Adding upstream version 115.7.0esr.upstream/115.7.0esrupstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 888 insertions, 0 deletions

diff --git a/dom/html/HTMLFormSubmission.cpp b/dom/html/HTMLFormSubmission.cpp
new file mode 100644
index 0000000000..4f42f19716
--- /dev/null
+++ b/dom/html/HTMLFormSubmission.cpp
@@ -0,0 +1,888 @@
+/* -*- 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 "HTMLFormSubmission.h"
+#include "HTMLFormElement.h"
+#include "HTMLFormSubmissionConstants.h"
+#include "nsCOMPtr.h"
+#include "nsComponentManagerUtils.h"
+#include "nsGkAtoms.h"
+#include "nsIFormControl.h"
+#include "nsError.h"
+#include "nsGenericHTMLElement.h"
+#include "nsAttrValueInlines.h"
+#include "nsDirectoryServiceDefs.h"
+#include "nsStringStream.h"
+#include "nsIURI.h"
+#include "nsIURIMutator.h"
+#include "nsIURL.h"
+#include "nsNetUtil.h"
+#include "nsLinebreakConverter.h"
+#include "nsEscape.h"
+#include "nsUnicharUtils.h"
+#include "nsIMultiplexInputStream.h"
+#include "nsIMIMEInputStream.h"
+#include "nsIScriptError.h"
+#include "nsCExternalHandlerService.h"
+#include "nsContentUtils.h"
+
+#include "mozilla/dom/Document.h"
+#include "mozilla/dom/AncestorIterator.h"
+#include "mozilla/dom/Directory.h"
+#include "mozilla/dom/File.h"
+#include "mozilla/StaticPrefs_dom.h"
+#include "mozilla/RandomNum.h"
+
+#include <tuple>
+
+namespace mozilla::dom {
+
+namespace {
+
+void SendJSWarning(Document* aDocument, const char* aWarningName,
+                   const nsTArray<nsString>& aWarningArgs) {
+  nsContentUtils::ReportToConsole(nsIScriptError::warningFlag, "HTML"_ns,
+                                  aDocument, nsContentUtils::eFORMS_PROPERTIES,
+                                  aWarningName, aWarningArgs);
+}
+
+void RetrieveFileName(Blob* aBlob, nsAString& aFilename) {
+  if (!aBlob) {
+    return;
+  }
+
+  RefPtr<File> file = aBlob->ToFile();
+  if (file) {
+    file->GetName(aFilename);
+  }
+}
+
+void RetrieveDirectoryName(Directory* aDirectory, nsAString& aDirname) {
+  MOZ_ASSERT(aDirectory);
+
+  ErrorResult rv;
+  aDirectory->GetName(aDirname, rv);
+  if (NS_WARN_IF(rv.Failed())) {
+    rv.SuppressException();
+    aDirname.Truncate();
+  }
+}
+
+// --------------------------------------------------------------------------
+
+class FSURLEncoded : public EncodingFormSubmission {
+ public:
+  /**
+   * @param aEncoding the character encoding of the form
+   * @param aMethod the method of the submit (either NS_FORM_METHOD_GET or
+   *        NS_FORM_METHOD_POST).
+   */
+  FSURLEncoded(nsIURI* aActionURL, const nsAString& aTarget,
+               NotNull<const Encoding*> aEncoding, int32_t aMethod,
+               Document* aDocument, Element* aSubmitter)
+      : EncodingFormSubmission(aActionURL, aTarget, aEncoding, aSubmitter),
+        mMethod(aMethod),
+        mDocument(aDocument),
+        mWarnedFileControl(false) {}
+
+  virtual nsresult AddNameValuePair(const nsAString& aName,
+                                    const nsAString& aValue) override;
+
+  virtual nsresult AddNameBlobPair(const nsAString& aName,
+                                   Blob* aBlob) override;
+
+  virtual nsresult AddNameDirectoryPair(const nsAString& aName,
+                                        Directory* aDirectory) override;
+
+  virtual nsresult GetEncodedSubmission(nsIURI* aURI,
+                                        nsIInputStream** aPostDataStream,
+                                        nsCOMPtr<nsIURI>& aOutURI) override;
+
+ protected:
+  /**
+   * URL encode a Unicode string by encoding it to bytes, converting linebreaks
+   * properly, and then escaping many bytes as %xx.
+   *
+   * @param aStr the string to encode
+   * @param aEncoded the encoded string [OUT]
+   * @throws NS_ERROR_OUT_OF_MEMORY if we run out of memory
+   */
+  nsresult URLEncode(const nsAString& aStr, nsACString& aEncoded);
+
+ private:
+  /**
+   * The method of the submit (either NS_FORM_METHOD_GET or
+   * NS_FORM_METHOD_POST).
+   */
+  int32_t mMethod;
+
+  /** The query string so far (the part after the ?) */
+  nsCString mQueryString;
+
+  /** The document whose URI to use when reporting errors */
+  nsCOMPtr<Document> mDocument;
+
+  /** Whether or not we have warned about a file control not being submitted */
+  bool mWarnedFileControl;
+};
+
+nsresult FSURLEncoded::AddNameValuePair(const nsAString& aName,
+                                        const nsAString& aValue) {
+  // Encode value
+  nsCString convValue;
+  nsresult rv = URLEncode(aValue, convValue);
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  // Encode name
+  nsAutoCString convName;
+  rv = URLEncode(aName, convName);
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  // Append data to string
+  if (mQueryString.IsEmpty()) {
+    mQueryString += convName + "="_ns + convValue;
+  } else {
+    mQueryString += "&"_ns + convName + "="_ns + convValue;
+  }
+
+  return NS_OK;
+}
+
+nsresult FSURLEncoded::AddNameBlobPair(const nsAString& aName, Blob* aBlob) {
+  if (!mWarnedFileControl) {
+    SendJSWarning(mDocument, "ForgotFileEnctypeWarning", nsTArray<nsString>());
+    mWarnedFileControl = true;
+  }
+
+  nsAutoString filename;
+  RetrieveFileName(aBlob, filename);
+  return AddNameValuePair(aName, filename);
+}
+
+nsresult FSURLEncoded::AddNameDirectoryPair(const nsAString& aName,
+                                            Directory* aDirectory) {
+  // No warning about because Directory objects are never sent via form.
+
+  nsAutoString dirname;
+  RetrieveDirectoryName(aDirectory, dirname);
+  return AddNameValuePair(aName, dirname);
+}
+
+void HandleMailtoSubject(nsCString& aPath) {
+  // Walk through the string and see if we have a subject already.
+  bool hasSubject = false;
+  bool hasParams = false;
+  int32_t paramSep = aPath.FindChar('?');
+  while (paramSep != kNotFound && paramSep < (int32_t)aPath.Length()) {
+    hasParams = true;
+
+    // Get the end of the name at the = op.  If it is *after* the next &,
+    // assume that someone made a parameter without an = in it
+    int32_t nameEnd = aPath.FindChar('=', paramSep + 1);
+    int32_t nextParamSep = aPath.FindChar('&', paramSep + 1);
+    if (nextParamSep == kNotFound) {
+      nextParamSep = aPath.Length();
+    }
+
+    // If the = op is after the &, this parameter is a name without value.
+    // If there is no = op, same thing.
+    if (nameEnd == kNotFound || nextParamSep < nameEnd) {
+      nameEnd = nextParamSep;
+    }
+
+    if (nameEnd != kNotFound) {
+      if (Substring(aPath, paramSep + 1, nameEnd - (paramSep + 1))
+              .LowerCaseEqualsLiteral("subject")) {
+        hasSubject = true;
+        break;
+      }
+    }
+
+    paramSep = nextParamSep;
+  }
+
+  // If there is no subject, append a preformed subject to the mailto line
+  if (!hasSubject) {
+    if (hasParams) {
+      aPath.Append('&');
+    } else {
+      aPath.Append('?');
+    }
+
+    // Get the default subject
+    nsAutoString brandName;
+    nsresult rv = nsContentUtils::GetLocalizedString(
+        nsContentUtils::eBRAND_PROPERTIES, "brandShortName", brandName);
+    if (NS_FAILED(rv)) return;
+    nsAutoString subjectStr;
+    rv = nsContentUtils::FormatLocalizedString(
+        subjectStr, nsContentUtils::eFORMS_PROPERTIES, "DefaultFormSubject",
+        brandName);
+    if (NS_FAILED(rv)) return;
+    aPath.AppendLiteral("subject=");
+    nsCString subjectStrEscaped;
+    rv = NS_EscapeURL(NS_ConvertUTF16toUTF8(subjectStr), esc_Query,
+                      subjectStrEscaped, mozilla::fallible);
+    if (NS_FAILED(rv)) return;
+
+    aPath.Append(subjectStrEscaped);
+  }
+}
+
+nsresult FSURLEncoded::GetEncodedSubmission(nsIURI* aURI,
+                                            nsIInputStream** aPostDataStream,
+                                            nsCOMPtr<nsIURI>& aOutURI) {
+  nsresult rv = NS_OK;
+  aOutURI = aURI;
+
+  *aPostDataStream = nullptr;
+
+  if (mMethod == NS_FORM_METHOD_POST) {
+    if (aURI->SchemeIs("mailto")) {
+      nsAutoCString path;
+      rv = aURI->GetPathQueryRef(path);
+      NS_ENSURE_SUCCESS(rv, rv);
+
+      HandleMailtoSubject(path);
+
+      // Append the body to and force-plain-text args to the mailto line
+      nsAutoCString escapedBody;
+      if (NS_WARN_IF(!NS_Escape(mQueryString, escapedBody, url_XAlphas))) {
+        return NS_ERROR_OUT_OF_MEMORY;
+      }
+
+      path += "&force-plain-text=Y&body="_ns + escapedBody;
+
+      return NS_MutateURI(aURI).SetPathQueryRef(path).Finalize(aOutURI);
+    } else {
+      nsCOMPtr<nsIInputStream> dataStream;
+      rv = NS_NewCStringInputStream(getter_AddRefs(dataStream),
+                                    std::move(mQueryString));
+      NS_ENSURE_SUCCESS(rv, rv);
+      mQueryString.Truncate();
+
+      nsCOMPtr<nsIMIMEInputStream> mimeStream(
+          do_CreateInstance("@mozilla.org/network/mime-input-stream;1", &rv));
+      NS_ENSURE_SUCCESS(rv, rv);
+
+      mimeStream->AddHeader("Content-Type",
+                            "application/x-www-form-urlencoded");
+      mimeStream->SetData(dataStream);
+
+      mimeStream.forget(aPostDataStream);
+    }
+
+  } else {
+    // Get the full query string
+    if (aURI->SchemeIs("javascript")) {
+      return NS_OK;
+    }
+
+    nsCOMPtr<nsIURL> url = do_QueryInterface(aURI);
+    if (url) {
+      // Make sure that we end up with a query component in the URL.  If
+      // mQueryString is empty, nsIURI::SetQuery() will remove the query
+      // component, which is not what we want.
+      rv = NS_MutateURI(aURI)
+               .SetQuery(mQueryString.IsEmpty() ? "?"_ns : mQueryString)
+               .Finalize(aOutURI);
+    } else {
+      nsAutoCString path;
+      rv = aURI->GetPathQueryRef(path);
+      NS_ENSURE_SUCCESS(rv, rv);
+      // Bug 42616: Trim off named anchor and save it to add later
+      int32_t namedAnchorPos = path.FindChar('#');
+      nsAutoCString namedAnchor;
+      if (kNotFound != namedAnchorPos) {
+        path.Right(namedAnchor, (path.Length() - namedAnchorPos));
+        path.Truncate(namedAnchorPos);
+      }
+
+      // Chop off old query string (bug 25330, 57333)
+      // Only do this for GET not POST (bug 41585)
+      int32_t queryStart = path.FindChar('?');
+      if (kNotFound != queryStart) {
+        path.Truncate(queryStart);
+      }
+
+      path.Append('?');
+      // Bug 42616: Add named anchor to end after query string
+      path.Append(mQueryString + namedAnchor);
+
+      rv = NS_MutateURI(aURI).SetPathQueryRef(path).Finalize(aOutURI);
+    }
+  }
+
+  return rv;
+}
+
+// i18n helper routines
+nsresult FSURLEncoded::URLEncode(const nsAString& aStr, nsACString& aEncoded) {
+  nsAutoCString encodedBuf;
+  // We encode with eValueEncode because the urlencoded format needs the newline
+  // normalizations but percent-escapes characters that eNameEncode doesn't,
+  // so calling NS_Escape would still be needed.
+  nsresult rv = EncodeVal(aStr, encodedBuf, EncodeType::eValueEncode);
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  if (NS_WARN_IF(!NS_Escape(encodedBuf, aEncoded, url_XPAlphas))) {
+    return NS_ERROR_OUT_OF_MEMORY;
+  }
+
+  return NS_OK;
+}
+
+}  // anonymous namespace
+
+// --------------------------------------------------------------------------
+
+FSMultipartFormData::FSMultipartFormData(nsIURI* aActionURL,
+                                         const nsAString& aTarget,
+                                         NotNull<const Encoding*> aEncoding,
+                                         Element* aSubmitter)
+    : EncodingFormSubmission(aActionURL, aTarget, aEncoding, aSubmitter) {
+  mPostData = do_CreateInstance("@mozilla.org/io/multiplex-input-stream;1");
+
+  nsCOMPtr<nsIInputStream> inputStream = do_QueryInterface(mPostData);
+  MOZ_ASSERT(SameCOMIdentity(mPostData, inputStream));
+  mPostDataStream = inputStream;
+
+  mTotalLength = 0;
+
+  mBoundary.AssignLiteral("---------------------------");
+  mBoundary.AppendInt(static_cast<uint32_t>(mozilla::RandomUint64OrDie()));
+  mBoundary.AppendInt(static_cast<uint32_t>(mozilla::RandomUint64OrDie()));
+  mBoundary.AppendInt(static_cast<uint32_t>(mozilla::RandomUint64OrDie()));
+}
+
+FSMultipartFormData::~FSMultipartFormData() {
+  NS_ASSERTION(mPostDataChunk.IsEmpty(), "Left unsubmitted data");
+}
+
+nsIInputStream* FSMultipartFormData::GetSubmissionBody(
+    uint64_t* aContentLength) {
+  // Finish data
+  mPostDataChunk += "--"_ns + mBoundary + nsLiteralCString("--" CRLF);
+
+  // Add final data input stream
+  AddPostDataStream();
+
+  *aContentLength = mTotalLength;
+  return mPostDataStream;
+}
+
+nsresult FSMultipartFormData::AddNameValuePair(const nsAString& aName,
+                                               const nsAString& aValue) {
+  nsAutoCString encodedVal;
+  nsresult rv = EncodeVal(aValue, encodedVal, EncodeType::eValueEncode);
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  nsAutoCString nameStr;
+  rv = EncodeVal(aName, nameStr, EncodeType::eNameEncode);
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  // Make MIME block for name/value pair
+
+  mPostDataChunk += "--"_ns + mBoundary + nsLiteralCString(CRLF) +
+                    "Content-Disposition: form-data; name=\""_ns + nameStr +
+                    nsLiteralCString("\"" CRLF CRLF) + encodedVal +
+                    nsLiteralCString(CRLF);
+
+  return NS_OK;
+}
+
+nsresult FSMultipartFormData::AddNameBlobPair(const nsAString& aName,
+                                              Blob* aBlob) {
+  MOZ_ASSERT(aBlob);
+
+  // Encode the control name
+  nsAutoCString nameStr;
+  nsresult rv = EncodeVal(aName, nameStr, EncodeType::eNameEncode);
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  ErrorResult error;
+
+  uint64_t size = 0;
+  nsAutoCString filename;
+  nsAutoCString contentType;
+  nsCOMPtr<nsIInputStream> fileStream;
+  nsAutoString filename16;
+
+  RefPtr<File> file = aBlob->ToFile();
+  if (file) {
+    nsAutoString relativePath;
+    file->GetRelativePath(relativePath);
+    if (StaticPrefs::dom_webkitBlink_dirPicker_enabled() &&
+        !relativePath.IsEmpty()) {
+      filename16 = relativePath;
+    }
+
+    if (filename16.IsEmpty()) {
+      RetrieveFileName(aBlob, filename16);
+    }
+  }
+
+  rv = EncodeVal(filename16, filename, EncodeType::eFilenameEncode);
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  // Get content type
+  nsAutoString contentType16;
+  aBlob->GetType(contentType16);
+  if (contentType16.IsEmpty()) {
+    contentType16.AssignLiteral("application/octet-stream");
+  }
+
+  NS_ConvertUTF16toUTF8 contentType8(contentType16);
+  int32_t convertedBufLength = 0;
+  char* convertedBuf = nsLinebreakConverter::ConvertLineBreaks(
+      contentType8.get(), nsLinebreakConverter::eLinebreakAny,
+      nsLinebreakConverter::eLinebreakSpace, contentType8.Length(),
+      &convertedBufLength);
+  contentType.Adopt(convertedBuf, convertedBufLength);
+
+  // Get input stream
+  aBlob->CreateInputStream(getter_AddRefs(fileStream), error);
+  if (NS_WARN_IF(error.Failed())) {
+    return error.StealNSResult();
+  }
+
+  // Get size
+  size = aBlob->GetSize(error);
+  if (error.Failed()) {
+    error.SuppressException();
+    fileStream = nullptr;
+  }
+
+  if (fileStream) {
+    // Create buffered stream (for efficiency)
+    nsCOMPtr<nsIInputStream> bufferedStream;
+    rv = NS_NewBufferedInputStream(getter_AddRefs(bufferedStream),
+                                   fileStream.forget(), 8192);
+    NS_ENSURE_SUCCESS(rv, rv);
+
+    fileStream = bufferedStream;
+  }
+
+  AddDataChunk(nameStr, filename, contentType, fileStream, size);
+  return NS_OK;
+}
+
+nsresult FSMultipartFormData::AddNameDirectoryPair(const nsAString& aName,
+                                                   Directory* aDirectory) {
+  if (!StaticPrefs::dom_webkitBlink_dirPicker_enabled()) {
+    return NS_OK;
+  }
+
+  // Encode the control name
+  nsAutoCString nameStr;
+  nsresult rv = EncodeVal(aName, nameStr, EncodeType::eNameEncode);
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  nsAutoCString dirname;
+  nsAutoString dirname16;
+
+  ErrorResult error;
+  nsAutoString path;
+  aDirectory->GetPath(path, error);
+  if (NS_WARN_IF(error.Failed())) {
+    error.SuppressException();
+  } else {
+    dirname16 = path;
+  }
+
+  if (dirname16.IsEmpty()) {
+    RetrieveDirectoryName(aDirectory, dirname16);
+  }
+
+  rv = EncodeVal(dirname16, dirname, EncodeType::eFilenameEncode);
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  AddDataChunk(nameStr, dirname, "application/octet-stream"_ns, nullptr, 0);
+  return NS_OK;
+}
+
+void FSMultipartFormData::AddDataChunk(const nsACString& aName,
+                                       const nsACString& aFilename,
+                                       const nsACString& aContentType,
+                                       nsIInputStream* aInputStream,
+                                       uint64_t aInputStreamSize) {
+  //
+  // Make MIME block for name/value pair
+  //
+  // more appropriate than always using binary?
+  mPostDataChunk += "--"_ns + mBoundary + nsLiteralCString(CRLF);
+  mPostDataChunk += "Content-Disposition: form-data; name=\""_ns + aName +
+                    "\"; filename=\""_ns + aFilename +
+                    nsLiteralCString("\"" CRLF) + "Content-Type: "_ns +
+                    aContentType + nsLiteralCString(CRLF CRLF);
+
+  // We should not try to append an invalid stream. That will happen for example
+  // if we try to update a file that actually do not exist.
+  if (aInputStream) {
+    // We need to dump the data up to this point into the POST data stream
+    // here, since we're about to add the file input stream
+    AddPostDataStream();
+
+    mPostData->AppendStream(aInputStream);
+    mTotalLength += aInputStreamSize;
+  }
+
+  // CRLF after file
+  mPostDataChunk.AppendLiteral(CRLF);
+}
+
+nsresult FSMultipartFormData::GetEncodedSubmission(
+    nsIURI* aURI, nsIInputStream** aPostDataStream, nsCOMPtr<nsIURI>& aOutURI) {
+  nsresult rv;
+  aOutURI = aURI;
+
+  // Make header
+  nsCOMPtr<nsIMIMEInputStream> mimeStream =
+      do_CreateInstance("@mozilla.org/network/mime-input-stream;1", &rv);
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  nsAutoCString contentType;
+  GetContentType(contentType);
+  mimeStream->AddHeader("Content-Type", contentType.get());
+
+  uint64_t bodySize;
+  mimeStream->SetData(GetSubmissionBody(&bodySize));
+
+  mimeStream.forget(aPostDataStream);
+
+  return NS_OK;
+}
+
+nsresult FSMultipartFormData::AddPostDataStream() {
+  nsresult rv = NS_OK;
+
+  nsCOMPtr<nsIInputStream> postDataChunkStream;
+  rv = NS_NewCStringInputStream(getter_AddRefs(postDataChunkStream),
+                                mPostDataChunk);
+  NS_ASSERTION(postDataChunkStream, "Could not open a stream for POST!");
+  if (postDataChunkStream) {
+    mPostData->AppendStream(postDataChunkStream);
+    mTotalLength += mPostDataChunk.Length();
+  }
+
+  mPostDataChunk.Truncate();
+
+  return rv;
+}
+
+// --------------------------------------------------------------------------
+
+namespace {
+
+class FSTextPlain : public EncodingFormSubmission {
+ public:
+  FSTextPlain(nsIURI* aActionURL, const nsAString& aTarget,
+              NotNull<const Encoding*> aEncoding, Element* aSubmitter)
+      : EncodingFormSubmission(aActionURL, aTarget, aEncoding, aSubmitter) {}
+
+  virtual nsresult AddNameValuePair(const nsAString& aName,
+                                    const nsAString& aValue) override;
+
+  virtual nsresult AddNameBlobPair(const nsAString& aName,
+                                   Blob* aBlob) override;
+
+  virtual nsresult AddNameDirectoryPair(const nsAString& aName,
+                                        Directory* aDirectory) override;
+
+  virtual nsresult GetEncodedSubmission(nsIURI* aURI,
+                                        nsIInputStream** aPostDataStream,
+                                        nsCOMPtr<nsIURI>& aOutURI) override;
+
+ private:
+  nsString mBody;
+};
+
+nsresult FSTextPlain::AddNameValuePair(const nsAString& aName,
+                                       const nsAString& aValue) {
+  // XXX This won't work well with a name like "a=b" or "a\nb" but I suppose
+  // text/plain doesn't care about that.  Parsers aren't built for escaped
+  // values so we'll have to live with it.
+  mBody.Append(aName + u"="_ns + aValue + NS_LITERAL_STRING_FROM_CSTRING(CRLF));
+
+  return NS_OK;
+}
+
+nsresult FSTextPlain::AddNameBlobPair(const nsAString& aName, Blob* aBlob) {
+  nsAutoString filename;
+  RetrieveFileName(aBlob, filename);
+  AddNameValuePair(aName, filename);
+  return NS_OK;
+}
+
+nsresult FSTextPlain::AddNameDirectoryPair(const nsAString& aName,
+                                           Directory* aDirectory) {
+  nsAutoString dirname;
+  RetrieveDirectoryName(aDirectory, dirname);
+  AddNameValuePair(aName, dirname);
+  return NS_OK;
+}
+
+nsresult FSTextPlain::GetEncodedSubmission(nsIURI* aURI,
+                                           nsIInputStream** aPostDataStream,
+                                           nsCOMPtr<nsIURI>& aOutURI) {
+  nsresult rv = NS_OK;
+  aOutURI = aURI;
+
+  *aPostDataStream = nullptr;
+
+  // XXX HACK We are using the standard URL mechanism to give the body to the
+  // mailer instead of passing the post data stream to it, since that sounds
+  // hard.
+  if (aURI->SchemeIs("mailto")) {
+    nsAutoCString path;
+    rv = aURI->GetPathQueryRef(path);
+    NS_ENSURE_SUCCESS(rv, rv);
+
+    HandleMailtoSubject(path);
+
+    // Append the body to and force-plain-text args to the mailto line
+    nsAutoCString escapedBody;
+    if (NS_WARN_IF(!NS_Escape(NS_ConvertUTF16toUTF8(mBody), escapedBody,
+                              url_XAlphas))) {
+      return NS_ERROR_OUT_OF_MEMORY;
+    }
+
+    path += "&force-plain-text=Y&body="_ns + escapedBody;
+
+    rv = NS_MutateURI(aURI).SetPathQueryRef(path).Finalize(aOutURI);
+  } else {
+    // Create data stream.
+    // We use eValueEncode to send the data through the charset encoder and to
+    // normalize linebreaks to use the "standard net" format (\r\n), but not
+    // perform any other escaping. This means that names and values which
+    // contain '=' or newlines are potentially ambiguously encoded, but that is
+    // how text/plain is specced.
+    nsCString cbody;
+    EncodeVal(mBody, cbody, EncodeType::eValueEncode);
+
+    nsCOMPtr<nsIInputStream> bodyStream;
+    rv = NS_NewCStringInputStream(getter_AddRefs(bodyStream), std::move(cbody));
+    if (!bodyStream) {
+      return NS_ERROR_OUT_OF_MEMORY;
+    }
+
+    // Create mime stream with headers and such
+    nsCOMPtr<nsIMIMEInputStream> mimeStream =
+        do_CreateInstance("@mozilla.org/network/mime-input-stream;1", &rv);
+    NS_ENSURE_SUCCESS(rv, rv);
+
+    mimeStream->AddHeader("Content-Type", "text/plain");
+    mimeStream->SetData(bodyStream);
+    mimeStream.forget(aPostDataStream);
+  }
+
+  return rv;
+}
+
+}  // anonymous namespace
+
+// --------------------------------------------------------------------------
+
+HTMLFormSubmission::HTMLFormSubmission(
+    nsIURI* aActionURL, const nsAString& aTarget,
+    mozilla::NotNull<const mozilla::Encoding*> aEncoding)
+    : mActionURL(aActionURL),
+      mTarget(aTarget),
+      mEncoding(aEncoding),
+      mInitiatedFromUserInput(UserActivation::IsHandlingUserInput()) {
+  MOZ_COUNT_CTOR(HTMLFormSubmission);
+}
+
+EncodingFormSubmission::EncodingFormSubmission(
+    nsIURI* aActionURL, const nsAString& aTarget,
+    NotNull<const Encoding*> aEncoding, Element* aSubmitter)
+    : HTMLFormSubmission(aActionURL, aTarget, aEncoding) {
+  if (!aEncoding->CanEncodeEverything()) {
+    nsAutoCString name;
+    aEncoding->Name(name);
+    AutoTArray<nsString, 1> args;
+    CopyUTF8toUTF16(name, *args.AppendElement());
+    SendJSWarning(aSubmitter ? aSubmitter->GetOwnerDocument() : nullptr,
+                  "CannotEncodeAllUnicode", args);
+  }
+}
+
+EncodingFormSubmission::~EncodingFormSubmission() = default;
+
+// i18n helper routines
+nsresult EncodingFormSubmission::EncodeVal(const nsAString& aStr,
+                                           nsCString& aOut,
+                                           EncodeType aEncodeType) {
+  nsresult rv;
+  std::tie(rv, std::ignore) = mEncoding->Encode(aStr, aOut);
+  if (NS_FAILED(rv)) {
+    return rv;
+  }
+
+  if (aEncodeType != EncodeType::eFilenameEncode) {
+    // Normalize newlines
+    int32_t convertedBufLength = 0;
+    char* convertedBuf = nsLinebreakConverter::ConvertLineBreaks(
+        aOut.get(), nsLinebreakConverter::eLinebreakAny,
+        nsLinebreakConverter::eLinebreakNet, (int32_t)aOut.Length(),
+        &convertedBufLength);
+    aOut.Adopt(convertedBuf, convertedBufLength);
+  }
+
+  if (aEncodeType != EncodeType::eValueEncode) {
+    // Percent-escape LF, CR and double quotes.
+    int32_t offset = 0;
+    while ((offset = aOut.FindCharInSet("\n\r\"", offset)) != kNotFound) {
+      if (aOut[offset] == '\n') {
+        aOut.ReplaceLiteral(offset, 1, "%0A");
+      } else if (aOut[offset] == '\r') {
+        aOut.ReplaceLiteral(offset, 1, "%0D");
+      } else if (aOut[offset] == '"') {
+        aOut.ReplaceLiteral(offset, 1, "%22");
+      } else {
+        MOZ_ASSERT(false);
+        offset++;
+        continue;
+      }
+    }
+  }
+
+  return NS_OK;
+}
+
+// --------------------------------------------------------------------------
+
+namespace {
+
+void GetEnumAttr(nsGenericHTMLElement* aContent, nsAtom* atom,
+                 int32_t* aValue) {
+  const nsAttrValue* value = aContent->GetParsedAttr(atom);
+  if (value && value->Type() == nsAttrValue::eEnum) {
+    *aValue = value->GetEnumValue();
+  }
+}
+
+}  // anonymous namespace
+
+/* static */
+nsresult HTMLFormSubmission::GetFromForm(HTMLFormElement* aForm,
+                                         nsGenericHTMLElement* aSubmitter,
+                                         NotNull<const Encoding*>& aEncoding,
+                                         HTMLFormSubmission** aFormSubmission) {
+  // Get all the information necessary to encode the form data
+  NS_ASSERTION(aForm->GetComposedDoc(),
+               "Should have doc if we're building submission!");
+
+  nsresult rv;
+
+  // Get action
+  nsCOMPtr<nsIURI> actionURL;
+  rv = aForm->GetActionURL(getter_AddRefs(actionURL), aSubmitter);
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  // Check if CSP allows this form-action
+  nsCOMPtr<nsIContentSecurityPolicy> csp = aForm->GetCsp();
+  if (csp) {
+    bool permitsFormAction = true;
+
+    // form-action is only enforced if explicitly defined in the
+    // policy - do *not* consult default-src, see:
+    // http://www.w3.org/TR/CSP2/#directive-default-src
+    rv = csp->Permits(aForm, nullptr /* nsICSPEventListener */, actionURL,
+                      nsIContentSecurityPolicy::FORM_ACTION_DIRECTIVE,
+                      true /* aSpecific */, true /* aSendViolationReports */,
+                      &permitsFormAction);
+    NS_ENSURE_SUCCESS(rv, rv);
+    if (!permitsFormAction) {
+      return NS_ERROR_CSP_FORM_ACTION_VIOLATION;
+    }
+  }
+
+  // Get target
+  // The target is the submitter element formtarget attribute if the element
+  // is a submit control and has such an attribute.
+  // Otherwise, the target is the form owner's target attribute,
+  // if it has such an attribute.
+  // Finally, if one of the child nodes of the head element is a base element
+  // with a target attribute, then the value of the target attribute of the
+  // first such base element; or, if there is no such element, the empty string.
+  nsAutoString target;
+  if (!(aSubmitter && aSubmitter->GetAttr(kNameSpaceID_None,
+                                          nsGkAtoms::formtarget, target)) &&
+      !aForm->GetAttr(kNameSpaceID_None, nsGkAtoms::target, target)) {
+    aForm->GetBaseTarget(target);
+  }
+
+  // Get encoding type (default: urlencoded)
+  int32_t enctype = NS_FORM_ENCTYPE_URLENCODED;
+  if (aSubmitter &&
+      aSubmitter->HasAttr(kNameSpaceID_None, nsGkAtoms::formenctype)) {
+    GetEnumAttr(aSubmitter, nsGkAtoms::formenctype, &enctype);
+  } else {
+    GetEnumAttr(aForm, nsGkAtoms::enctype, &enctype);
+  }
+
+  // Get method (default: GET)
+  int32_t method = NS_FORM_METHOD_GET;
+  if (aSubmitter &&
+      aSubmitter->HasAttr(kNameSpaceID_None, nsGkAtoms::formmethod)) {
+    GetEnumAttr(aSubmitter, nsGkAtoms::formmethod, &method);
+  } else {
+    GetEnumAttr(aForm, nsGkAtoms::method, &method);
+  }
+
+  if (method == NS_FORM_METHOD_DIALOG) {
+    HTMLDialogElement* dialog = aForm->FirstAncestorOfType<HTMLDialogElement>();
+
+    // If there isn't one, or if it does not have an open attribute, do
+    // nothing.
+    if (!dialog || !dialog->Open()) {
+      return NS_ERROR_FAILURE;
+    }
+
+    nsAutoString result;
+    if (aSubmitter) {
+      aSubmitter->ResultForDialogSubmit(result);
+    }
+    *aFormSubmission =
+        new DialogFormSubmission(result, actionURL, target, aEncoding, dialog);
+    return NS_OK;
+  }
+
+  MOZ_ASSERT(method != NS_FORM_METHOD_DIALOG);
+
+  // Choose encoder
+  if (method == NS_FORM_METHOD_POST && enctype == NS_FORM_ENCTYPE_MULTIPART) {
+    *aFormSubmission =
+        new FSMultipartFormData(actionURL, target, aEncoding, aSubmitter);
+  } else if (method == NS_FORM_METHOD_POST &&
+             enctype == NS_FORM_ENCTYPE_TEXTPLAIN) {
+    *aFormSubmission =
+        new FSTextPlain(actionURL, target, aEncoding, aSubmitter);
+  } else {
+    Document* doc = aForm->OwnerDoc();
+    if (enctype == NS_FORM_ENCTYPE_MULTIPART ||
+        enctype == NS_FORM_ENCTYPE_TEXTPLAIN) {
+      AutoTArray<nsString, 1> args;
+      nsString& enctypeStr = *args.AppendElement();
+      if (aSubmitter &&
+          aSubmitter->HasAttr(kNameSpaceID_None, nsGkAtoms::formenctype)) {
+        aSubmitter->GetAttr(kNameSpaceID_None, nsGkAtoms::formenctype,
+                            enctypeStr);
+      } else {
+        aForm->GetAttr(kNameSpaceID_None, nsGkAtoms::enctype, enctypeStr);
+      }
+
+      SendJSWarning(doc, "ForgotPostWarning", args);
+    }
+    *aFormSubmission =
+        new FSURLEncoded(actionURL, target, aEncoding, method, doc, aSubmitter);
+  }
+
+  return NS_OK;
+}
+
+}  // namespace mozilla::dom