xslt/xslt/txKeyFunctionCall.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 <utility>

#include "mozilla/HashFunctions.h"
#include "nsGkAtoms.h"
#include "nsReadableUtils.h"
#include "txExecutionState.h"
#include "txKey.h"
#include "txNamespaceMap.h"
#include "txSingleNodeContext.h"
#include "txXSLTFunctions.h"
#include "txXSLTPatterns.h"

using namespace mozilla;

/*
 * txKeyFunctionCall
 * A representation of the XSLT additional function: key()
 */

/*
 * Creates a new key function call
 */
txKeyFunctionCall::txKeyFunctionCall(txNamespaceMap* aMappings)
    : mMappings(aMappings) {}

/*
 * Evaluates a key() xslt-function call. First argument is name of key
 * to use, second argument is value to look up.
 * @param aContext the context node for evaluation of this Expr
 * @param aCs      the ContextState containing the stack information needed
 *                 for evaluation
 * @return the result of the evaluation
 */
nsresult txKeyFunctionCall::evaluate(txIEvalContext* aContext,
                                     txAExprResult** aResult) {
  if (!aContext || !requireParams(2, 2, aContext))
    return NS_ERROR_XPATH_BAD_ARGUMENT_COUNT;

  txExecutionState* es =
      static_cast<txExecutionState*>(aContext->getPrivateContext());

  nsAutoString keyQName;
  nsresult rv = mParams[0]->evaluateToString(aContext, keyQName);
  NS_ENSURE_SUCCESS(rv, rv);

  txExpandedName keyName;
  rv = keyName.init(keyQName, mMappings, false);
  NS_ENSURE_SUCCESS(rv, rv);

  RefPtr<txAExprResult> exprResult;
  rv = mParams[1]->evaluate(aContext, getter_AddRefs(exprResult));
  NS_ENSURE_SUCCESS(rv, rv);

  txXPathTreeWalker walker(aContext->getContextNode());
  walker.moveToRoot();

  RefPtr<txNodeSet> res;
  txNodeSet* nodeSet;
  if (exprResult->getResultType() == txAExprResult::NODESET &&
      (nodeSet =
           static_cast<txNodeSet*>(static_cast<txAExprResult*>(exprResult)))
              ->size() > 1) {
    rv = aContext->recycler()->getNodeSet(getter_AddRefs(res));
    NS_ENSURE_SUCCESS(rv, rv);

    int32_t i;
    for (i = 0; i < nodeSet->size(); ++i) {
      nsAutoString val;
      txXPathNodeUtils::appendNodeValue(nodeSet->get(i), val);

      RefPtr<txNodeSet> nodes;
      rv = es->getKeyNodes(keyName, walker.getCurrentPosition(), val, i == 0,
                           getter_AddRefs(nodes));
      NS_ENSURE_SUCCESS(rv, rv);

      res->add(*nodes);
    }
  } else {
    nsAutoString val;
    exprResult->stringValue(val);
    rv = es->getKeyNodes(keyName, walker.getCurrentPosition(), val, true,
                         getter_AddRefs(res));
    NS_ENSURE_SUCCESS(rv, rv);
  }

  *aResult = res;
  NS_ADDREF(*aResult);

  return NS_OK;
}

Expr::ResultType txKeyFunctionCall::getReturnType() { return NODESET_RESULT; }

bool txKeyFunctionCall::isSensitiveTo(ContextSensitivity aContext) {
  return (aContext & NODE_CONTEXT) || argsSensitiveTo(aContext);
}

#ifdef TX_TO_STRING
void txKeyFunctionCall::appendName(nsAString& aDest) {
  aDest.Append(nsGkAtoms::key->GetUTF16String());
}
#endif

/**
 * Hash functions
 */

bool txKeyValueHashEntry::KeyEquals(KeyTypePointer aKey) const {
  return mKey.mKeyName == aKey->mKeyName &&
         mKey.mRootIdentifier == aKey->mRootIdentifier &&
         mKey.mKeyValue.Equals(aKey->mKeyValue);
}

PLDHashNumber txKeyValueHashEntry::HashKey(KeyTypePointer aKey) {
  const txKeyValueHashKey* key = static_cast<const txKeyValueHashKey*>(aKey);

  return AddToHash(HashString(key->mKeyValue), key->mKeyName.mNamespaceID,
                   key->mRootIdentifier, key->mKeyName.mLocalName.get());
}

bool txIndexedKeyHashEntry::KeyEquals(KeyTypePointer aKey) const {
  return mKey.mKeyName == aKey->mKeyName &&
         mKey.mRootIdentifier == aKey->mRootIdentifier;
}

PLDHashNumber txIndexedKeyHashEntry::HashKey(KeyTypePointer aKey) {
  const txIndexedKeyHashKey* key =
      static_cast<const txIndexedKeyHashKey*>(aKey);
  return HashGeneric(key->mKeyName.mNamespaceID, key->mRootIdentifier,
                     key->mKeyName.mLocalName.get());
}

/*
 * Class managing XSLT-keys
 */

nsresult txKeyHash::getKeyNodes(const txExpandedName& aKeyName,
                                const txXPathNode& aRoot,
                                const nsAString& aKeyValue,
                                bool aIndexIfNotFound, txExecutionState& aEs,
                                txNodeSet** aResult) {
  *aResult = nullptr;

  int32_t identifier = txXPathNodeUtils::getUniqueIdentifier(aRoot);

  txKeyValueHashKey valueKey(aKeyName, identifier, aKeyValue);
  txKeyValueHashEntry* valueEntry = mKeyValues.GetEntry(valueKey);
  if (valueEntry) {
    *aResult = valueEntry->mNodeSet;
    NS_ADDREF(*aResult);

    return NS_OK;
  }

  // We didn't find a value. This could either mean that that key has no
  // nodes with that value or that the key hasn't been indexed using this
  // document.

  if (!aIndexIfNotFound) {
    // If aIndexIfNotFound is set then the caller knows this key is
    // indexed, so don't bother investigating.
    *aResult = mEmptyNodeSet;
    NS_ADDREF(*aResult);

    return NS_OK;
  }

  txIndexedKeyHashKey indexKey(aKeyName, identifier);
  txIndexedKeyHashEntry* indexEntry = mIndexedKeys.PutEntry(indexKey);
  NS_ENSURE_TRUE(indexEntry, NS_ERROR_OUT_OF_MEMORY);

  if (indexEntry->mIndexed) {
    // The key was indexed and apparently didn't contain this value so
    // return the empty nodeset.
    *aResult = mEmptyNodeSet;
    NS_ADDREF(*aResult);

    return NS_OK;
  }

  // The key needs to be indexed.
  txXSLKey* xslKey = mKeys.get(aKeyName);
  if (!xslKey) {
    // The key didn't exist, so bail.
    return NS_ERROR_INVALID_ARG;
  }

  nsresult rv = xslKey->indexSubtreeRoot(aRoot, mKeyValues, aEs);
  NS_ENSURE_SUCCESS(rv, rv);

  indexEntry->mIndexed = true;

  // Now that the key is indexed we can get its value.
  valueEntry = mKeyValues.GetEntry(valueKey);
  if (valueEntry) {
    *aResult = valueEntry->mNodeSet;
    NS_ADDREF(*aResult);
  } else {
    *aResult = mEmptyNodeSet;
    NS_ADDREF(*aResult);
  }

  return NS_OK;
}

nsresult txKeyHash::init() {
  mEmptyNodeSet = new txNodeSet(nullptr);

  return NS_OK;
}

/**
 * Adds a match/use pair.
 * @param aMatch  match-pattern
 * @param aUse    use-expression
 * @return false if an error occurred, true otherwise
 */
bool txXSLKey::addKey(UniquePtr<txPattern>&& aMatch, UniquePtr<Expr>&& aUse) {
  if (!aMatch || !aUse) return false;

  Key* key = mKeys.AppendElement();
  if (!key) return false;

  key->matchPattern = std::move(aMatch);
  key->useExpr = std::move(aUse);

  return true;
}

/**
 * Indexes a document and adds it to the hash of key values
 * @param aRoot         Subtree root to index and add
 * @param aKeyValueHash Hash to add values to
 * @param aEs           txExecutionState to use for XPath evaluation
 */
nsresult txXSLKey::indexSubtreeRoot(const txXPathNode& aRoot,
                                    txKeyValueHash& aKeyValueHash,
                                    txExecutionState& aEs) {
  txKeyValueHashKey key(mName, txXPathNodeUtils::getUniqueIdentifier(aRoot),
                        u""_ns);
  return indexTree(aRoot, key, aKeyValueHash, aEs);
}

/**
 * Recursively searches a node, its attributes and its subtree for
 * nodes matching any of the keys match-patterns.
 * @param aNode         Node to search
 * @param aKey          Key to use when adding into the hash
 * @param aKeyValueHash Hash to add values to
 * @param aEs           txExecutionState to use for XPath evaluation
 */
nsresult txXSLKey::indexTree(const txXPathNode& aNode, txKeyValueHashKey& aKey,
                             txKeyValueHash& aKeyValueHash,
                             txExecutionState& aEs) {
  nsresult rv = testNode(aNode, aKey, aKeyValueHash, aEs);
  NS_ENSURE_SUCCESS(rv, rv);

  // check if the node's attributes match
  txXPathTreeWalker walker(aNode);
  if (walker.moveToFirstAttribute()) {
    do {
      rv = testNode(walker.getCurrentPosition(), aKey, aKeyValueHash, aEs);
      NS_ENSURE_SUCCESS(rv, rv);
    } while (walker.moveToNextAttribute());
    walker.moveToParent();
  }

  // check if the node's descendants match
  if (walker.moveToFirstChild()) {
    do {
      rv = indexTree(walker.getCurrentPosition(), aKey, aKeyValueHash, aEs);
      NS_ENSURE_SUCCESS(rv, rv);
    } while (walker.moveToNextSibling());
  }

  return NS_OK;
}

/**
 * Tests one node if it matches any of the keys match-patterns. If
 * the node matches its values are added to the index.
 * @param aNode         Node to test
 * @param aKey          Key to use when adding into the hash
 * @param aKeyValueHash Hash to add values to
 * @param aEs           txExecutionState to use for XPath evaluation
 */
nsresult txXSLKey::testNode(const txXPathNode& aNode, txKeyValueHashKey& aKey,
                            txKeyValueHash& aKeyValueHash,
                            txExecutionState& aEs) {
  nsAutoString val;
  uint32_t currKey, numKeys = mKeys.Length();
  for (currKey = 0; currKey < numKeys; ++currKey) {
    bool matched;
    nsresult rv = mKeys[currKey].matchPattern->matches(aNode, &aEs, matched);
    NS_ENSURE_SUCCESS(rv, rv);

    if (matched) {
      txSingleNodeContext* evalContext = new txSingleNodeContext(aNode, &aEs);
      NS_ENSURE_TRUE(evalContext, NS_ERROR_OUT_OF_MEMORY);

      nsresult rv = aEs.pushEvalContext(evalContext);
      NS_ENSURE_SUCCESS(rv, rv);

      RefPtr<txAExprResult> exprResult;
      rv = mKeys[currKey].useExpr->evaluate(evalContext,
                                            getter_AddRefs(exprResult));

      delete aEs.popEvalContext();
      NS_ENSURE_SUCCESS(rv, rv);

      if (exprResult->getResultType() == txAExprResult::NODESET) {
        txNodeSet* res =
            static_cast<txNodeSet*>(static_cast<txAExprResult*>(exprResult));
        int32_t i;
        for (i = 0; i < res->size(); ++i) {
          val.Truncate();
          txXPathNodeUtils::appendNodeValue(res->get(i), val);

          aKey.mKeyValue.Assign(val);
          txKeyValueHashEntry* entry = aKeyValueHash.PutEntry(aKey);
          NS_ENSURE_TRUE(entry && entry->mNodeSet, NS_ERROR_OUT_OF_MEMORY);

          if (entry->mNodeSet->isEmpty() ||
              entry->mNodeSet->get(entry->mNodeSet->size() - 1) != aNode) {
            entry->mNodeSet->append(aNode);
          }
        }
      } else {
        exprResult->stringValue(val);

        aKey.mKeyValue.Assign(val);
        txKeyValueHashEntry* entry = aKeyValueHash.PutEntry(aKey);
        NS_ENSURE_TRUE(entry && entry->mNodeSet, NS_ERROR_OUT_OF_MEMORY);

        if (entry->mNodeSet->isEmpty() ||
            entry->mNodeSet->get(entry->mNodeSet->size() - 1) != aNode) {
          entry->mNodeSet->append(aNode);
        }
      }
    }
  }

  return NS_OK;
}