/* -*- 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 "nsHyphenator.h"

#include "mozilla/dom/ContentChild.h"
#include "mozilla/Omnijar.h"
#include "mozilla/ipc/SharedMemoryHandle.h"
#include "mozilla/ipc/SharedMemoryMapping.h"
#include "nsContentUtils.h"
#include "nsEscape.h"
#include "nsIChannel.h"
#include "nsIFile.h"
#include "nsIFileURL.h"
#include "nsIInputStream.h"
#include "nsIJARURI.h"
#include "nsIURI.h"
#include "nsNetUtil.h"
#include "nsUnicodeProperties.h"
#include "nsUTF8Utils.h"
#include "nsZipArchive.h"

#include "mapped_hyph.h"

using namespace mozilla;

namespace std {
void default_delete<const HyphDic>::operator()(const HyphDic* aHyph) const {
  mapped_hyph_free_dictionary(const_cast<HyphDic*>(aHyph));
}

void default_delete<const CompiledData>::operator()(
    const CompiledData* aData) const {
  mapped_hyph_free_compiled_data(const_cast<CompiledData*>(aData));
}
}  // namespace std

static const uint8_t* GetItemPtrFromJarURI(nsIJARURI* aJAR, uint32_t* aLength) {
  // Try to get the jarfile's nsZipArchive, find the relevant item, and return
  // a pointer to its data provided it is stored uncompressed.
  nsCOMPtr<nsIURI> jarFile;
  if (NS_FAILED(aJAR->GetJARFile(getter_AddRefs(jarFile)))) {
    return nullptr;
  }
  nsCOMPtr<nsIFileURL> fileUrl = do_QueryInterface(jarFile);
  if (!fileUrl) {
    return nullptr;
  }
  nsCOMPtr<nsIFile> file;
  fileUrl->GetFile(getter_AddRefs(file));
  if (!file) {
    return nullptr;
  }
  RefPtr<nsZipArchive> archive = Omnijar::GetReader(file);
  if (archive) {
    nsCString path;
    aJAR->GetJAREntry(path);
    nsZipItem* item = archive->GetItem(path);
    if (item && item->Compression() == 0 && item->Size() > 0) {
      // We do NOT own this data, but it won't go away until the omnijar
      // file is closed during shutdown.
      const uint8_t* data = archive->GetData(item);
      if (data) {
        *aLength = item->Size();
        return data;
      }
    }
  }
  return nullptr;
}

static ipc::ReadOnlySharedMemoryMapping GetHyphDictFromParent(nsIURI* aURI) {
  MOZ_ASSERT(!XRE_IsParentProcess());
  ipc::ReadOnlySharedMemoryHandle handle;
  MOZ_ASSERT(aURI);
  if (!dom::ContentChild::GetSingleton()->SendGetHyphDict(aURI, &handle)) {
    return nullptr;
  }
  if (!handle.IsValid()) {
    return nullptr;
  }
  auto map = handle.Map();
  if (!map) {
    return nullptr;
  }
  if (!map.Address()) {
    return nullptr;
  }
  return map;
}

static ipc::ReadOnlySharedMemoryHandle CopyToShmem(const CompiledData* aData) {
  MOZ_ASSERT(XRE_IsParentProcess());

  // The shm-related calls here are not expected to fail, but if they do,
  // we'll just return null (as if the resource was unavailable) and proceed
  // without hyphenation.
  uint32_t size = mapped_hyph_compiled_data_size(aData);
  auto handle = ipc::shared_memory::CreateFreezable(size);
  if (!handle) {
    return nullptr;
  }
  auto map = std::move(handle).Map();
  if (!map) {
    return nullptr;
  }
  char* buffer = map.DataAs<char>();
  if (!buffer) {
    return nullptr;
  }

  memcpy(buffer, mapped_hyph_compiled_data_ptr(aData), size);
  return std::move(map).Freeze();
}

static ipc::ReadOnlySharedMemoryHandle LoadFromURI(nsIURI* aURI,
                                                   bool aPrecompiled) {
  MOZ_ASSERT(XRE_IsParentProcess());
  nsCOMPtr<nsIChannel> channel;
  if (NS_FAILED(NS_NewChannel(
          getter_AddRefs(channel), aURI, nsContentUtils::GetSystemPrincipal(),
          nsILoadInfo::SEC_ALLOW_CROSS_ORIGIN_SEC_CONTEXT_IS_NULL,
          nsIContentPolicy::TYPE_OTHER))) {
    return nullptr;
  }
  nsCOMPtr<nsIInputStream> instream;
  if (NS_FAILED(channel->Open(getter_AddRefs(instream)))) {
    return nullptr;
  }
  // Check size, bail out if it is excessively large (the largest of the
  // hyphenation files currently shipped with Firefox is around 1MB
  // uncompressed).
  uint64_t available;
  if (NS_FAILED(instream->Available(&available)) || !available ||
      available > 16 * 1024 * 1024) {
    return nullptr;
  }

  if (aPrecompiled) {
    auto handle = ipc::shared_memory::CreateFreezable(available);
    if (!handle) {
      return nullptr;
    }
    auto map = std::move(handle).Map();
    if (!map) {
      return nullptr;
    }
    char* buffer = map.DataAs<char>();
    if (!buffer) {
      return nullptr;
    }

    uint32_t bytesRead = 0;
    if (NS_FAILED(instream->Read(buffer, available, &bytesRead)) ||
        bytesRead != available) {
      return nullptr;
    }

    if (!mapped_hyph_is_valid_hyphenator(
            reinterpret_cast<const uint8_t*>(buffer), bytesRead)) {
      return nullptr;
    }

    return std::move(map).Freeze();
  }

  // Read from the URI into a temporary buffer, compile it, then copy the
  // compiled resource to a shared memory region.
  auto buffer = MakeUnique<char[]>(available);
  uint32_t bytesRead = 0;
  if (NS_FAILED(instream->Read(buffer.get(), available, &bytesRead)) ||
      bytesRead != available) {
    return nullptr;
  }

  UniquePtr<const CompiledData> data(mapped_hyph_compile_buffer(
      reinterpret_cast<const uint8_t*>(buffer.get()), bytesRead, false));
  if (data) {
    return CopyToShmem(data.get());
  }

  return nullptr;
}

nsHyphenator::nsHyphenator(nsIURI* aURI, bool aHyphenateCapitalized)
    : mDict(Span<const uint8_t>()),
      mHyphenateCapitalized(aHyphenateCapitalized) {
  // Files with extension ".hyf" are expected to be precompiled mapped_hyph
  // tables; we also support uncompiled ".dic" files, but they are more
  // expensive to process on first load.
  nsAutoCString path;
  aURI->GetFilePath(path);
  bool precompiled = StringEndsWith(path, ".hyf"_ns);

  // Content processes don't do compilation; they depend on the parent giving
  // them a compiled version of the resource, so that we only pay the cost of
  // compilation once per language per session.
  if (!precompiled && !XRE_IsParentProcess()) {
    auto shm = GetHyphDictFromParent(aURI);
    if (shm) {
      // We don't need to validate mDict because the parent process
      // will have done so.
      mDict.emplace<ipc::ReadOnlySharedMemoryMapping>(std::move(shm));
    }
    return;
  }

  nsCOMPtr<nsIJARURI> jar = do_QueryInterface(aURI);
  if (jar) {
    // This gives us a raw pointer into the omnijar's data (if uncompressed);
    // we do not own it and must not attempt to free it!
    uint32_t length;
    const uint8_t* ptr = GetItemPtrFromJarURI(jar, &length);
    if (ptr) {
      if (precompiled) {
        // The data should be directly usable by mapped_hyph; validate that it
        // looks correct, and save the pointer.
        if (mapped_hyph_is_valid_hyphenator(ptr, length)) {
          mDict.emplace<Span<const uint8_t>>(ptr, length);
          return;
        }
      } else {
        // The data is an uncompiled pattern file, so we need to compile it.
        // We then move it to shared memory so we can expose it to content
        // processes.
        MOZ_ASSERT(XRE_IsParentProcess());
        UniquePtr<const CompiledData> data(
            mapped_hyph_compile_buffer(ptr, length, false));
        if (data) {
          auto shm = CopyToShmem(data.get());
          if (shm) {
            mDict.emplace<ipc::ReadOnlySharedMemoryHandle>(std::move(shm));
            return;
          }
        }
      }
    } else {
      // Omnijar must be compressed (currently this is the case on Android).
      // If we're the parent process, decompress the resource into a shmem
      // buffer; if we're a child, send a request to the parent for the
      // shared-memory copy (which it will load if not already available).
      if (XRE_IsParentProcess()) {
        auto shm = LoadFromURI(aURI, precompiled);
        if (shm) {
          mDict.emplace<ipc::ReadOnlySharedMemoryHandle>(std::move(shm));
          return;
        }
      } else {
        auto shm = GetHyphDictFromParent(aURI);
        if (shm) {
          // We don't need to validate mDict because the parent process
          // will have done so.
          mDict.emplace<ipc::ReadOnlySharedMemoryMapping>(std::move(shm));
          return;
        }
      }
    }
  }

  // We get file:// URIs when running an unpackaged build; they could also
  // occur if we support adding hyphenation dictionaries by putting files in
  // a directory of the profile, for example.
  if (aURI->SchemeIs("file")) {
    // Ask the Rust lib to mmap the file. In this case our mDictSize field
    // remains zero; mDict is not a pointer to the raw data but an opaque
    // reference to a Rust object, and can only be freed by passing it to
    // mapped_hyph_free_dictionary().
    // (This case occurs in unpackaged developer builds.)
#if XP_WIN
    // GetFilePath returns the path with an unexpected leading slash (like
    // "/c:/path/to/firefox/...") that may prevent it being found if it's an
    // absolute Windows path starting with a drive letter.
    // So check for this case and strip the slash.
    if (path.Length() > 2 && path[0] == '/' && path[2] == ':') {
      path.Cut(0, 1);
    }
#endif
    // In case of %-escaped spaces or other "special" chars in the path,
    // we need the unescaped version to pass to mapped_hyph_load_dictionary.
    NS_UnescapeURL(path);
    if (precompiled) {
      // If the file is compiled, we can just map it directly.
      UniquePtr<const HyphDic> dic(mapped_hyph_load_dictionary(path.get()));
      if (dic) {
        mDict = AsVariant(std::move(dic));
        return;
      }
    } else {
      // For an uncompiled .dic file, the parent process is responsible for
      // compiling it and storing the result in a shmem block that can be
      // shared to content processes.
      MOZ_ASSERT(XRE_IsParentProcess());
      MOZ_ASSERT(StringEndsWith(path, ".dic"_ns));
      UniquePtr<const CompiledData> data(
          mapped_hyph_compile_file(path.get(), false));
      if (data) {
        auto shm = CopyToShmem(data.get());
        if (shm) {
          mDict.emplace<ipc::ReadOnlySharedMemoryHandle>(std::move(shm));
          return;
        }
      }
    }
  }

  // Each loading branch above will return if successful. So if we get here,
  // whichever load type we attempted must have failed because something about
  // the resource is broken.
  nsAutoCString msg;
  aURI->GetSpec(msg);
  msg.Insert("Invalid hyphenation resource: ", 0);
  NS_ASSERTION(false, msg.get());
}

bool nsHyphenator::IsValid() {
  return mDict.match(
      [](Span<const uint8_t>& span) { return !span.IsEmpty(); },
      [](ipc::ReadOnlySharedMemoryHandle& shm) { return shm.IsValid(); },
      [](ipc::ReadOnlySharedMemoryMapping& shm) { return shm.IsValid(); },
      [](UniquePtr<const HyphDic>& hyph) { return hyph != nullptr; });
}

nsresult nsHyphenator::Hyphenate(const nsAString& aString,
                                 nsTArray<bool>& aHyphens) {
  if (!aHyphens.SetLength(aString.Length(), fallible)) {
    return NS_ERROR_OUT_OF_MEMORY;
  }
  memset(aHyphens.Elements(), false, aHyphens.Length() * sizeof(bool));

  bool inWord = false;
  uint32_t wordStart = 0, wordLimit = 0;
  uint32_t chLen;
  for (uint32_t i = 0; i < aString.Length(); i += chLen) {
    uint32_t ch = aString[i];
    chLen = 1;

    if (NS_IS_HIGH_SURROGATE(ch)) {
      if (i + 1 < aString.Length() && NS_IS_LOW_SURROGATE(aString[i + 1])) {
        ch = SURROGATE_TO_UCS4(ch, aString[i + 1]);
        chLen = 2;
      } else {
        NS_WARNING("unpaired surrogate found during hyphenation");
      }
    }

    nsUGenCategory cat = unicode::GetGenCategory(ch);
    if (cat == nsUGenCategory::kLetter || cat == nsUGenCategory::kMark) {
      if (!inWord) {
        inWord = true;
        wordStart = i;
      }
      wordLimit = i + chLen;
      if (i + chLen < aString.Length()) {
        continue;
      }
    }

    if (inWord) {
      HyphenateWord(aString, wordStart, wordLimit, aHyphens);
      inWord = false;
    }
  }

  return NS_OK;
}

void nsHyphenator::HyphenateWord(const nsAString& aString, uint32_t aStart,
                                 uint32_t aLimit, nsTArray<bool>& aHyphens) {
  // Convert word from aStart and aLimit in aString to utf-8 for mapped_hyph,
  // lowercasing it as we go so that it will match the (lowercased) patterns
  // (bug 1105644).
  nsAutoCString utf8;
  const char16_t* cur = aString.BeginReading() + aStart;
  const char16_t* end = aString.BeginReading() + aLimit;
  bool firstLetter = true;
  while (cur < end) {
    uint32_t ch = *cur++;

    if (NS_IS_HIGH_SURROGATE(ch)) {
      if (cur < end && NS_IS_LOW_SURROGATE(*cur)) {
        ch = SURROGATE_TO_UCS4(ch, *cur++);
      } else {
        return;  // unpaired surrogate: bail out, don't hyphenate broken text
      }
    } else if (NS_IS_LOW_SURROGATE(ch)) {
      return;  // unpaired surrogate
    }

    // XXX What about language-specific casing? Consider Turkish I/i...
    // In practice, it looks like the current patterns will not be
    // affected by this, as they treat dotted and undotted i similarly.
    uint32_t origCh = ch;
    ch = ToLowerCase(ch);

    if (ch != origCh) {
      // Avoid hyphenating capitalized words (bug 1550532) unless explicitly
      // allowed by prefs for the language in use.
      // Also never auto-hyphenate a word that has internal caps, as it may
      // well be an all-caps acronym or a quirky name like iTunes.
      if (!mHyphenateCapitalized || !firstLetter) {
        return;
      }
    }
    firstLetter = false;

    if (ch < 0x80) {  // U+0000 - U+007F
      utf8.Append(ch);
    } else if (ch < 0x0800) {  // U+0100 - U+07FF
      utf8.Append(0xC0 | (ch >> 6));
      utf8.Append(0x80 | (0x003F & ch));
    } else if (ch < 0x10000) {  // U+0800 - U+D7FF,U+E000 - U+FFFF
      utf8.Append(0xE0 | (ch >> 12));
      utf8.Append(0x80 | (0x003F & (ch >> 6)));
      utf8.Append(0x80 | (0x003F & ch));
    } else {
      utf8.Append(0xF0 | (ch >> 18));
      utf8.Append(0x80 | (0x003F & (ch >> 12)));
      utf8.Append(0x80 | (0x003F & (ch >> 6)));
      utf8.Append(0x80 | (0x003F & ch));
    }
  }

  AutoTArray<uint8_t, 200> hyphenValues;
  hyphenValues.SetLength(utf8.Length());
  int32_t result = mDict.match(
      [&](Span<const uint8_t>& span) {
        return mapped_hyph_find_hyphen_values_raw(
            span.data(), span.size(), utf8.BeginReading(), utf8.Length(),
            hyphenValues.Elements(), hyphenValues.Length());
      },
      [&](ipc::ReadOnlySharedMemoryHandle& shm) {
        // Only the parent process can have a handle stored. We should never
        // get to this point with just a handle.
        MOZ_ASSERT_UNREACHABLE("Unexpected HyphenateWord with only a handle");
        return 0;
      },
      [&](ipc::ReadOnlySharedMemoryMapping& shm) {
        return mapped_hyph_find_hyphen_values_raw(
            shm.DataAs<uint8_t>(), shm.Size(), utf8.BeginReading(),
            utf8.Length(), hyphenValues.Elements(), hyphenValues.Length());
      },
      [&](UniquePtr<const HyphDic>& hyph) {
        return mapped_hyph_find_hyphen_values_dic(
            hyph.get(), utf8.BeginReading(), utf8.Length(),
            hyphenValues.Elements(), hyphenValues.Length());
      });
  if (result > 0) {
    // We need to convert UTF-8 indexing as used by the hyphenation lib into
    // UTF-16 indexing of the aHyphens[] array for Gecko.
    uint32_t utf16index = 0;
    for (uint32_t utf8index = 0; utf8index < utf8.Length();) {
      // We know utf8 is valid, so we only need to look at the first byte of
      // each character to determine its length and the corresponding UTF-16
      // length to add to utf16index.
      const uint8_t leadByte = utf8[utf8index];
      if (leadByte < 0x80) {
        utf8index += 1;
      } else if (leadByte < 0xE0) {
        utf8index += 2;
      } else if (leadByte < 0xF0) {
        utf8index += 3;
      } else {
        utf8index += 4;
      }
      // The hyphenation value of interest is the one for the last code unit
      // of the utf-8 character, and is recorded on the last code unit of the
      // utf-16 character (in the case of a surrogate pair).
      utf16index += leadByte >= 0xF0 ? 2 : 1;
      if (utf16index > 0 && (hyphenValues[utf8index - 1] & 0x01)) {
        aHyphens[aStart + utf16index - 1] = true;
      }
    }
  }
}

ipc::ReadOnlySharedMemoryHandle nsHyphenator::CloneHandle() {
  MOZ_ASSERT(XRE_IsParentProcess());

  if (mDict.is<ipc::ReadOnlySharedMemoryHandle>()) {
    return mDict.as<ipc::ReadOnlySharedMemoryHandle>().Clone();
  }
  return nullptr;
}