Source/platform/URLPatternMatcher.cpp

/*
 * Copyright (C) 2009, 2010 Apple Inc. All rights reserved.
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 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
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 *    documentation and/or other materials provided with the distribution.
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 * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL APPLE COMPUTER, INC. OR
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#include "config.h"
#include "platform/URLPatternMatcher.h"

#include "platform/weborigin/KURL.h"
#include "wtf/StdLibExtras.h"

namespace WebCore {

bool URLPatternMatcher::matchesPatterns(const KURL& url, const Vector<String>& whitelist)
{
    // If there is no whitelist at all, then all URLs are assumed to be in the whitelist.
    if (whitelist.isEmpty())
        return true;

    for (size_t i = 0; i < whitelist.size(); ++i) {
        URLPatternMatcher contentPattern(whitelist[i]);
        if (contentPattern.matches(url))
            return true;
    }

    return false;
}

bool URLPatternMatcher::parse(const String& pattern)
{
    DEFINE_STATIC_LOCAL(const String, schemeSeparator, ("://"));

    size_t schemeEndPos = pattern.find(schemeSeparator);
    if (schemeEndPos == kNotFound)
        return false;

    m_scheme = pattern.left(schemeEndPos);

    unsigned hostStartPos = schemeEndPos + schemeSeparator.length();
    if (hostStartPos >= pattern.length())
        return false;

    int pathStartPos = 0;

    if (equalIgnoringCase(m_scheme, "file")) {
        pathStartPos = hostStartPos;
    } else {
        size_t hostEndPos = pattern.find("/", hostStartPos);
        if (hostEndPos == kNotFound)
            return false;

        m_host = pattern.substring(hostStartPos, hostEndPos - hostStartPos);
        m_matchSubdomains = false;

        if (m_host == "*") {
            // The pattern can be just '*', which means match all domains.
            m_host = "";
            m_matchSubdomains = true;
        } else if (m_host.startsWith("*.")) {
            // The first component can be '*', which means to match all subdomains.
            m_host = m_host.substring(2); // Length of "*."
            m_matchSubdomains = true;
        }

        // No other '*' can occur in the host.
        if (m_host.find("*") != kNotFound)
            return false;

        pathStartPos = hostEndPos;
    }

    m_path = pattern.right(pattern.length() - pathStartPos);

    return true;
}

bool URLPatternMatcher::matches(const KURL& test) const
{
    if (m_invalid)
        return false;

    if (!equalIgnoringCase(test.protocol(), m_scheme))
        return false;

    if (!equalIgnoringCase(m_scheme, "file") && !matchesHost(test))
        return false;

    return matchesPath(test);
}

bool URLPatternMatcher::matchesHost(const KURL& test) const
{
    const String& host = test.host();
    if (equalIgnoringCase(host, m_host))
        return true;

    if (!m_matchSubdomains)
        return false;

    // If we're matching subdomains, and we have no host, that means the pattern
    // was <scheme>://*/<whatever>, so we match anything.
    if (!m_host.length())
        return true;

    // Check if the domain is a subdomain of our host.
    if (!host.endsWith(m_host, false))
        return false;

    ASSERT(host.length() > m_host.length());

    // Check that the character before the suffix is a period.
    return host[host.length() - m_host.length() - 1] == '.';
}

struct MatchTester {
    const String m_pattern;
    unsigned m_patternIndex;

    const String m_test;
    unsigned m_testIndex;

    MatchTester(const String& pattern, const String& test)
    : m_pattern(pattern)
    , m_patternIndex(0)
    , m_test(test)
    , m_testIndex(0)
    {
    }

    bool testStringFinished() const { return m_testIndex >= m_test.length(); }
    bool patternStringFinished() const { return m_patternIndex >= m_pattern.length(); }

    void eatWildcard()
    {
        while (!patternStringFinished()) {
            if (m_pattern[m_patternIndex] != '*')
                return;
            m_patternIndex++;
        }
    }

    void eatSameChars()
    {
        while (!patternStringFinished() && !testStringFinished()) {
            if (m_pattern[m_patternIndex] == '*')
                return;
            if (m_pattern[m_patternIndex] != m_test[m_testIndex])
                return;
            m_patternIndex++;
            m_testIndex++;
        }
    }

    bool test()
    {
        // Eat all the matching chars.
        eatSameChars();

        // If the string is finished, then the pattern must be empty too, or contains
        // only wildcards.
        if (testStringFinished()) {
            eatWildcard();
            if (patternStringFinished())
                return true;
            return false;
        }

        // Pattern is empty but not string, this is not a match.
        if (patternStringFinished())
            return false;

        // If we don't encounter a *, then we're hosed.
        if (m_pattern[m_patternIndex] != '*')
            return false;

        while (!testStringFinished()) {
            MatchTester nextMatch(*this);
            nextMatch.m_patternIndex++;
            if (nextMatch.test())
                return true;
            m_testIndex++;
        }

        // We reached the end of the string. Let's see if the pattern contains only wildcards.
        eatWildcard();
        return patternStringFinished();
    }
};

bool URLPatternMatcher::matchesPath(const KURL& test) const
{
    MatchTester match(m_path, test.path());
    return match.test();
}

} // namespace WebCore