diff options
Diffstat (limited to 'dom/base/XPathGenerator.cpp')
| -rw-r--r-- | dom/base/XPathGenerator.cpp | 192 |
1 files changed, 192 insertions, 0 deletions
diff --git a/dom/base/XPathGenerator.cpp b/dom/base/XPathGenerator.cpp new file mode 100644 index 0000000000..ca0305fe80 --- /dev/null +++ b/dom/base/XPathGenerator.cpp @@ -0,0 +1,192 @@ +/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */ +/* vim: set ts=8 sts=2 et sw=2 tw=80: */ +/* This Source Code Form is subject to the terms of the Mozilla Public + * License, v. 2.0. If a copy of the MPL was not distributed with this file, + * You can obtain one at http://mozilla.org/MPL/2.0/. */ + +#include "XPathGenerator.h" + +#include "nsGkAtoms.h" +#include "Element.h" +#include "nsTArray.h" + +/** + * Check whether a character is a non-word character. A non-word character is a + * character that isn't in ('a'..'z') or in ('A'..'Z') or a number or an + * underscore. + * */ +bool IsNonWordCharacter(const char16_t& aChar) { + if (((char16_t('A') <= aChar) && (aChar <= char16_t('Z'))) || + ((char16_t('a') <= aChar) && (aChar <= char16_t('z'))) || + ((char16_t('0') <= aChar) && (aChar <= char16_t('9'))) || + (aChar == char16_t('_'))) { + return false; + } else { + return true; + } +} + +/** + * Check whether a string contains a non-word character. + * */ +bool ContainNonWordCharacter(const nsAString& aStr) { + const char16_t* cur = aStr.BeginReading(); + const char16_t* end = aStr.EndReading(); + for (; cur < end; ++cur) { + if (IsNonWordCharacter(*cur)) { + return true; + } + } + return false; +} + +/** + * Get the prefix according to the given namespace and assign the result to + * aResult. + * */ +void GetPrefix(const nsINode* aNode, nsAString& aResult) { + if (aNode->IsXULElement()) { + aResult.AssignLiteral(u"xul"); + } else if (aNode->IsHTMLElement()) { + aResult.AssignLiteral(u"xhtml"); + } +} + +void GetNameAttribute(const nsINode* aNode, nsAString& aResult) { + if (aNode->HasName()) { + const mozilla::dom::Element* elem = aNode->AsElement(); + elem->GetAttr(kNameSpaceID_None, nsGkAtoms::name, aResult); + } +} + +/** + * Put all sequences of ' in a string in between '," and ",' . And then put + * the result string in between concat(' and '). + * + * For example, a string 'a'' will return result concat('',"'",'a',"''",'') + * */ +void GenerateConcatExpression(const nsAString& aStr, nsAString& aResult) { + const char16_t* cur = aStr.BeginReading(); + const char16_t* end = aStr.EndReading(); + + // Put all sequences of ' in between '," and ",' + nsAutoString result; + const char16_t* nonQuoteBeginPtr = nullptr; + const char16_t* quoteBeginPtr = nullptr; + for (; cur < end; ++cur) { + if (char16_t('\'') == *cur) { + if (nonQuoteBeginPtr) { + result.Append(nonQuoteBeginPtr, cur - nonQuoteBeginPtr); + nonQuoteBeginPtr = nullptr; + } + if (!quoteBeginPtr) { + result.AppendLiteral(u"\',\""); + quoteBeginPtr = cur; + } + } else { + if (!nonQuoteBeginPtr) { + nonQuoteBeginPtr = cur; + } + if (quoteBeginPtr) { + result.Append(quoteBeginPtr, cur - quoteBeginPtr); + result.AppendLiteral(u"\",\'"); + quoteBeginPtr = nullptr; + } + } + } + + if (quoteBeginPtr) { + result.Append(quoteBeginPtr, cur - quoteBeginPtr); + result.AppendLiteral(u"\",\'"); + } else if (nonQuoteBeginPtr) { + result.Append(nonQuoteBeginPtr, cur - nonQuoteBeginPtr); + } + + // Prepend concat(' and append '). + aResult.Assign(u"concat(\'"_ns + result + u"\')"_ns); +} + +void XPathGenerator::QuoteArgument(const nsAString& aArg, nsAString& aResult) { + if (!aArg.Contains('\'')) { + aResult.Assign(u"\'"_ns + aArg + u"\'"_ns); + } else if (!aArg.Contains('\"')) { + aResult.Assign(u"\""_ns + aArg + u"\""_ns); + } else { + GenerateConcatExpression(aArg, aResult); + } +} + +void XPathGenerator::EscapeName(const nsAString& aName, nsAString& aResult) { + if (ContainNonWordCharacter(aName)) { + nsAutoString quotedArg; + QuoteArgument(aName, quotedArg); + aResult.Assign(u"*[local-name()="_ns + quotedArg + u"]"_ns); + } else { + aResult.Assign(aName); + } +} + +void XPathGenerator::Generate(const nsINode* aNode, nsAString& aResult) { + if (!aNode->GetParentNode()) { + aResult.Truncate(); + return; + } + + nsAutoString nodeNamespaceURI; + aNode->GetNamespaceURI(nodeNamespaceURI); + const nsString& nodeLocalName = aNode->LocalName(); + + nsAutoString prefix; + nsAutoString tag; + nsAutoString nodeEscapeName; + GetPrefix(aNode, prefix); + EscapeName(nodeLocalName, nodeEscapeName); + if (prefix.IsEmpty()) { + tag.Assign(nodeEscapeName); + } else { + tag.Assign(prefix + u":"_ns + nodeEscapeName); + } + + if (aNode->HasID()) { + // this must be an element + const mozilla::dom::Element* elem = aNode->AsElement(); + nsAutoString elemId; + nsAutoString quotedArgument; + elem->GetId(elemId); + QuoteArgument(elemId, quotedArgument); + aResult.Assign(u"//"_ns + tag + u"[@id="_ns + quotedArgument + u"]"_ns); + return; + } + + int32_t count = 1; + nsAutoString nodeNameAttribute; + GetNameAttribute(aNode, nodeNameAttribute); + for (const mozilla::dom::Element* e = aNode->GetPreviousElementSibling(); e; + e = e->GetPreviousElementSibling()) { + nsAutoString elementNamespaceURI; + e->GetNamespaceURI(elementNamespaceURI); + nsAutoString elementNameAttribute; + GetNameAttribute(e, elementNameAttribute); + if (e->LocalName().Equals(nodeLocalName) && + elementNamespaceURI.Equals(nodeNamespaceURI) && + (nodeNameAttribute.IsEmpty() || + elementNameAttribute.Equals(nodeNameAttribute))) { + ++count; + } + } + + nsAutoString namePart; + nsAutoString countPart; + if (!nodeNameAttribute.IsEmpty()) { + nsAutoString quotedArgument; + QuoteArgument(nodeNameAttribute, quotedArgument); + namePart.Assign(u"[@name="_ns + quotedArgument + u"]"_ns); + } + if (count != 1) { + countPart.AssignLiteral(u"["); + countPart.AppendInt(count); + countPart.AppendLiteral(u"]"); + } + Generate(aNode->GetParentNode(), aResult); + aResult.Append(u"/"_ns + tag + namePart + countPart); +} |