Adding upstream version 110.0.1.upstream/110.0.1upstream

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

7 files changed, 1072 insertions, 0 deletions

diff --git a/dom/plugins/base/moz.build b/dom/plugins/base/moz.build
new file mode 100644
index 0000000000..1e13483336
--- /dev/null
+++ b/dom/plugins/base/moz.build
@@ -0,0 +1,45 @@
+# -*- Mode: python; indent-tabs-mode: nil; tab-width: 40 -*-
+# vim: set filetype=python:
+# 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/.
+
+XPIDL_SOURCES += [
+    "nsIPluginTag.idl",
+]
+
+XPIDL_MODULE = "plugin"
+
+EXPORTS += [
+    "nsPluginHost.h",
+    "nsPluginLogging.h",
+    "nsPluginTags.h",
+]
+
+UNIFIED_SOURCES += [
+    "nsPluginHost.cpp",
+    "nsPluginTags.cpp",
+]
+
+LOCAL_INCLUDES += [
+    "/dom/base",
+    "/gfx/cairo/cairo/src",
+    "/layout/generic",
+    "/layout/xul",
+    "/netwerk/base",
+    "/widget",
+    "/widget/cocoa",
+    "/xpcom/base",
+]
+
+if CONFIG["OS_ARCH"] == "WINNT":
+    LOCAL_INCLUDES += [
+        "/xpcom/base",
+    ]
+
+include("/ipc/chromium/chromium-config.mozbuild")
+
+FINAL_LIBRARY = "xul"
+
+if CONFIG["MOZ_WIDGET_TOOLKIT"] == "gtk":
+    CXXFLAGS += CONFIG["MOZ_GTK3_CFLAGS"]
diff --git a/dom/plugins/base/nsIPluginTag.idl b/dom/plugins/base/nsIPluginTag.idl
new file mode 100644
index 0000000000..68f8da1dc8
--- /dev/null
+++ b/dom/plugins/base/nsIPluginTag.idl
@@ -0,0 +1,97 @@
+/* -*- Mode: IDL; tab-width: 2; 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 "nsISupports.idl"
+
+interface nsIURI;
+
+[builtinclass, scriptable, uuid(5daa99d5-265a-4397-b429-c943803e2619)]
+interface nsIPluginTag : nsISupports
+{
+  // enabledState is stored as one of the following as an integer in prefs,
+  // so if new states are added, they must not renumber the existing states.
+  const unsigned long STATE_DISABLED = 0;
+  const unsigned long STATE_CLICKTOPLAY = 1;
+  const unsigned long STATE_ENABLED = 2;
+
+  readonly attribute AUTF8String description;
+  readonly attribute AUTF8String filename;
+  readonly attribute AUTF8String fullpath;
+  readonly attribute AUTF8String version;
+  readonly attribute AUTF8String name;
+
+  // The 'nice' name of this plugin, e.g. 'flash' 'java'
+  readonly attribute AUTF8String niceName;
+
+  /**
+   * true only if this plugin is "hardblocked" and cannot be enabled.
+   */
+  // FIXME-jsplugins QI to fakePluginTag possible
+  // FIXME-jsplugins implement missing + tests (whatever that means)
+  [infallible]
+  readonly attribute boolean blocklisted;
+
+  /**
+   * true if the state is non-default and locked, false otherwise.
+   */
+  [infallible]
+  readonly attribute boolean isEnabledStateLocked;
+
+  // If this plugin is capable of being used (not disabled, blocklisted, etc)
+  [infallible]
+  readonly attribute boolean active;
+
+  // Get a specific nsIBlocklistService::STATE_*
+  [infallible]
+  readonly attribute unsigned long blocklistState;
+
+  [infallible]
+  readonly attribute boolean disabled;
+  [infallible]
+  readonly attribute boolean clicktoplay;
+  [infallible]
+  readonly attribute boolean loaded;
+  // See the STATE_* values above.
+           attribute unsigned long enabledState;
+
+  readonly attribute PRTime lastModifiedTime;
+
+  readonly attribute boolean isFlashPlugin;
+
+  Array<AUTF8String> getMimeTypes();
+  Array<AUTF8String> getMimeDescriptions();
+  Array<AUTF8String> getExtensions();
+
+  /**
+   * An id for this plugin. 0 is a valid id.
+   */
+  readonly attribute unsigned long id;
+};
+
+/**
+ * An interface representing a "fake" plugin: one implemented in JavaScript, not
+ * as a NPAPI plug-in.  See nsIPluginHost.registerFakePlugin and the
+ * documentation for the FakePluginTagInit dictionary.
+ */
+[builtinclass, scriptable, uuid(6d22c968-226d-4156-b230-da6ad6bbf6e8)]
+interface nsIFakePluginTag : nsIPluginTag
+{
+  /**
+   * The URI that should be loaded into the tag (as a frame) to handle the
+   * plugin. Note that the original data/src value for the plugin is not loaded
+   * and will need to be requested by the handler via XHR or similar if desired.
+   */
+  readonly attribute nsIURI handlerURI;
+
+  /**
+   * Optional script to run in a sandbox when instantiating a plugin. If this
+   * value is an empty string then no such script will be run.
+   * The script runs in a sandbox with system principal in the process that
+   * contains the element that instantiates the plugin (ie the EMBED or OBJECT
+   * element). The sandbox global has a 'pluginElement' property that the script
+   * can use to access the element that instantiates the plugin.
+   */
+  readonly attribute AString sandboxScript;
+};
diff --git a/dom/plugins/base/nsPluginHost.cpp b/dom/plugins/base/nsPluginHost.cpp
new file mode 100644
index 0000000000..1c94e60002
--- /dev/null
+++ b/dom/plugins/base/nsPluginHost.cpp
@@ -0,0 +1,223 @@
+/* -*- Mode: C++; tab-width: 2; 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/. */
+
+/* nsPluginHost.cpp - top-level plugin management code */
+
+#include "nsPluginHost.h"
+
+#include "nscore.h"
+
+#include <cstdlib>
+#include <stdio.h>
+#include "nsPluginLogging.h"
+#include "mozilla/Preferences.h"
+#include "mozilla/ProfilerLabels.h"
+#include "nsIBlocklistService.h"
+#include "mozilla/ClearOnShutdown.h"
+#include "nsXULAppAPI.h"
+
+using namespace mozilla;
+
+LazyLogModule nsPluginLogging::gNPNLog(NPN_LOG_NAME);
+LazyLogModule nsPluginLogging::gNPPLog(NPP_LOG_NAME);
+LazyLogModule nsPluginLogging::gPluginLog(PLUGIN_LOG_NAME);
+
+StaticRefPtr<nsPluginHost> nsPluginHost::sInst;
+
+nsPluginHost::nsPluginHost() : mPluginEpoch(0) {
+#ifdef PLUGIN_LOGGING
+  MOZ_LOG(nsPluginLogging::gNPNLog, PLUGIN_LOG_ALWAYS,
+          ("NPN Logging Active!\n"));
+  MOZ_LOG(nsPluginLogging::gPluginLog, PLUGIN_LOG_ALWAYS,
+          ("General Plugin Logging Active! (nsPluginHost::ctor)\n"));
+  MOZ_LOG(nsPluginLogging::gNPPLog, PLUGIN_LOG_ALWAYS,
+          ("NPP Logging Active!\n"));
+
+  PLUGIN_LOG(PLUGIN_LOG_ALWAYS, ("nsPluginHost::ctor\n"));
+  PR_LogFlush();
+#endif
+
+  // Load plugins on creation, as there's a good chance we'll need to send them
+  // to content processes directly after creation.
+  if (XRE_IsParentProcess()) {
+    // Always increment the chrome epoch when we bring up the nsPluginHost in
+    // the parent process.
+    IncrementChromeEpoch();
+  }
+}
+
+nsPluginHost::~nsPluginHost() {
+  PLUGIN_LOG(PLUGIN_LOG_ALWAYS, ("nsPluginHost::dtor\n"));
+}
+
+NS_IMPL_ISUPPORTS(nsPluginHost, nsISupportsWeakReference)
+
+already_AddRefed<nsPluginHost> nsPluginHost::GetInst() {
+  if (!sInst) {
+    sInst = new nsPluginHost();
+    ClearOnShutdown(&sInst);
+  }
+
+  return do_AddRef(sInst);
+}
+
+bool nsPluginHost::HavePluginForType(const nsACString& aMimeType,
+                                     PluginFilter aFilter) {
+  bool checkEnabled = aFilter & eExcludeDisabled;
+  bool allowFake = !(aFilter & eExcludeFake);
+  return FindPluginForType(aMimeType, allowFake, checkEnabled);
+}
+
+nsIInternalPluginTag* nsPluginHost::FindPluginForType(
+    const nsACString& aMimeType, bool aIncludeFake, bool aCheckEnabled) {
+  if (aIncludeFake) {
+    return FindFakePluginForType(aMimeType, aCheckEnabled);
+  }
+
+  return nullptr;
+}
+
+NS_IMETHODIMP
+nsPluginHost::GetPluginTagForType(const nsACString& aMimeType,
+                                  uint32_t aExcludeFlags,
+                                  nsIPluginTag** aResult) {
+  bool includeFake = !(aExcludeFlags & eExcludeFake);
+  bool includeDisabled = !(aExcludeFlags & eExcludeDisabled);
+
+  // First look for an enabled plugin.
+  RefPtr<nsIInternalPluginTag> tag =
+      FindPluginForType(aMimeType, includeFake, true);
+  if (!tag && includeDisabled) {
+    tag = FindPluginForType(aMimeType, includeFake, false);
+  }
+
+  if (tag) {
+    tag.forget(aResult);
+    return NS_OK;
+  }
+
+  return NS_ERROR_NOT_AVAILABLE;
+}
+
+NS_IMETHODIMP
+nsPluginHost::GetPermissionStringForTag(nsIPluginTag* aTag,
+                                        uint32_t aExcludeFlags,
+                                        nsACString& aPermissionString) {
+  NS_ENSURE_TRUE(aTag, NS_ERROR_FAILURE);
+
+  aPermissionString.Truncate();
+  uint32_t blocklistState;
+  nsresult rv = aTag->GetBlocklistState(&blocklistState);
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  aPermissionString.AssignLiteral("plugin:");
+
+  nsCString niceName;
+  rv = aTag->GetNiceName(niceName);
+  NS_ENSURE_SUCCESS(rv, rv);
+  NS_ENSURE_TRUE(!niceName.IsEmpty(), NS_ERROR_FAILURE);
+
+  aPermissionString.Append(niceName);
+
+  return NS_OK;
+}
+
+nsFakePluginTag* nsPluginHost::FindFakePluginForType(
+    const nsACString& aMimeType, bool aCheckEnabled) {
+  int32_t numFakePlugins = mFakePlugins.Length();
+  for (int32_t i = 0; i < numFakePlugins; i++) {
+    nsFakePluginTag* plugin = mFakePlugins[i];
+    bool active;
+    if ((!aCheckEnabled ||
+         (NS_SUCCEEDED(plugin->GetActive(&active)) && active)) &&
+        plugin->HasMimeType(aMimeType)) {
+      return plugin;
+    }
+  }
+
+  return nullptr;
+}
+
+static bool MimeTypeIsAllowedForFakePlugin(const nsString& aMimeType) {
+  static const char* const allowedFakePlugins[] = {
+      // PDF
+      "application/pdf",
+      "application/vnd.adobe.pdf",
+      "application/vnd.adobe.pdfxml",
+      "application/vnd.adobe.x-mars",
+      "application/vnd.adobe.xdp+xml",
+      "application/vnd.adobe.xfdf",
+      "application/vnd.adobe.xfd+xml",
+      "application/vnd.fdf",
+  };
+
+  for (const auto allowed : allowedFakePlugins) {
+    if (aMimeType.EqualsASCII(allowed)) {
+      return true;
+    }
+  }
+  return false;
+}
+
+nsPluginHost::SpecialType nsPluginHost::GetSpecialType(
+    const nsACString& aMIMEType) {
+  if (aMIMEType.LowerCaseEqualsASCII("application/x-test")) {
+    return eSpecialType_Test;
+  }
+
+  if (aMIMEType.LowerCaseEqualsASCII("application/x-shockwave-flash") ||
+      aMIMEType.LowerCaseEqualsASCII("application/futuresplash") ||
+      aMIMEType.LowerCaseEqualsASCII("application/x-shockwave-flash-test")) {
+    return eSpecialType_Flash;
+  }
+
+  return eSpecialType_None;
+}
+
+// Check whether or not a tag is a live, valid tag, and that it's loaded.
+bool nsPluginHost::IsLiveTag(nsIPluginTag* aPluginTag) {
+  nsCOMPtr<nsIInternalPluginTag> internalTag(do_QueryInterface(aPluginTag));
+  uint32_t fakeCount = mFakePlugins.Length();
+  for (uint32_t i = 0; i < fakeCount; i++) {
+    if (mFakePlugins[i] == internalTag) {
+      return true;
+    }
+  }
+  return false;
+}
+
+void nsPluginHost::IncrementChromeEpoch() {
+  MOZ_ASSERT(XRE_IsParentProcess());
+  mPluginEpoch++;
+}
+
+uint32_t nsPluginHost::ChromeEpoch() {
+  MOZ_ASSERT(XRE_IsParentProcess());
+  return mPluginEpoch;
+}
+
+uint32_t nsPluginHost::ChromeEpochForContent() {
+  MOZ_ASSERT(XRE_IsContentProcess());
+  return mPluginEpoch;
+}
+
+void nsPluginHost::SetChromeEpochForContent(uint32_t aEpoch) {
+  MOZ_ASSERT(XRE_IsContentProcess());
+  mPluginEpoch = aEpoch;
+}
+
+/* static */
+bool nsPluginHost::CanUsePluginForMIMEType(const nsACString& aMIMEType) {
+  // We "support" these in the sense that we show a special transparent
+  // fallback element in their place.
+  if (nsPluginHost::GetSpecialType(aMIMEType) ==
+          nsPluginHost::eSpecialType_Flash ||
+      MimeTypeIsAllowedForFakePlugin(NS_ConvertUTF8toUTF16(aMIMEType)) ||
+      aMIMEType.LowerCaseEqualsLiteral("application/x-test")) {
+    return true;
+  }
+
+  return false;
+}
diff --git a/dom/plugins/base/nsPluginHost.h b/dom/plugins/base/nsPluginHost.h
new file mode 100644
index 0000000000..6566e979f3
--- /dev/null
+++ b/dom/plugins/base/nsPluginHost.h
@@ -0,0 +1,111 @@
+/* -*- Mode: C++; tab-width: 2; 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/. */
+
+#ifndef nsPluginHost_h_
+#define nsPluginHost_h_
+
+#include "mozilla/StaticPtr.h"
+
+#include "nsCOMPtr.h"
+#include "prlink.h"
+#include "nsIPluginTag.h"
+#include "nsWeakReference.h"
+#include "nsTArray.h"
+#include "nsPluginTags.h"
+
+class nsIFile;
+
+class nsPluginHost final : public nsSupportsWeakReference {
+  friend class nsFakePluginTag;
+  virtual ~nsPluginHost();
+
+ public:
+  nsPluginHost();
+
+  static already_AddRefed<nsPluginHost> GetInst();
+
+  NS_DECL_ISUPPORTS
+
+  // Acts like a bitfield
+  enum PluginFilter { eExcludeNone, eExcludeDisabled, eExcludeFake };
+
+  NS_IMETHOD GetPluginTagForType(const nsACString& aMimeType,
+                                 uint32_t aExcludeFlags,
+                                 nsIPluginTag** aResult);
+  NS_IMETHOD GetPermissionStringForTag(nsIPluginTag* aTag,
+                                       uint32_t aExcludeFlags,
+                                       nsACString& aPermissionString);
+
+  // FIXME-jsplugins comment about fake
+  bool HavePluginForType(const nsACString& aMimeType,
+                         PluginFilter aFilter = eExcludeDisabled);
+
+  void GetPlugins(nsTArray<nsCOMPtr<nsIInternalPluginTag>>& aPluginArray,
+                  bool aIncludeDisabled = false);
+
+  /**
+   * Returns true if a plugin can be used to load the requested MIME type. Used
+   * for short circuiting before sending things to plugin code.
+   */
+  static bool CanUsePluginForMIMEType(const nsACString& aMIMEType);
+
+  // checks whether aType is a type we recognize for potential special handling
+  enum SpecialType {
+    eSpecialType_None,
+    // Needed to whitelist for async init support
+    eSpecialType_Test,
+    // Informs some decisions about OOP and quirks
+    eSpecialType_Flash
+  };
+  static SpecialType GetSpecialType(const nsACString& aMIMEType);
+
+ private:
+  // Find a plugin for the given type.  If aIncludeFake is true a fake plugin
+  // will be preferred if one exists; otherwise a fake plugin will never be
+  // returned.  If aCheckEnabled is false, disabled plugins can be returned.
+  nsIInternalPluginTag* FindPluginForType(const nsACString& aMimeType,
+                                          bool aIncludeFake,
+                                          bool aCheckEnabled);
+
+  // Find specifically a fake plugin for the given type.  If aCheckEnabled is
+  // false, disabled plugins can be returned.
+  nsFakePluginTag* FindFakePluginForType(const nsACString& aMimeType,
+                                         bool aCheckEnabled);
+
+  // Find specifically a fake plugin for the given extension.  If aCheckEnabled
+  // is false, disabled plugins can be returned.  aMimeType will be filled in
+  // with the MIME type the plugin is registered for.
+  nsFakePluginTag* FindFakePluginForExtension(const nsACString& aExtension,
+                                              /* out */ nsACString& aMimeType,
+                                              bool aCheckEnabled);
+
+  // Checks to see if a tag object is in our list of live tags.
+  bool IsLiveTag(nsIPluginTag* tag);
+
+  // To be used by the chrome process whenever the set of plugins changes.
+  void IncrementChromeEpoch();
+
+  // To be used by the chrome process; returns the current epoch.
+  uint32_t ChromeEpoch();
+
+  // To be used by the content process to get/set the last observed epoch value
+  // from the chrome process.
+  uint32_t ChromeEpochForContent();
+  void SetChromeEpochForContent(uint32_t aEpoch);
+
+  nsTArray<RefPtr<nsFakePluginTag>> mFakePlugins;
+
+  // This epoch increases each time we load the list of plugins from disk.
+  // In the chrome process, this stores the actual epoch.
+  // In the content process, this stores the last epoch value observed
+  // when reading plugins from chrome.
+  uint32_t mPluginEpoch;
+
+  // We need to hold a global ptr to ourselves because we register for
+  // two different CIDs for some reason...
+  static mozilla::StaticRefPtr<nsPluginHost> sInst;
+};
+
+#endif  // nsPluginHost_h_
diff --git a/dom/plugins/base/nsPluginLogging.h b/dom/plugins/base/nsPluginLogging.h
new file mode 100644
index 0000000000..029a073308
--- /dev/null
+++ b/dom/plugins/base/nsPluginLogging.h
@@ -0,0 +1,54 @@
+/* -*- 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/. */
+
+/* Plugin Module Logging usage instructions and includes */
+////////////////////////////////////////////////////////////////////////////////
+#ifndef nsPluginLogging_h__
+#define nsPluginLogging_h__
+
+#include "mozilla/Logging.h"
+
+////////////////////////////////////////////////////////////////////////////////
+// Basic Plugin Logging Usage Instructions
+//
+// 1. Set this environment variable: MOZ_LOG=<name>:<level>
+
+// Choose the <name> and <level> from this list (no quotes):
+
+// Log Names            <name>
+#define NPN_LOG_NAME "PluginNPN"
+#define NPP_LOG_NAME "PluginNPP"
+#define PLUGIN_LOG_NAME "Plugin"
+
+// Levels                <level>
+#define PLUGIN_LOG_ALWAYS mozilla::LogLevel::Error
+#define PLUGIN_LOG_BASIC mozilla::LogLevel::Info
+#define PLUGIN_LOG_NORMAL mozilla::LogLevel::Debug
+#define PLUGIN_LOG_NOISY mozilla::LogLevel::Verbose
+
+// 2. You can combine logs and levels by separating them with a comma:
+//    My favorite Win32 Example: SET MOZ_LOG=Plugin:5,PluginNPP:5,PluginNPN:5
+
+// 3. Instead of output going to the console, you can log to a file.
+//    Additionally, set the MOZ_LOG_FILE environment variable to point to the
+//    full path of a file.
+//    My favorite Win32 Example: SET MOZ_LOG_FILE=c:\temp\pluginLog.txt
+
+// 4. For complete information see the Gecko Developer guide:
+// https://firefox-source-docs.mozilla.org/xpcom/logging.html
+
+class nsPluginLogging {
+ public:
+  static mozilla::LazyLogModule gNPNLog;     // 4.x NP API, calls into navigator
+  static mozilla::LazyLogModule gNPPLog;     // 4.x NP API, calls into plugin
+  static mozilla::LazyLogModule gPluginLog;  // general plugin log
+};
+
+// Quick-use macros
+#define NPN_PLUGIN_LOG(a, b) MOZ_LOG(nsPluginLogging::gNPNLog, a, b)
+#define NPP_PLUGIN_LOG(a, b) MOZ_LOG(nsPluginLogging::gNPPLog, a, b)
+#define PLUGIN_LOG(a, b) MOZ_LOG(nsPluginLogging::gPluginLog, a, b)
+
+#endif  // nsPluginLogging_h__
diff --git a/dom/plugins/base/nsPluginTags.cpp b/dom/plugins/base/nsPluginTags.cpp
new file mode 100644
index 0000000000..c1a660a3db
--- /dev/null
+++ b/dom/plugins/base/nsPluginTags.cpp
@@ -0,0 +1,393 @@
+/* -*- Mode: C++; tab-width: 2; 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 "nsPluginTags.h"
+
+#include "prlink.h"
+#include "plstr.h"
+#include "prenv.h"
+#include "nsPluginHost.h"
+#include "nsIBlocklistService.h"
+#include "nsPluginLogging.h"
+#include "nsCharSeparatedTokenizer.h"
+#include "mozilla/Preferences.h"
+#include "mozilla/Unused.h"
+#include "nsNetUtil.h"
+#include <cctype>
+#include "mozilla/Encoding.h"
+#include "mozilla/dom/FakePluginTagInitBinding.h"
+#include "mozilla/StaticPrefs_plugin.h"
+
+using mozilla::dom::FakePluginTagInit;
+using namespace mozilla;
+
+// check comma delimited extensions
+static bool ExtensionInList(const nsCString& aExtensionList,
+                            const nsACString& aExtension) {
+  for (const nsACString& extension :
+       nsCCharSeparatedTokenizer(aExtensionList, ',').ToRange()) {
+    if (extension.Equals(aExtension, nsCaseInsensitiveCStringComparator)) {
+      return true;
+    }
+  }
+  return false;
+}
+
+// Search for an extension in an extensions array, and return its
+// matching mime type
+static bool SearchExtensions(const nsTArray<nsCString>& aExtensions,
+                             const nsTArray<nsCString>& aMimeTypes,
+                             const nsACString& aFindExtension,
+                             nsACString& aMatchingType) {
+  uint32_t mimes = aMimeTypes.Length();
+  MOZ_ASSERT(mimes == aExtensions.Length(),
+             "These arrays should have matching elements");
+
+  aMatchingType.Truncate();
+
+  for (uint32_t i = 0; i < mimes; i++) {
+    if (ExtensionInList(aExtensions[i], aFindExtension)) {
+      aMatchingType = aMimeTypes[i];
+      return true;
+    }
+  }
+
+  return false;
+}
+
+static nsCString MakeNiceFileName(const nsCString& aFileName) {
+  nsCString niceName = aFileName;
+  int32_t niceNameLength = aFileName.RFind(".");
+  NS_ASSERTION(niceNameLength != kNotFound, "aFileName doesn't have a '.'?");
+  while (niceNameLength > 0) {
+    char chr = aFileName[niceNameLength - 1];
+    if (!std::isalpha(chr))
+      niceNameLength--;
+    else
+      break;
+  }
+
+  // If it turns out that niceNameLength <= 0, we'll fall back and use the
+  // entire aFileName (which we've already taken care of, a few lines back).
+  if (niceNameLength > 0) {
+    niceName.Truncate(niceNameLength);
+  }
+
+  ToLowerCase(niceName);
+  return niceName;
+}
+
+static nsCString MakePrefNameForPlugin(const char* const subname,
+                                       nsIInternalPluginTag* aTag) {
+  nsCString pref;
+  nsAutoCString pluginName(aTag->GetNiceFileName());
+
+  if (pluginName.IsEmpty()) {
+    // Use filename if nice name fails
+    pluginName = aTag->FileName();
+    if (pluginName.IsEmpty()) {
+      MOZ_ASSERT_UNREACHABLE("Plugin with no filename or nice name in list");
+      pluginName.AssignLiteral("unknown-plugin-name");
+    }
+  }
+
+  pref.AssignLiteral("plugin.");
+  pref.Append(subname);
+  pref.Append('.');
+  pref.Append(pluginName);
+
+  return pref;
+}
+
+static nsCString GetStatePrefNameForPlugin(nsIInternalPluginTag* aTag) {
+  return MakePrefNameForPlugin("state", aTag);
+}
+
+static nsresult IsEnabledStateLockedForPlugin(nsIInternalPluginTag* aTag,
+                                              bool* aIsEnabledStateLocked) {
+  *aIsEnabledStateLocked = false;
+  nsCOMPtr<nsIPrefBranch> prefs(do_GetService(NS_PREFSERVICE_CONTRACTID));
+
+  if (NS_WARN_IF(!prefs)) {
+    return NS_ERROR_FAILURE;
+  }
+
+  Unused << prefs->PrefIsLocked(GetStatePrefNameForPlugin(aTag).get(),
+                                aIsEnabledStateLocked);
+
+  return NS_OK;
+}
+
+/* nsIInternalPluginTag */
+
+uint32_t nsIInternalPluginTag::sNextId;
+
+nsIInternalPluginTag::nsIInternalPluginTag() = default;
+
+nsIInternalPluginTag::nsIInternalPluginTag(const char* aName,
+                                           const char* aDescription,
+                                           const char* aFileName,
+                                           const char* aVersion)
+    : mName(aName),
+      mDescription(aDescription),
+      mFileName(aFileName),
+      mVersion(aVersion) {}
+
+nsIInternalPluginTag::nsIInternalPluginTag(
+    const char* aName, const char* aDescription, const char* aFileName,
+    const char* aVersion, const nsTArray<nsCString>& aMimeTypes,
+    const nsTArray<nsCString>& aMimeDescriptions,
+    const nsTArray<nsCString>& aExtensions)
+    : mName(aName),
+      mDescription(aDescription),
+      mFileName(aFileName),
+      mVersion(aVersion),
+      mMimeTypes(aMimeTypes.Clone()),
+      mMimeDescriptions(aMimeDescriptions.Clone()),
+      mExtensions(aExtensions.Clone()) {}
+
+nsIInternalPluginTag::~nsIInternalPluginTag() = default;
+
+bool nsIInternalPluginTag::HasExtension(const nsACString& aExtension,
+                                        nsACString& aMatchingType) const {
+  return SearchExtensions(mExtensions, mMimeTypes, aExtension, aMatchingType);
+}
+
+bool nsIInternalPluginTag::HasMimeType(const nsACString& aMimeType) const {
+  return mMimeTypes.Contains(aMimeType,
+                             nsCaseInsensitiveCStringArrayComparator());
+}
+
+/* nsFakePluginTag */
+
+nsFakePluginTag::nsFakePluginTag()
+    : mId(sNextId++), mState(ePluginState_Disabled) {}
+
+nsFakePluginTag::nsFakePluginTag(uint32_t aId,
+                                 already_AddRefed<nsIURI>&& aHandlerURI,
+                                 const char* aName, const char* aDescription,
+                                 const nsTArray<nsCString>& aMimeTypes,
+                                 const nsTArray<nsCString>& aMimeDescriptions,
+                                 const nsTArray<nsCString>& aExtensions,
+                                 const nsCString& aNiceName,
+                                 const nsString& aSandboxScript)
+    : nsIInternalPluginTag(aName, aDescription, nullptr, nullptr, aMimeTypes,
+                           aMimeDescriptions, aExtensions),
+      mId(aId),
+      mHandlerURI(aHandlerURI),
+      mNiceName(aNiceName),
+      mSandboxScript(aSandboxScript),
+      mState(ePluginState_Enabled) {}
+
+nsFakePluginTag::~nsFakePluginTag() = default;
+
+NS_IMPL_ADDREF(nsFakePluginTag)
+NS_IMPL_RELEASE(nsFakePluginTag)
+NS_INTERFACE_TABLE_HEAD(nsFakePluginTag)
+  NS_INTERFACE_TABLE_BEGIN
+    NS_INTERFACE_TABLE_ENTRY_AMBIGUOUS(nsFakePluginTag, nsIPluginTag,
+                                       nsIInternalPluginTag)
+    NS_INTERFACE_TABLE_ENTRY(nsFakePluginTag, nsIInternalPluginTag)
+    NS_INTERFACE_TABLE_ENTRY_AMBIGUOUS(nsFakePluginTag, nsISupports,
+                                       nsIInternalPluginTag)
+    NS_INTERFACE_TABLE_ENTRY(nsFakePluginTag, nsIFakePluginTag)
+  NS_INTERFACE_TABLE_END
+NS_INTERFACE_TABLE_TAIL
+
+/* static */
+nsresult nsFakePluginTag::Create(const FakePluginTagInit& aInitDictionary,
+                                 nsFakePluginTag** aPluginTag) {
+  NS_ENSURE_TRUE(sNextId <= PR_INT32_MAX, NS_ERROR_OUT_OF_MEMORY);
+  NS_ENSURE_TRUE(!aInitDictionary.mMimeEntries.IsEmpty(), NS_ERROR_INVALID_ARG);
+
+  RefPtr<nsFakePluginTag> tag = new nsFakePluginTag();
+  nsresult rv =
+      NS_NewURI(getter_AddRefs(tag->mHandlerURI), aInitDictionary.mHandlerURI);
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  CopyUTF16toUTF8(aInitDictionary.mNiceName, tag->mNiceName);
+  CopyUTF16toUTF8(aInitDictionary.mFullPath, tag->mFullPath);
+  CopyUTF16toUTF8(aInitDictionary.mName, tag->mName);
+  CopyUTF16toUTF8(aInitDictionary.mDescription, tag->mDescription);
+  CopyUTF16toUTF8(aInitDictionary.mFileName, tag->mFileName);
+  CopyUTF16toUTF8(aInitDictionary.mVersion, tag->mVersion);
+  tag->mSandboxScript = aInitDictionary.mSandboxScript;
+
+  for (const mozilla::dom::FakePluginMimeEntry& mimeEntry :
+       aInitDictionary.mMimeEntries) {
+    CopyUTF16toUTF8(mimeEntry.mType, *tag->mMimeTypes.AppendElement());
+    CopyUTF16toUTF8(mimeEntry.mDescription,
+                    *tag->mMimeDescriptions.AppendElement());
+    CopyUTF16toUTF8(mimeEntry.mExtension, *tag->mExtensions.AppendElement());
+  }
+
+  tag.forget(aPluginTag);
+  return NS_OK;
+}
+
+bool nsFakePluginTag::HandlerURIMatches(nsIURI* aURI) {
+  bool equals = false;
+  return NS_SUCCEEDED(mHandlerURI->Equals(aURI, &equals)) && equals;
+}
+
+NS_IMETHODIMP
+nsFakePluginTag::GetHandlerURI(nsIURI** aResult) {
+  NS_IF_ADDREF(*aResult = mHandlerURI);
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsFakePluginTag::GetSandboxScript(nsAString& aSandboxScript) {
+  aSandboxScript = mSandboxScript;
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsFakePluginTag::GetDescription(/* utf-8 */ nsACString& aResult) {
+  aResult = mDescription;
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsFakePluginTag::GetIsFlashPlugin(bool* aIsFlash) {
+  *aIsFlash = false;
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsFakePluginTag::GetFilename(/* utf-8 */ nsACString& aResult) {
+  aResult = mFileName;
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsFakePluginTag::GetFullpath(/* utf-8 */ nsACString& aResult) {
+  aResult = mFullPath;
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsFakePluginTag::GetVersion(/* utf-8 */ nsACString& aResult) {
+  aResult = mVersion;
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsFakePluginTag::GetName(/* utf-8 */ nsACString& aResult) {
+  aResult = mName;
+  return NS_OK;
+}
+
+const nsCString& nsFakePluginTag::GetNiceFileName() {
+  // We don't try to mimic the special-cased flash/java names if the fake plugin
+  // claims one of their MIME types, but do allow directly setting niceName if
+  // emulating those is desired.
+  if (mNiceName.IsEmpty() && !mFileName.IsEmpty()) {
+    mNiceName = MakeNiceFileName(mFileName);
+  }
+
+  return mNiceName;
+}
+
+NS_IMETHODIMP
+nsFakePluginTag::GetNiceName(/* utf-8 */ nsACString& aResult) {
+  aResult = GetNiceFileName();
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsFakePluginTag::GetBlocklistState(uint32_t* aResult) {
+  // Fake tags don't currently support blocklisting
+  *aResult = nsIBlocklistService::STATE_NOT_BLOCKED;
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsFakePluginTag::GetBlocklisted(bool* aBlocklisted) {
+  // Fake tags can't be blocklisted
+  *aBlocklisted = false;
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsFakePluginTag::GetIsEnabledStateLocked(bool* aIsEnabledStateLocked) {
+  return IsEnabledStateLockedForPlugin(this, aIsEnabledStateLocked);
+}
+
+bool nsFakePluginTag::IsEnabled() {
+  return mState == ePluginState_Enabled || mState == ePluginState_Clicktoplay;
+}
+
+NS_IMETHODIMP
+nsFakePluginTag::GetDisabled(bool* aDisabled) {
+  *aDisabled = !IsEnabled();
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsFakePluginTag::GetClicktoplay(bool* aClicktoplay) {
+  *aClicktoplay = (mState == ePluginState_Clicktoplay);
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsFakePluginTag::GetEnabledState(uint32_t* aEnabledState) {
+  *aEnabledState = (uint32_t)mState;
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsFakePluginTag::SetEnabledState(uint32_t aEnabledState) {
+  // There are static asserts above enforcing that this enum matches
+  mState = (PluginState)aEnabledState;
+  // FIXME-jsplugins update
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsFakePluginTag::GetMimeTypes(nsTArray<nsCString>& aResults) {
+  aResults = mMimeTypes.Clone();
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsFakePluginTag::GetMimeDescriptions(nsTArray<nsCString>& aResults) {
+  aResults = mMimeDescriptions.Clone();
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsFakePluginTag::GetExtensions(nsTArray<nsCString>& aResults) {
+  aResults = mExtensions.Clone();
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsFakePluginTag::GetActive(bool* aResult) {
+  // Fake plugins can't be blocklisted, so this is just !Disabled
+  *aResult = IsEnabled();
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsFakePluginTag::GetLastModifiedTime(PRTime* aLastModifiedTime) {
+  // FIXME-jsplugins What should this return, if anything?
+  MOZ_ASSERT(aLastModifiedTime);
+  *aLastModifiedTime = 0;
+  return NS_OK;
+}
+
+// We don't load fake plugins out of a library, so they should always be there.
+NS_IMETHODIMP
+nsFakePluginTag::GetLoaded(bool* ret) {
+  *ret = true;
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsFakePluginTag::GetId(uint32_t* aId) {
+  *aId = mId;
+  return NS_OK;
+}
diff --git a/dom/plugins/base/nsPluginTags.h b/dom/plugins/base/nsPluginTags.h
new file mode 100644
index 0000000000..2219112d26
--- /dev/null
+++ b/dom/plugins/base/nsPluginTags.h
@@ -0,0 +1,149 @@
+/* -*- Mode: C++; tab-width: 2; 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/. */
+
+#ifndef nsPluginTags_h_
+#define nsPluginTags_h_
+
+#include "mozilla/Attributes.h"
+#include "nscore.h"
+#include "nsCOMPtr.h"
+#include "nsCOMArray.h"
+#include "nsIPluginTag.h"
+#include "nsITimer.h"
+#include "nsString.h"
+
+class nsIURI;
+
+namespace mozilla::dom {
+struct FakePluginTagInit;
+}  // namespace mozilla::dom
+
+// An interface representing plugin tags internally.
+#define NS_IINTERNALPLUGINTAG_IID                    \
+  {                                                  \
+    0xe8fdd227, 0x27da, 0x46ee, {                    \
+      0xbe, 0xf3, 0x1a, 0xef, 0x5a, 0x8f, 0xc5, 0xb4 \
+    }                                                \
+  }
+
+class nsIInternalPluginTag : public nsIPluginTag {
+ public:
+  NS_DECLARE_STATIC_IID_ACCESSOR(NS_IINTERNALPLUGINTAG_IID)
+
+  nsIInternalPluginTag();
+  nsIInternalPluginTag(const char* aName, const char* aDescription,
+                       const char* aFileName, const char* aVersion);
+  nsIInternalPluginTag(const char* aName, const char* aDescription,
+                       const char* aFileName, const char* aVersion,
+                       const nsTArray<nsCString>& aMimeTypes,
+                       const nsTArray<nsCString>& aMimeDescriptions,
+                       const nsTArray<nsCString>& aExtensions);
+
+  virtual bool IsEnabled() = 0;
+  virtual const nsCString& GetNiceFileName() = 0;
+
+  const nsCString& Name() const { return mName; }
+  const nsCString& Description() const { return mDescription; }
+
+  const nsTArray<nsCString>& MimeTypes() const { return mMimeTypes; }
+
+  const nsTArray<nsCString>& MimeDescriptions() const {
+    return mMimeDescriptions;
+  }
+
+  const nsTArray<nsCString>& Extensions() const { return mExtensions; }
+
+  const nsCString& FileName() const { return mFileName; }
+
+  const nsCString& Version() const { return mVersion; }
+
+  // Returns true if this plugin claims it supports this MIME type.  The
+  // comparison is done ASCII-case-insensitively.
+  bool HasMimeType(const nsACString& aMimeType) const;
+
+  // Returns true if this plugin claims it supports the given extension.  In
+  // that case, aMatchingType is set to the MIME type the plugin claims
+  // corresponds to this extension.  The match on aExtension is done
+  // ASCII-case-insensitively.
+  bool HasExtension(const nsACString& aExtension,
+                    /* out */ nsACString& aMatchingType) const;
+
+  // These must match the STATE_* values in nsIPluginTag.idl
+  enum PluginState {
+    ePluginState_Disabled = 0,
+    ePluginState_Clicktoplay = 1,
+    ePluginState_Enabled = 2,
+    ePluginState_MaxValue = 3,
+  };
+
+ protected:
+  ~nsIInternalPluginTag();
+
+  nsCString mName;                        // UTF-8
+  nsCString mDescription;                 // UTF-8
+  nsCString mFileName;                    // UTF-8
+  nsCString mVersion;                     // UTF-8
+  nsTArray<nsCString> mMimeTypes;         // UTF-8
+  nsTArray<nsCString> mMimeDescriptions;  // UTF-8
+  nsTArray<nsCString> mExtensions;        // UTF-8
+
+  static uint32_t sNextId;
+};
+NS_DEFINE_STATIC_IID_ACCESSOR(nsIInternalPluginTag, NS_IINTERNALPLUGINTAG_IID)
+
+// A class representing "fake" plugin tags for Javascript-based plugins.
+// There are currently no other types of supported plugins.
+class nsFakePluginTag : public nsIInternalPluginTag, public nsIFakePluginTag {
+ public:
+  NS_DECL_ISUPPORTS
+  NS_DECL_NSIPLUGINTAG
+  NS_DECL_NSIFAKEPLUGINTAG
+
+  static nsresult Create(const mozilla::dom::FakePluginTagInit& aInitDictionary,
+                         nsFakePluginTag** aPluginTag);
+  nsFakePluginTag(uint32_t aId, already_AddRefed<nsIURI>&& aHandlerURI,
+                  const char* aName, const char* aDescription,
+                  const nsTArray<nsCString>& aMimeTypes,
+                  const nsTArray<nsCString>& aMimeDescriptions,
+                  const nsTArray<nsCString>& aExtensions,
+                  const nsCString& aNiceName, const nsString& aSandboxScript);
+
+  bool IsEnabled() override;
+  const nsCString& GetNiceFileName() override;
+
+  bool HandlerURIMatches(nsIURI* aURI);
+
+  nsIURI* HandlerURI() const { return mHandlerURI; }
+
+  uint32_t Id() const { return mId; }
+
+  const nsString& SandboxScript() const { return mSandboxScript; }
+
+  static const int32_t NOT_JSPLUGIN = -1;
+
+ private:
+  nsFakePluginTag();
+  virtual ~nsFakePluginTag();
+
+  // A unique id for this JS-implemented plugin. Registering a plugin through
+  // nsPluginHost::RegisterFakePlugin assigns a new id. The id is transferred
+  // through IPC when getting the list of JS-implemented plugins from child
+  // processes, so it should be consistent across processes.
+  // 0 is a valid id.
+  uint32_t mId;
+
+  // The URI of the handler for our fake plugin.
+  // FIXME-jsplugins do we need to sanity check these?
+  nsCOMPtr<nsIURI> mHandlerURI;
+
+  nsCString mFullPath;
+  nsCString mNiceName;
+
+  nsString mSandboxScript;
+
+  PluginState mState;
+};
+
+#endif  // nsPluginTags_h_