gecko-dev/startupcache/StartupCacheUtils.cpp

/* 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 "nsCOMPtr.h"
#include "nsIInputStream.h"
#include "nsNetUtil.h"
#include "nsIFileURL.h"
#include "nsIJARURI.h"
#include "nsIResProtocolHandler.h"
#include "nsIChromeRegistry.h"
#include "nsStringStream.h"
#include "StartupCacheUtils.h"
#include "mozilla/scache/StartupCache.h"
#include "mozilla/Omnijar.h"

namespace mozilla {
namespace scache {

nsresult NewObjectInputStreamFromBuffer(const char* buffer, uint32_t len,
                                        nsIObjectInputStream** stream) {
  nsCOMPtr<nsIInputStream> stringStream;
  nsresult rv = NS_NewByteInputStream(getter_AddRefs(stringStream),
                                      Span(buffer, len), NS_ASSIGNMENT_DEPEND);
  MOZ_ALWAYS_SUCCEEDS(rv);

  nsCOMPtr<nsIObjectInputStream> objectInput =
      NS_NewObjectInputStream(stringStream);

  objectInput.forget(stream);
  return NS_OK;
}

nsresult NewObjectOutputWrappedStorageStream(
    nsIObjectOutputStream** wrapperStream, nsIStorageStream** stream,
    bool wantDebugStream) {
  nsCOMPtr<nsIStorageStream> storageStream;

  nsresult rv =
      NS_NewStorageStream(256, UINT32_MAX, getter_AddRefs(storageStream));
  NS_ENSURE_SUCCESS(rv, rv);

  nsCOMPtr<nsIOutputStream> outputStream = do_QueryInterface(storageStream);

  nsCOMPtr<nsIObjectOutputStream> objectOutput =
      NS_NewObjectOutputStream(outputStream);

#ifdef DEBUG
  if (wantDebugStream) {
    // Wrap in debug stream to detect unsupported writes of
    // multiply-referenced non-singleton objects
    StartupCache* sc = StartupCache::GetSingleton();
    NS_ENSURE_TRUE(sc, NS_ERROR_UNEXPECTED);
    nsCOMPtr<nsIObjectOutputStream> debugStream;
    sc->GetDebugObjectOutputStream(objectOutput, getter_AddRefs(debugStream));
    debugStream.forget(wrapperStream);
  } else {
    objectOutput.forget(wrapperStream);
  }
#else
  objectOutput.forget(wrapperStream);
#endif

  storageStream.forget(stream);
  return NS_OK;
}

nsresult NewBufferFromStorageStream(nsIStorageStream* storageStream,
                                    UniquePtr<char[]>* buffer, uint32_t* len) {
  nsresult rv;
  nsCOMPtr<nsIInputStream> inputStream;
  rv = storageStream->NewInputStream(0, getter_AddRefs(inputStream));
  NS_ENSURE_SUCCESS(rv, rv);

  uint64_t avail64;
  rv = inputStream->Available(&avail64);
  NS_ENSURE_SUCCESS(rv, rv);
  NS_ENSURE_TRUE(avail64 <= UINT32_MAX, NS_ERROR_FILE_TOO_BIG);

  uint32_t avail = (uint32_t)avail64;
  auto temp = MakeUnique<char[]>(avail);
  uint32_t read;
  rv = inputStream->Read(temp.get(), avail, &read);
  if (NS_SUCCEEDED(rv) && avail != read) rv = NS_ERROR_UNEXPECTED;

  if (NS_FAILED(rv)) {
    return rv;
  }

  *len = avail;
  *buffer = std::move(temp);
  return NS_OK;
}

static const char baseName[2][5] = {"gre/", "app/"};

static inline bool canonicalizeBase(nsAutoCString& spec, nsACString& out) {
  nsAutoCString greBase, appBase;
  nsresult rv = mozilla::Omnijar::GetURIString(mozilla::Omnijar::GRE, greBase);
  if (NS_FAILED(rv) || !greBase.Length()) return false;

  rv = mozilla::Omnijar::GetURIString(mozilla::Omnijar::APP, appBase);
  if (NS_FAILED(rv)) return false;

  bool underGre = !greBase.Compare(spec.get(), false, greBase.Length());
  bool underApp =
      appBase.Length() && !appBase.Compare(spec.get(), false, appBase.Length());

  if (!underGre && !underApp) return false;

  /**
   * At this point, if both underGre and underApp are true, it can be one
   * of the two following cases:
   * - the GRE directory points to a subdirectory of the APP directory,
   *   meaning spec points under GRE.
   * - the APP directory points to a subdirectory of the GRE directory,
   *   meaning spec points under APP.
   * Checking the GRE and APP path length is enough to know in which case
   * we are.
   */
  if (underGre && underApp && greBase.Length() < appBase.Length())
    underGre = false;

  out.AppendLiteral("/resource/");
  out.Append(
      baseName[underGre ? mozilla::Omnijar::GRE : mozilla::Omnijar::APP]);
  out.Append(Substring(spec, underGre ? greBase.Length() : appBase.Length()));
  return true;
}

/**
 * ResolveURI transforms a chrome: or resource: URI into the URI for its
 * underlying resource, or returns any other URI unchanged.
 */
nsresult ResolveURI(nsIURI* in, nsIURI** out) {
  nsresult rv;

  // Resolve resource:// URIs. At the end of this if/else block, we
  // have both spec and uri variables identifying the same URI.
  if (in->SchemeIs("resource")) {
    nsCOMPtr<nsIIOService> ioService = do_GetIOService(&rv);
    NS_ENSURE_SUCCESS(rv, rv);

    nsCOMPtr<nsIProtocolHandler> ph;
    rv = ioService->GetProtocolHandler("resource", getter_AddRefs(ph));
    NS_ENSURE_SUCCESS(rv, rv);

    nsCOMPtr<nsIResProtocolHandler> irph(do_QueryInterface(ph, &rv));
    NS_ENSURE_SUCCESS(rv, rv);

    nsAutoCString spec;
    rv = irph->ResolveURI(in, spec);
    NS_ENSURE_SUCCESS(rv, rv);

    return ioService->NewURI(spec, nullptr, nullptr, out);
  }
  if (in->SchemeIs("chrome")) {
    nsCOMPtr<nsIChromeRegistry> chromeReg =
        mozilla::services::GetChromeRegistry();
    if (!chromeReg) return NS_ERROR_UNEXPECTED;

    return chromeReg->ConvertChromeURL(in, out);
  }

  *out = do_AddRef(in).take();
  return NS_OK;
}

/**
 * PathifyURI transforms uris into useful zip paths
 * to make it easier to manipulate startup cache entries
 * using standard zip tools.
 * Transformations applied:
 *  * resource:// URIs are resolved to their corresponding file/jar URI to
 *    canonicalize resources URIs other than gre and app.
 *  * Paths under GRE or APP directory have their base path replaced with
 *    resource/gre or resource/app to avoid depending on install location.
 *  * jar:file:///path/to/file.jar!/sub/path urls are replaced with
 *    /path/to/file.jar/sub/path
 *
 *  The result is appended to the string passed in. Adding a prefix before
 *  calling is recommended to avoid colliding with other cache users.
 *
 * For example, in the js loader (string is prefixed with jsloader by caller):
 *  resource://gre/modules/XPCOMUtils.jsm or
 *  file://$GRE_DIR/modules/XPCOMUtils.jsm or
 *  jar:file://$GRE_DIR/omni.jar!/modules/XPCOMUtils.jsm becomes
 *     jsloader/resource/gre/modules/XPCOMUtils.jsm
 *  file://$PROFILE_DIR/extensions/{uuid}/components/component.js becomes
 *     jsloader/$PROFILE_DIR/extensions/%7Buuid%7D/components/component.js
 *  jar:file://$PROFILE_DIR/extensions/some.xpi!/components/component.js becomes
 *     jsloader/$PROFILE_DIR/extensions/some.xpi/components/component.js
 */
nsresult PathifyURI(nsIURI* in, nsACString& out) {
  nsCOMPtr<nsIURI> uri;
  nsresult rv = ResolveURI(in, getter_AddRefs(uri));
  NS_ENSURE_SUCCESS(rv, rv);

  nsAutoCString spec;
  rv = uri->GetSpec(spec);
  NS_ENSURE_SUCCESS(rv, rv);

  if (!canonicalizeBase(spec, out)) {
    if (uri->SchemeIs("file")) {
      nsCOMPtr<nsIFileURL> baseFileURL;
      baseFileURL = do_QueryInterface(uri, &rv);
      NS_ENSURE_SUCCESS(rv, rv);

      nsAutoCString path;
      rv = baseFileURL->GetPathQueryRef(path);
      NS_ENSURE_SUCCESS(rv, rv);

      out.Append(path);
    } else if (uri->SchemeIs("jar")) {
      nsCOMPtr<nsIJARURI> jarURI = do_QueryInterface(uri, &rv);
      NS_ENSURE_SUCCESS(rv, rv);

      nsCOMPtr<nsIURI> jarFileURI;
      rv = jarURI->GetJARFile(getter_AddRefs(jarFileURI));
      NS_ENSURE_SUCCESS(rv, rv);

      rv = PathifyURI(jarFileURI, out);
      NS_ENSURE_SUCCESS(rv, rv);

      nsAutoCString path;
      rv = jarURI->GetJAREntry(path);
      NS_ENSURE_SUCCESS(rv, rv);
      out.Append('/');
      out.Append(path);
    } else {  // Very unlikely
      rv = uri->GetSpec(spec);
      NS_ENSURE_SUCCESS(rv, rv);

      out.Append('/');
      out.Append(spec);
    }
  }
  return NS_OK;
}

}  // namespace scache
}  // namespace mozilla