22b96ec22a
## Summary * Destroy CSS Cache file when invalid ## Additional Context * Fixes issue where it would attempt to rebuild every book open --- ### AI Usage While CrossPoint doesn't have restrictions on AI tools in contributing, please be transparent about their usage as it helps set the right context for reviewers. Did you use AI tools to help write this code? No
133 lines
4.3 KiB
C++
133 lines
4.3 KiB
C++
#pragma once
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#include <HalStorage.h>
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#include <string>
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#include <unordered_map>
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#include <utility>
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#include <vector>
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#include "CssStyle.h"
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/**
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* Lightweight CSS parser for EPUB stylesheets
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*
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* Parses CSS files and extracts styling information relevant for e-ink display.
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* Uses a two-phase approach: first tokenizes the CSS content, then builds
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* a rule database that can be queried during HTML parsing.
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*
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* Supported selectors:
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* - Element selectors: p, div, h1, etc.
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* - Class selectors: .classname
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* - Combined: element.classname
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* - Grouped: selector1, selector2 { }
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*
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* Not supported (silently ignored):
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* - Descendant/child selectors
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* - Pseudo-classes and pseudo-elements
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* - Media queries (content is skipped)
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* - @import, @font-face, etc.
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*/
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class CssParser {
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public:
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// Bump when CSS cache format or rules change; section caches are invalidated when this changes
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static constexpr uint8_t CSS_CACHE_VERSION = 3;
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explicit CssParser(std::string cachePath) : cachePath(std::move(cachePath)) {}
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~CssParser() = default;
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// Non-copyable
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CssParser(const CssParser&) = delete;
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CssParser& operator=(const CssParser&) = delete;
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/**
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* Load and parse CSS from a file stream.
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* Can be called multiple times to accumulate rules from multiple stylesheets.
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* @param source Open file handle to read from
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* @return true if parsing completed (even if no rules found)
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*/
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bool loadFromStream(FsFile& source);
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/**
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* Look up the style for an HTML element, considering tag name and class attributes.
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* Applies CSS cascade: element style < class style < element.class style
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*
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* @param tagName The HTML element name (e.g., "p", "div")
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* @param classAttr The class attribute value (may contain multiple space-separated classes)
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* @return Combined style with all applicable rules merged
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*/
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[[nodiscard]] CssStyle resolveStyle(const std::string& tagName, const std::string& classAttr) const;
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/**
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* Parse an inline style attribute string.
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* @param styleValue The value of a style="" attribute
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* @return Parsed style properties
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*/
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[[nodiscard]] static CssStyle parseInlineStyle(const std::string& styleValue);
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/**
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* Check if any rules have been loaded
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*/
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[[nodiscard]] bool empty() const { return rulesBySelector_.empty(); }
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/**
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* Get count of loaded rule sets
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*/
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[[nodiscard]] size_t ruleCount() const { return rulesBySelector_.size(); }
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/**
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* Clear all loaded rules
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*/
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void clear() { rulesBySelector_.clear(); }
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/**
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* Check if CSS rules cache file exists
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*/
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bool hasCache() const;
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/**
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* Delete CSS rules cache file exists
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*/
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void deleteCache() const;
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/**
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* Save parsed CSS rules to a cache file.
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* @return true if cache was written successfully
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*/
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bool saveToCache() const;
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/**
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* Load CSS rules from a cache file.
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* Clears any existing rules before loading.
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* @return true if cache was loaded successfully
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*/
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bool loadFromCache();
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private:
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// Storage: maps normalized selector -> style properties
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std::unordered_map<std::string, CssStyle> rulesBySelector_;
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std::string cachePath;
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// Internal parsing helpers
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void processRuleBlockWithStyle(const std::string& selectorGroup, const CssStyle& style);
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static CssStyle parseDeclarations(const std::string& declBlock);
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static void parseDeclarationIntoStyle(const std::string& decl, CssStyle& style, std::string& propNameBuf,
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std::string& propValueBuf);
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// Individual property value parsers
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static CssTextAlign interpretAlignment(const std::string& val);
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static CssFontStyle interpretFontStyle(const std::string& val);
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static CssFontWeight interpretFontWeight(const std::string& val);
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static CssTextDecoration interpretDecoration(const std::string& val);
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static CssLength interpretLength(const std::string& val);
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/** Returns true only when a numeric length was parsed (e.g. 2em, 50%). False for auto/inherit/initial. */
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static bool tryInterpretLength(const std::string& val, CssLength& out);
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// String utilities
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static std::string normalized(const std::string& s);
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static void normalizedInto(const std::string& s, std::string& out);
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static std::vector<std::string> splitOnChar(const std::string& s, char delimiter);
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static std::vector<std::string> splitWhitespace(const std::string& s);
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};
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