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db975b21a8
Here are some benefits to define those constants in constexpr variables: 1. Better assertion messages. For example, without this patch, the assertion in bug 1870103 looks like: ``` Assertion failure: cbSize.BSize(wm) == nscoord((1 << 30) - 1) ``` With this patch, it looks like: ``` Assertion failure: cbSize.BSize(wm) == NS_UNCONSTRAINEDSIZE ``` 2. We can use those constants in a debugger. This patch doesn't change behavior. Differential Revision: https://phabricator.services.mozilla.com/D196708
108 lines
3.8 KiB
C++
108 lines
3.8 KiB
C++
/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
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/* vim: set ts=8 sts=2 et sw=2 tw=80: */
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/* This Source Code Form is subject to the terms of the Mozilla Public
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* License, v. 2.0. If a copy of the MPL was not distributed with this
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* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
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/* constants used throughout the Layout module */
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#ifndef LayoutConstants_h___
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#define LayoutConstants_h___
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#include "mozilla/EnumSet.h"
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#include "Units.h"
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/**
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* Constant used to indicate an unconstrained size.
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*
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* NOTE: The constants defined in this file are semantically used as symbolic
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* values, so user should not depend on the underlying numeric values. If
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* new specific use cases arise, define a new constant here.
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*/
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inline constexpr nscoord NS_UNCONSTRAINEDSIZE = nscoord_MAX;
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// NS_AUTOOFFSET is assumed to have the same value as NS_UNCONSTRAINEDSIZE.
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inline constexpr nscoord NS_AUTOOFFSET = NS_UNCONSTRAINEDSIZE;
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// +1 is to avoid clamped huge margin values being processed as auto margins
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inline constexpr nscoord NS_AUTOMARGIN = NS_UNCONSTRAINEDSIZE + 1;
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inline constexpr nscoord NS_INTRINSIC_ISIZE_UNKNOWN = nscoord_MIN;
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namespace mozilla {
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/**
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* Bit-flags to pass to various functions that compute sizes like
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* nsIFrame::ComputeSize().
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*/
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enum class ComputeSizeFlag : uint8_t {
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/**
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* Set if the frame is in a context where non-replaced blocks should
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* shrink-wrap (e.g., it's floating, absolutely positioned, or
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* inline-block).
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*/
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ShrinkWrap,
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/**
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* Set if this is a grid measuring reflow, to prevent stretching.
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*/
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IsGridMeasuringReflow,
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/**
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* Indicates that we should clamp the margin-box min-size to the given CB
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* size. This is used for implementing the grid area clamping here:
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* https://drafts.csswg.org/css-grid/#min-size-auto
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*/
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IClampMarginBoxMinSize, // clamp in our inline axis
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BClampMarginBoxMinSize, // clamp in our block axis
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/**
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* The frame is stretching (per CSS Box Alignment) and doesn't have an
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* Automatic Minimum Size in the indicated axis.
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* (may be used for both flex/grid items, but currently only used for Grid)
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* https://drafts.csswg.org/css-grid/#min-size-auto
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* https://drafts.csswg.org/css-align-3/#valdef-justify-self-stretch
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*/
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IApplyAutoMinSize, // Only has an effect when the ShrinkWrap bit is unset.
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};
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using ComputeSizeFlags = mozilla::EnumSet<ComputeSizeFlag>;
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/**
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* The fallback size of width is 300px and the aspect-ratio is 2:1, based on
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* CSS2 section 10.3.2 and CSS Sizing Level 3 section 5.1:
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* https://drafts.csswg.org/css2/visudet.html#inline-replaced-width
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* https://drafts.csswg.org/css-sizing-3/#intrinsic-sizes
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*/
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inline constexpr CSSIntCoord kFallbackIntrinsicWidthInPixels(300);
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inline constexpr CSSIntCoord kFallbackIntrinsicHeightInPixels(150);
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inline constexpr CSSIntSize kFallbackIntrinsicSizeInPixels(
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kFallbackIntrinsicWidthInPixels, kFallbackIntrinsicHeightInPixels);
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inline constexpr nscoord kFallbackIntrinsicWidth =
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kFallbackIntrinsicWidthInPixels * AppUnitsPerCSSPixel();
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inline constexpr nscoord kFallbackIntrinsicHeight =
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kFallbackIntrinsicHeightInPixels * AppUnitsPerCSSPixel();
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inline constexpr nsSize kFallbackIntrinsicSize(kFallbackIntrinsicWidth,
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kFallbackIntrinsicHeight);
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/**
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* This is used in some nsLayoutUtils functions.
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* Declared here so that fewer files need to include nsLayoutUtils.h.
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*/
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enum class IntrinsicISizeType { MinISize, PrefISize };
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enum class ContentRelevancyReason {
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// If the content of this Frame is on screen or nearly on screen.
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Visible,
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// If this Frame's element has focus in its subtree.
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FocusInSubtree,
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// If this Frame's content is part of a selection.
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Selected,
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};
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using ContentRelevancy = EnumSet<ContentRelevancyReason, uint8_t>;
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} // namespace mozilla
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#endif // LayoutConstants_h___
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