Mozilla/mozilla/content/base/src/nsDOMSerializer.cpp

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 * for the specific language governing rights and limitations under the
 * License.
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 * The Original Code is mozilla.org code.
 *
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 * Contributor(s):
 *
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#include "nsDOMSerializer.h"
#include "nsIDOMNode.h"
#include "nsIDOMClassInfo.h"
#include "nsIOutputStream.h"
#include "nsIDocument.h"
#include "nsIDOMDocument.h"
#include "nsIDocumentEncoder.h"
#include "nsIComponentManager.h"
#include "nsIContentSerializer.h"
#include "nsString.h"
#include "nsReadableUtils.h"

#include "nsIJSContextStack.h"
#include "nsIScriptSecurityManager.h"
#include "nsIURI.h"

nsDOMSerializer::nsDOMSerializer()
{
}

nsDOMSerializer::~nsDOMSerializer()
{
}


// QueryInterface implementation for nsDOMSerializer
NS_INTERFACE_MAP_BEGIN(nsDOMSerializer)
  NS_INTERFACE_MAP_ENTRY(nsISupports)
  NS_INTERFACE_MAP_ENTRY(nsIDOMSerializer)
  NS_INTERFACE_MAP_ENTRY_EXTERNAL_DOM_CLASSINFO(XMLSerializer)
NS_INTERFACE_MAP_END


NS_IMPL_ADDREF(nsDOMSerializer)
NS_IMPL_RELEASE(nsDOMSerializer)


static nsresult SetUpEncoder(nsIDOMNode *aRoot, const char* aCharset, nsIDocumentEncoder **aEncoder)
{
  *aEncoder = nsnull;
   
  nsresult rv;
  nsCOMPtr<nsIDocumentEncoder> encoder(do_CreateInstance(NS_DOC_ENCODER_CONTRACTID_BASE "text/xml",&rv));
  if (NS_FAILED(rv))
    return rv;

  PRBool entireDocument = PR_TRUE;
  nsCOMPtr<nsIDocument> document(do_QueryInterface(aRoot));
  if (!document) {
    entireDocument = PR_FALSE;
    nsCOMPtr<nsIDOMDocument> domDoc;
    rv = aRoot->GetOwnerDocument(getter_AddRefs(domDoc));
    if (NS_FAILED(rv))
      return rv;
    document = do_QueryInterface(domDoc);
  }

  // This method will fail if no document
  rv = encoder->Init(document,NS_LITERAL_STRING("text/xml"),nsIDocumentEncoder::OutputEncodeBasicEntities);
  if (NS_FAILED(rv))
    return rv;

  nsCAutoString charset;
  if (aCharset) {
    charset = aCharset;
  } else {
    rv = document->GetDocumentCharacterSet(charset);
    if (NS_FAILED(rv))
      return rv;
  }
  rv = encoder->SetCharset(charset);
  if (NS_FAILED(rv))
    return rv;

  // If we are working on the entire document we do not need to specify which part to serialize
  if (!entireDocument) {
    rv = encoder->SetNode(aRoot);
  }

  if (NS_SUCCEEDED(rv)) {
    *aEncoder = encoder.get();
    NS_ADDREF(*aEncoder);
  }

  return rv;
}

nsresult CheckSameOrigin(nsIDOMNode *aRoot)
{
  // Get JSContext from stack.
  nsCOMPtr<nsIJSContextStack> stack =
    do_GetService("@mozilla.org/js/xpc/ContextStack;1");

  JSContext *cx = nsnull;
  nsresult rv = NS_OK;

  if (stack) {
    rv = stack->Peek(&cx);
    NS_ENSURE_SUCCESS(rv, rv);
  }

  if (cx) {
    // We're called from script, make sure the caller and the root are
    // from the same origin...

    nsCOMPtr<nsIDOMDocument> owner_doc(do_QueryInterface(aRoot));

    if (!owner_doc) {
      aRoot->GetOwnerDocument(getter_AddRefs(owner_doc));
    }

    nsCOMPtr<nsIDocument> doc(do_QueryInterface(owner_doc));

    if (doc) {
      nsCOMPtr<nsIPrincipal> principal;
      nsCOMPtr<nsIURI> root_uri;

      doc->GetPrincipal(getter_AddRefs(principal));

      if (principal) {
        principal->GetURI(getter_AddRefs(root_uri));
      }

      if (root_uri) {
        nsCOMPtr<nsIScriptSecurityManager> secMan = 
          do_GetService(NS_SCRIPTSECURITYMANAGER_CONTRACTID, &rv);
        NS_ENSURE_SUCCESS(rv, rv);

        rv = secMan->CheckSameOrigin(cx, root_uri);

        if (NS_FAILED(rv)) {
          // The node that's being serialized comes from a different
          // origin than the calling script comes from...

          return rv;
        }
      }
    }      
  }

  return NS_OK;
}

NS_IMETHODIMP
nsDOMSerializer::SerializeToString(nsIDOMNode *aRoot, PRUnichar **_retval)
{
  NS_ENSURE_ARG_POINTER(aRoot);
  NS_ENSURE_ARG_POINTER(_retval);  
  
  *_retval = nsnull;

  nsresult rv = CheckSameOrigin(aRoot);
  if (NS_FAILED(rv))
    return rv;

  nsCOMPtr<nsIDocumentEncoder> encoder;
  rv = SetUpEncoder(aRoot, nsnull, getter_AddRefs(encoder));
  if (NS_FAILED(rv))
    return rv;

  nsAutoString str;
  rv = encoder->EncodeToString(str);
  if (NS_FAILED(rv))
    return rv;

  *_retval = ToNewUnicode(str);
  if (!*_retval)
    return NS_ERROR_OUT_OF_MEMORY;

  return NS_OK;
}

NS_IMETHODIMP
nsDOMSerializer::SerializeToStream(nsIDOMNode *aRoot, 
                                   nsIOutputStream *aStream, 
                                   const char *aCharset)
{
  NS_ENSURE_ARG_POINTER(aRoot);
  NS_ENSURE_ARG_POINTER(aStream);
  // The charset arg can be null, in which case we get the document's
  // charset and use that when serializing.

  nsresult rv = CheckSameOrigin(aRoot);
  if (NS_FAILED(rv))
    return rv;

  nsCOMPtr<nsIDocumentEncoder> encoder;
  rv = SetUpEncoder(aRoot, aCharset, getter_AddRefs(encoder));
  if (NS_FAILED(rv))
    return rv;

  return encoder->EncodeToStream(aStream);
}