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/* -*- 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);
}
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