + * CSSVariableDeclarations::eTokenStream.
1.84 + * @param aIsImportant Whether the declaration is !important.
1.85 + * @param aOverrideImportant When aIsImportant is false, whether an
1.86 + * existing !important declaration will be overridden.
1.87 + */
1.88 + void AddVariableDeclaration(const nsAString& aName,
1.89 + CSSVariableDeclarations::Type aType,
1.90 + const nsString& aValue,
1.91 + bool aIsImportant,
1.92 + bool aOverrideImportant);
1.93 +
1.94 + /**
1.95 + * Removes a custom property declaration from this object.
1.96 + *
1.97 + * @param aName The variable name (i.e., without the "--" prefix).
1.98 + */
1.99 + void RemoveVariableDeclaration(const nsAString& aName);
1.100 +
1.101 + /**
1.102 + * Returns whether a custom property declaration for a variable with
1.103 + * a given name exists on this object.
1.104 + *
1.105 + * @param aName The variable name (i.e., without the "--" prefix).
1.106 + */
1.107 + bool HasVariableDeclaration(const nsAString& aName) const;
1.108 +
1.109 + /**
1.110 + * Gets the string value for a custom property declaration of a variable
1.111 + * with a given name.
1.112 + *
1.113 + * @param aName The variable name (i.e., without the "--" prefix).
1.114 + * @param aValue Out parameter into which the variable's value will be
1.115 + * stored. If the value is 'initial' or 'inherit', that exact string
1.116 + * will be stored in aValue.
1.117 + */
1.118 + void GetVariableDeclaration(const nsAString& aName, nsAString& aValue) const;
1.119 +
1.120 + /**
1.121 + * Returns whether the custom property declaration for a variable with
1.122 + * the given name was !important.
1.123 + */
1.124 + bool GetVariableValueIsImportant(const nsAString& aName) const;
1.125 +
1.126 + uint32_t Count() const {
1.127 + return mOrder.Length();
1.128 + }
1.129 +
1.130 + // Returns whether we actually had a property at aIndex
1.131 + bool GetNthProperty(uint32_t aIndex, nsAString& aReturn) const;
1.132 +
1.133 + void ToString(nsAString& aString) const;
1.134 +
1.135 + nsCSSCompressedDataBlock* GetNormalBlock() const { return mData; }
1.136 + nsCSSCompressedDataBlock* GetImportantBlock() const { return mImportantData; }
1.137 +
1.138 + /**
1.139 + * Initialize this declaration as holding no data. Cannot fail.
1.140 + */
1.141 + void InitializeEmpty();
1.142 +
1.143 + /**
1.144 + * Transfer all of the state from |aExpandedData| into this declaration.
1.145 + * After calling, |aExpandedData| should be in its initial state.
1.146 + * Callers must make sure mOrder is updated as necessary.
1.147 + */
1.148 + void CompressFrom(nsCSSExpandedDataBlock *aExpandedData) {
1.149 + NS_ABORT_IF_FALSE(!mData, "oops");
1.150 + NS_ABORT_IF_FALSE(!mImportantData, "oops");
1.151 + aExpandedData->Compress(getter_Transfers(mData),
1.152 + getter_Transfers(mImportantData));
1.153 + aExpandedData->AssertInitialState();
1.154 + }
1.155 +
1.156 + /**
1.157 + * Transfer all of the state from this declaration into
1.158 + * |aExpandedData| and put this declaration temporarily into an
1.159 + * invalid state (ended by |CompressFrom| or |InitializeEmpty|) that
1.160 + * should last only during parsing. During this time only
1.161 + * |ValueAppended| should be called.
1.162 + */
1.163 + void ExpandTo(nsCSSExpandedDataBlock *aExpandedData) {
1.164 + AssertMutable();
1.165 + aExpandedData->AssertInitialState();
1.166 +
1.167 + NS_ABORT_IF_FALSE(mData, "oops");
1.168 + aExpandedData->Expand(mData.forget(), mImportantData.forget());
1.169 + }
1.170 +
1.171 + /**
1.172 + * Do what |nsIStyleRule::MapRuleInfoInto| needs to do for a style
1.173 + * rule using this declaration for storage.
1.174 + */
1.175 + void MapNormalRuleInfoInto(nsRuleData *aRuleData) const {
1.176 + NS_ABORT_IF_FALSE(mData, "called while expanded");
1.177 + mData->MapRuleInfoInto(aRuleData);
1.178 + if (mVariables) {
1.179 + mVariables->MapRuleInfoInto(aRuleData);
1.180 + }
1.181 + }
1.182 + void MapImportantRuleInfoInto(nsRuleData *aRuleData) const {
1.183 + NS_ABORT_IF_FALSE(mData, "called while expanded");
1.184 + NS_ABORT_IF_FALSE(mImportantData || mImportantVariables,
1.185 + "must have important data or variables");
1.186 + if (mImportantData) {
1.187 + mImportantData->MapRuleInfoInto(aRuleData);
1.188 + }
1.189 + if (mImportantVariables) {
1.190 + mImportantVariables->MapRuleInfoInto(aRuleData);
1.191 + }
1.192 + }
1.193 +
1.194 + /**
1.195 + * Attempt to replace the value for |aProperty| stored in this
1.196 + * declaration with the matching value from |aFromBlock|.
1.197 + * This method may only be called on a mutable declaration.
1.198 + * It will fail (returning false) if |aProperty| is shorthand,
1.199 + * is not already in this declaration, or does not have the indicated
1.200 + * importance level. If it returns true, it erases the value in
1.201 + * |aFromBlock|. |aChanged| is set to true if the declaration
1.202 + * changed as a result of the call, and to false otherwise.
1.203 + */
1.204 + bool TryReplaceValue(nsCSSProperty aProperty, bool aIsImportant,
1.205 + nsCSSExpandedDataBlock& aFromBlock,
1.206 + bool* aChanged)
1.207 + {
1.208 + AssertMutable();
1.209 + NS_ABORT_IF_FALSE(mData, "called while expanded");
1.210 +
1.211 + if (nsCSSProps::IsShorthand(aProperty)) {
1.212 + *aChanged = false;
1.213 + return false;
1.214 + }
1.215 + nsCSSCompressedDataBlock *block = aIsImportant ? mImportantData : mData;
1.216 + // mImportantData might be null
1.217 + if (!block) {
1.218 + *aChanged = false;
1.219 + return false;
1.220 + }
1.221 +
1.222 +#ifdef DEBUG
1.223 + {
1.224 + nsCSSCompressedDataBlock *other = aIsImportant ? mData : mImportantData;
1.225 + NS_ABORT_IF_FALSE(!other || !other->ValueFor(aProperty) ||
1.226 + !block->ValueFor(aProperty),
1.227 + "Property both important and not?");
1.228 + }
1.229 +#endif
1.230 + return block->TryReplaceValue(aProperty, aFromBlock, aChanged);
1.231 + }
1.232 +
1.233 + bool HasNonImportantValueFor(nsCSSProperty aProperty) const {
1.234 + NS_ABORT_IF_FALSE(!nsCSSProps::IsShorthand(aProperty), "must be longhand");
1.235 + return !!mData->ValueFor(aProperty);
1.236 + }
1.237 +
1.238 + /**
1.239 + * Return whether |this| may be modified.
1.240 + */
1.241 + bool IsMutable() const {
1.242 + return !mImmutable;
1.243 + }
1.244 +
1.245 + /**
1.246 + * Copy |this|, if necessary to ensure that it can be modified.
1.247 + */
1.248 + Declaration* EnsureMutable();
1.249 +
1.250 + /**
1.251 + * Crash if |this| cannot be modified.
1.252 + */
1.253 + void AssertMutable() const {
1.254 + NS_ABORT_IF_FALSE(IsMutable(), "someone forgot to call EnsureMutable");
1.255 + }
1.256 +
1.257 + /**
1.258 + * Mark this declaration as unmodifiable. It's 'const' so it can
1.259 + * be called from ToString.
1.260 + */
1.261 + void SetImmutable() const { mImmutable = true; }
1.262 +
1.263 + /**
1.264 + * Clear the data, in preparation for its replacement with entirely
1.265 + * new data by a call to |CompressFrom|.
1.266 + */
1.267 + void ClearData() {
1.268 + AssertMutable();
1.269 + mData = nullptr;
1.270 + mImportantData = nullptr;
1.271 + mVariables = nullptr;
1.272 + mImportantVariables = nullptr;
1.273 + mOrder.Clear();
1.274 + mVariableOrder.Clear();
1.275 + }
1.276 +
1.277 +#ifdef DEBUG
1.278 + void List(FILE* out = stdout, int32_t aIndent = 0) const;
1.279 +#endif
1.280 +
1.281 +private:
1.282 + Declaration& operator=(const Declaration& aCopy) MOZ_DELETE;
1.283 + bool operator==(const Declaration& aCopy) const MOZ_DELETE;
1.284 +
1.285 + void GetValue(nsCSSProperty aProperty, nsAString& aValue,
1.286 + nsCSSValue::Serialization aValueSerialization) const;
1.287 +
1.288 + static void AppendImportanceToString(bool aIsImportant, nsAString& aString);
1.289 + // return whether there was a value in |aValue| (i.e., it had a non-null unit)
1.290 + bool AppendValueToString(nsCSSProperty aProperty, nsAString& aResult) const;
1.291 + bool AppendValueToString(nsCSSProperty aProperty, nsAString& aResult,
1.292 + nsCSSValue::Serialization aValueSerialization) const;
1.293 + // Helper for ToString with strange semantics regarding aValue.
1.294 + void AppendPropertyAndValueToString(nsCSSProperty aProperty,
1.295 + nsAutoString& aValue,
1.296 + nsAString& aResult) const;
1.297 + // helper for ToString that serializes a custom property declaration for
1.298 + // a variable with the specified name
1.299 + void AppendVariableAndValueToString(const nsAString& aName,
1.300 + nsAString& aResult) const;
1.301 +
1.302 +public:
1.303 + /**
1.304 + * Returns the property at the given index in the ordered list of
1.305 + * declarations. For custom properties, eCSSPropertyExtra_variable
1.306 + * is returned.
1.307 + */
1.308 + nsCSSProperty GetPropertyAt(uint32_t aIndex) const {
1.309 + uint32_t value = mOrder[aIndex];
1.310 + if (value >= eCSSProperty_COUNT) {
1.311 + return eCSSPropertyExtra_variable;
1.312 + }
1.313 + return nsCSSProperty(value);
1.314 + }
1.315 +
1.316 + /**
1.317 + * Gets the name of the custom property at the given index in the ordered
1.318 + * list of declarations.
1.319 + */
1.320 + void GetCustomPropertyNameAt(uint32_t aIndex, nsAString& aResult) const {
1.321 + MOZ_ASSERT(mOrder[aIndex] >= eCSSProperty_COUNT);
1.322 + uint32_t variableIndex = mOrder[aIndex] - eCSSProperty_COUNT;
1.323 + aResult.Truncate();
1.324 + aResult.AppendLiteral("--");
1.325 + aResult.Append(mVariableOrder[variableIndex]);
1.326 + }
1.327 +
1.328 + size_t SizeOfIncludingThis(mozilla::MallocSizeOf aMallocSizeOf) const;
1.329 +
1.330 +private:
1.331 + // The order of properties in this declaration. Longhand properties are
1.332 + // represented by their nsCSSProperty value, and each custom property (--*)
1.333 + // is represented by a value that begins at eCSSProperty_COUNT.
1.334 + //
1.335 + // Subtracting eCSSProperty_COUNT from those values that represent custom
1.336 + // properties results in an index into mVariableOrder, which identifies the
1.337 + // specific variable the custom property declaration is for.
1.338 + nsAutoTArray<uint32_t, 8> mOrder;
1.339 +
1.340 + // variable names of custom properties found in mOrder
1.341 + nsTArray<nsString> mVariableOrder;
1.342 +
1.343 + // never null, except while expanded, or before the first call to
1.344 + // InitializeEmpty or CompressFrom.
1.345 + nsAutoPtr<nsCSSCompressedDataBlock> mData;
1.346 +
1.347 + // may be null
1.348 + nsAutoPtr<nsCSSCompressedDataBlock> mImportantData;
1.349 +
1.350 + // may be null
1.351 + nsAutoPtr<CSSVariableDeclarations> mVariables;
1.352 +
1.353 + // may be null
1.354 + nsAutoPtr<CSSVariableDeclarations> mImportantVariables;
1.355 +
1.356 + // set by style rules when |RuleMatched| is called;
1.357 + // also by ToString (hence the 'mutable').
1.358 + mutable bool mImmutable;
1.359 +};
1.360 +
1.361 +} // namespace css
1.362 +} // namespace mozilla
1.363 +
1.364 +#endif /* mozilla_css_Declaration_h */
