gecko-dev/dom/xslt/xpath/XPathExpression.cpp

/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* 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 "XPathExpression.h"

#include <utility>

#include "XPathResult.h"
#include "mozilla/dom/BindingUtils.h"
#include "mozilla/dom/Text.h"
#include "mozilla/dom/XPathResultBinding.h"
#include "nsError.h"
#include "nsINode.h"
#include "txExpr.h"
#include "txExprResult.h"
#include "txIXPathContext.h"
#include "txURIUtils.h"
#include "txXPathTreeWalker.h"

namespace mozilla::dom {

class EvalContextImpl : public txIEvalContext {
 public:
  EvalContextImpl(const txXPathNode& aContextNode, uint32_t aContextPosition,
                  uint32_t aContextSize, txResultRecycler* aRecycler)
      : mContextNode(aContextNode),
        mContextPosition(aContextPosition),
        mContextSize(aContextSize),
        mLastError(NS_OK),
        mRecycler(aRecycler) {}

  nsresult getError() { return mLastError; }

  TX_DECL_EVAL_CONTEXT;

 private:
  const txXPathNode& mContextNode;
  uint32_t mContextPosition;
  uint32_t mContextSize;
  nsresult mLastError;
  RefPtr<txResultRecycler> mRecycler;
};

XPathExpression::XPathExpression(UniquePtr<Expr>&& aExpression,
                                 txResultRecycler* aRecycler,
                                 Document* aDocument)
    : mExpression(std::move(aExpression)),
      mRecycler(aRecycler),
      mDocument(do_GetWeakReference(aDocument)),
      mCheckDocument(aDocument != nullptr) {}

XPathExpression::~XPathExpression() = default;

already_AddRefed<XPathResult> XPathExpression::EvaluateWithContext(
    JSContext* aCx, nsINode& aContextNode, uint32_t aContextPosition,
    uint32_t aContextSize, uint16_t aType, JS::Handle<JSObject*> aInResult,
    ErrorResult& aRv) {
  RefPtr<XPathResult> inResult;
  if (aInResult) {
    nsresult rv = UNWRAP_OBJECT(XPathResult, aInResult, inResult);
    if (NS_FAILED(rv) && rv != NS_ERROR_XPC_BAD_CONVERT_JS) {
      aRv.Throw(rv);
      return nullptr;
    }
  }

  return EvaluateWithContext(aContextNode, aContextPosition, aContextSize,
                             aType, inResult, aRv);
}

already_AddRefed<XPathResult> XPathExpression::EvaluateWithContext(
    nsINode& aContextNode, uint32_t aContextPosition, uint32_t aContextSize,
    uint16_t aType, XPathResult* aInResult, ErrorResult& aRv) {
  if (aContextPosition > aContextSize) {
    aRv.Throw(NS_ERROR_FAILURE);
    return nullptr;
  }

  if (aType > XPathResult_Binding::FIRST_ORDERED_NODE_TYPE) {
    aRv.Throw(NS_ERROR_DOM_NOT_SUPPORTED_ERR);
    return nullptr;
  }

  if (!nsContentUtils::LegacyIsCallerNativeCode() &&
      !nsContentUtils::CanCallerAccess(&aContextNode)) {
    aRv.Throw(NS_ERROR_DOM_SECURITY_ERR);
    return nullptr;
  }

  if (mCheckDocument) {
    nsCOMPtr<Document> doc = do_QueryReferent(mDocument);
    if (doc != aContextNode.OwnerDoc()) {
      aRv.Throw(NS_ERROR_DOM_WRONG_DOCUMENT_ERR);
      return nullptr;
    }
  }

  uint16_t nodeType = aContextNode.NodeType();

  if (nodeType == nsINode::TEXT_NODE ||
      nodeType == nsINode::CDATA_SECTION_NODE) {
    Text* textNode = aContextNode.GetAsText();
    MOZ_ASSERT(textNode);

    uint32_t textLength = textNode->Length();
    if (textLength == 0) {
      aRv.Throw(NS_ERROR_DOM_NOT_SUPPORTED_ERR);
      return nullptr;
    }

    // XXX Need to get logical XPath text node for CDATASection
    //     and Text nodes.
  } else if (nodeType != nsINode::DOCUMENT_NODE &&
             nodeType != nsINode::ELEMENT_NODE &&
             nodeType != nsINode::ATTRIBUTE_NODE &&
             nodeType != nsINode::COMMENT_NODE &&
             nodeType != nsINode::PROCESSING_INSTRUCTION_NODE) {
    aRv.Throw(NS_ERROR_DOM_NOT_SUPPORTED_ERR);
    return nullptr;
  }

  UniquePtr<txXPathNode> contextNode(
      txXPathNativeNode::createXPathNode(&aContextNode));
  if (!contextNode) {
    aRv.Throw(NS_ERROR_FAILURE);
    return nullptr;
  }

  EvalContextImpl eContext(*contextNode, aContextPosition, aContextSize,
                           mRecycler);
  RefPtr<txAExprResult> exprResult;
  aRv = mExpression->evaluate(&eContext, getter_AddRefs(exprResult));
  if (aRv.Failed()) {
    return nullptr;
  }

  uint16_t resultType = aType;
  if (aType == XPathResult::ANY_TYPE) {
    short exprResultType = exprResult->getResultType();
    switch (exprResultType) {
      case txAExprResult::NUMBER:
        resultType = XPathResult::NUMBER_TYPE;
        break;
      case txAExprResult::STRING:
        resultType = XPathResult::STRING_TYPE;
        break;
      case txAExprResult::BOOLEAN:
        resultType = XPathResult::BOOLEAN_TYPE;
        break;
      case txAExprResult::NODESET:
        resultType = XPathResult::UNORDERED_NODE_ITERATOR_TYPE;
        break;
      case txAExprResult::RESULT_TREE_FRAGMENT:
        aRv.Throw(NS_ERROR_FAILURE);
        return nullptr;
    }
  }

  RefPtr<XPathResult> xpathResult = aInResult;
  if (!xpathResult) {
    xpathResult = new XPathResult(&aContextNode);
  }

  xpathResult->SetExprResult(exprResult, resultType, &aContextNode, aRv);
  if (aRv.Failed()) {
    return nullptr;
  }

  return xpathResult.forget();
}

/*
 * Implementation of the txIEvalContext private to XPathExpression
 * EvalContextImpl bases on only one context node and no variables
 */

nsresult EvalContextImpl::getVariable(int32_t aNamespace, nsAtom* aLName,
                                      txAExprResult*& aResult) {
  aResult = 0;
  return NS_ERROR_INVALID_ARG;
}

nsresult EvalContextImpl::isStripSpaceAllowed(const txXPathNode& aNode,
                                              bool& aAllowed) {
  aAllowed = false;

  return NS_OK;
}

void* EvalContextImpl::getPrivateContext() {
  // we don't have a private context here.
  return nullptr;
}

txResultRecycler* EvalContextImpl::recycler() { return mRecycler; }

void EvalContextImpl::receiveError(const nsAString& aMsg, nsresult aRes) {
  mLastError = aRes;
  // forward aMsg to console service?
}

const txXPathNode& EvalContextImpl::getContextNode() { return mContextNode; }

uint32_t EvalContextImpl::size() { return mContextSize; }

uint32_t EvalContextImpl::position() { return mContextPosition; }

}  // namespace mozilla::dom