Create dex subdirectory

Move all the DexFile related source to a common subdirectory dex/ of
runtime.

Bug: 71361973
Test: make -j 50 test-art-host
Change-Id: I59e984ed660b93e0776556308be3d653722f5223
diff --git a/runtime/dex/dex_file_loader.h b/runtime/dex/dex_file_loader.h
new file mode 100644
index 0000000..7db8d8e
--- /dev/null
+++ b/runtime/dex/dex_file_loader.h
@@ -0,0 +1,205 @@
+/*
+ * Copyright (C) 2017 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#ifndef ART_RUNTIME_DEX_DEX_FILE_LOADER_H_
+#define ART_RUNTIME_DEX_DEX_FILE_LOADER_H_
+
+#include <cstdint>
+#include <memory>
+#include <string>
+#include <vector>
+
+namespace art {
+
+class DexFile;
+class DexFileContainer;
+class MemMap;
+class OatDexFile;
+class ZipArchive;
+
+// Class that is used to open dex files and deal with corresponding multidex and location logic.
+class DexFileLoader {
+ public:
+  // name of the DexFile entry within a zip archive
+  static constexpr const char* kClassesDex = "classes.dex";
+
+  // The separator character in MultiDex locations.
+  static constexpr char kMultiDexSeparator = '!';
+
+  // Return true if the magic is valid for dex or cdex.
+  static bool IsMagicValid(uint32_t magic);
+  static bool IsMagicValid(const uint8_t* magic);
+
+  // Return true if the corresponding version and magic is valid.
+  static bool IsVersionAndMagicValid(const uint8_t* magic);
+
+  // Returns the checksums of a file for comparison with GetLocationChecksum().
+  // For .dex files, this is the single header checksum.
+  // For zip files, this is the zip entry CRC32 checksum for classes.dex and
+  // each additional multidex entry classes2.dex, classes3.dex, etc.
+  // If a valid zip_fd is provided the file content will be read directly from
+  // the descriptor and `filename` will be used as alias for error logging. If
+  // zip_fd is -1, the method will try to open the `filename` and read the
+  // content from it.
+  // Return true if the checksums could be found, false otherwise.
+  static bool GetMultiDexChecksums(const char* filename,
+                                   std::vector<uint32_t>* checksums,
+                                   std::string* error_msg,
+                                   int zip_fd = -1);
+
+  // Check whether a location denotes a multidex dex file. This is a very simple check: returns
+  // whether the string contains the separator character.
+  static bool IsMultiDexLocation(const char* location);
+
+  // Opens .dex file, backed by existing memory
+  static std::unique_ptr<const DexFile> Open(const uint8_t* base,
+                                             size_t size,
+                                             const std::string& location,
+                                             uint32_t location_checksum,
+                                             const OatDexFile* oat_dex_file,
+                                             bool verify,
+                                             bool verify_checksum,
+                                             std::string* error_msg);
+
+  // Opens .dex file that has been memory-mapped by the caller.
+  static std::unique_ptr<const DexFile> Open(const std::string& location,
+                                             uint32_t location_checkum,
+                                             std::unique_ptr<MemMap> mem_map,
+                                             bool verify,
+                                             bool verify_checksum,
+                                             std::string* error_msg);
+
+  // Opens all .dex files found in the file, guessing the container format based on file extension.
+  static bool Open(const char* filename,
+                   const std::string& location,
+                   bool verify,
+                   bool verify_checksum,
+                   std::string* error_msg,
+                   std::vector<std::unique_ptr<const DexFile>>* dex_files);
+
+  // Open a single dex file from an fd. This function closes the fd.
+  static std::unique_ptr<const DexFile> OpenDex(int fd,
+                                                const std::string& location,
+                                                bool verify,
+                                                bool verify_checksum,
+                                                std::string* error_msg);
+
+  // Opens dex files from within a .jar, .zip, or .apk file
+  static bool OpenZip(int fd,
+                      const std::string& location,
+                      bool verify,
+                      bool verify_checksum,
+                      std::string* error_msg,
+                      std::vector<std::unique_ptr<const DexFile>>* dex_files);
+
+  // Return the name of the index-th classes.dex in a multidex zip file. This is classes.dex for
+  // index == 0, and classes{index + 1}.dex else.
+  static std::string GetMultiDexClassesDexName(size_t index);
+
+  // Return the (possibly synthetic) dex location for a multidex entry. This is dex_location for
+  // index == 0, and dex_location + multi-dex-separator + GetMultiDexClassesDexName(index) else.
+  static std::string GetMultiDexLocation(size_t index, const char* dex_location);
+
+  // Returns the canonical form of the given dex location.
+  //
+  // There are different flavors of "dex locations" as follows:
+  // the file name of a dex file:
+  //     The actual file path that the dex file has on disk.
+  // dex_location:
+  //     This acts as a key for the class linker to know which dex file to load.
+  //     It may correspond to either an old odex file or a particular dex file
+  //     inside an oat file. In the first case it will also match the file name
+  //     of the dex file. In the second case (oat) it will include the file name
+  //     and possibly some multidex annotation to uniquely identify it.
+  // canonical_dex_location:
+  //     the dex_location where it's file name part has been made canonical.
+  static std::string GetDexCanonicalLocation(const char* dex_location);
+
+  // For normal dex files, location and base location coincide. If a dex file is part of a multidex
+  // archive, the base location is the name of the originating jar/apk, stripped of any internal
+  // classes*.dex path.
+  static std::string GetBaseLocation(const char* location) {
+    const char* pos = strrchr(location, kMultiDexSeparator);
+    return (pos == nullptr) ? location : std::string(location, pos - location);
+  }
+
+  static std::string GetBaseLocation(const std::string& location) {
+    return GetBaseLocation(location.c_str());
+  }
+
+  // Returns the '!classes*.dex' part of the dex location. Returns an empty
+  // string if there is no multidex suffix for the given location.
+  // The kMultiDexSeparator is included in the returned suffix.
+  static std::string GetMultiDexSuffix(const std::string& location) {
+    size_t pos = location.rfind(kMultiDexSeparator);
+    return (pos == std::string::npos) ? std::string() : location.substr(pos);
+  }
+
+ private:
+  static std::unique_ptr<const DexFile> OpenFile(int fd,
+                                                 const std::string& location,
+                                                 bool verify,
+                                                 bool verify_checksum,
+                                                 std::string* error_msg);
+
+  enum class ZipOpenErrorCode {
+    kNoError,
+    kEntryNotFound,
+    kExtractToMemoryError,
+    kDexFileError,
+    kMakeReadOnlyError,
+    kVerifyError
+  };
+
+  // Open all classesXXX.dex files from a zip archive.
+  static bool OpenAllDexFilesFromZip(const ZipArchive& zip_archive,
+                                     const std::string& location,
+                                     bool verify,
+                                     bool verify_checksum,
+                                     std::string* error_msg,
+                                     std::vector<std::unique_ptr<const DexFile>>* dex_files);
+
+  // Opens .dex file from the entry_name in a zip archive. error_code is undefined when non-null
+  // return.
+  static std::unique_ptr<const DexFile> OpenOneDexFileFromZip(const ZipArchive& zip_archive,
+                                                              const char* entry_name,
+                                                              const std::string& location,
+                                                              bool verify,
+                                                              bool verify_checksum,
+                                                              std::string* error_msg,
+                                                              ZipOpenErrorCode* error_code);
+
+  enum class VerifyResult {  // private
+    kVerifyNotAttempted,
+    kVerifySucceeded,
+    kVerifyFailed
+  };
+
+  static std::unique_ptr<DexFile> OpenCommon(const uint8_t* base,
+                                             size_t size,
+                                             const std::string& location,
+                                             uint32_t location_checksum,
+                                             const OatDexFile* oat_dex_file,
+                                             bool verify,
+                                             bool verify_checksum,
+                                             std::string* error_msg,
+                                             DexFileContainer* container,
+                                             VerifyResult* verify_result);
+};
+
+}  // namespace art
+
+#endif  // ART_RUNTIME_DEX_DEX_FILE_LOADER_H_