1/*
2 * Copyright (C) 2011 The Android Open Source Project
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 *      http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16
17#include "dex_file.h"
18
19#include <fcntl.h>
20#include <limits.h>
21#include <stdio.h>
22#include <stdlib.h>
23#include <string.h>
24#include <sys/file.h>
25#include <sys/stat.h>
26#include <memory>
27
28#include "base/logging.h"
29#include "base/stringprintf.h"
30#include "class_linker.h"
31#include "dex_file-inl.h"
32#include "dex_file_verifier.h"
33#include "globals.h"
34#include "leb128.h"
35#include "mirror/art_field-inl.h"
36#include "mirror/art_method-inl.h"
37#include "mirror/string.h"
38#include "os.h"
39#include "safe_map.h"
40#include "ScopedFd.h"
41#include "handle_scope-inl.h"
42#include "thread.h"
43#include "utf-inl.h"
44#include "utils.h"
45#include "well_known_classes.h"
46#include "zip_archive.h"
47
48namespace art {
49
50const byte DexFile::kDexMagic[] = { 'd', 'e', 'x', '\n' };
51const byte DexFile::kDexMagicVersion[] = { '0', '3', '5', '\0' };
52
53static int OpenAndReadMagic(const char* filename, uint32_t* magic, std::string* error_msg) {
54  CHECK(magic != NULL);
55  ScopedFd fd(open(filename, O_RDONLY, 0));
56  if (fd.get() == -1) {
57    *error_msg = StringPrintf("Unable to open '%s' : %s", filename, strerror(errno));
58    return -1;
59  }
60  int n = TEMP_FAILURE_RETRY(read(fd.get(), magic, sizeof(*magic)));
61  if (n != sizeof(*magic)) {
62    *error_msg = StringPrintf("Failed to find magic in '%s'", filename);
63    return -1;
64  }
65  if (lseek(fd.get(), 0, SEEK_SET) != 0) {
66    *error_msg = StringPrintf("Failed to seek to beginning of file '%s' : %s", filename,
67                              strerror(errno));
68    return -1;
69  }
70  return fd.release();
71}
72
73bool DexFile::GetChecksum(const char* filename, uint32_t* checksum, std::string* error_msg) {
74  CHECK(checksum != NULL);
75  uint32_t magic;
76
77  // Strip ":...", which is the location
78  const char* zip_entry_name = kClassesDex;
79  const char* file_part = filename;
80  std::string file_part_storage;
81
82  if (DexFile::IsMultiDexLocation(filename)) {
83    file_part_storage = GetBaseLocation(filename);
84    file_part = file_part_storage.c_str();
85    zip_entry_name = filename + file_part_storage.size() + 1;
86    DCHECK_EQ(zip_entry_name[-1], kMultiDexSeparator);
87  }
88
89  ScopedFd fd(OpenAndReadMagic(file_part, &magic, error_msg));
90  if (fd.get() == -1) {
91    DCHECK(!error_msg->empty());
92    return false;
93  }
94  if (IsZipMagic(magic)) {
95    std::unique_ptr<ZipArchive> zip_archive(ZipArchive::OpenFromFd(fd.release(), filename, error_msg));
96    if (zip_archive.get() == NULL) {
97      *error_msg = StringPrintf("Failed to open zip archive '%s'", file_part);
98      return false;
99    }
100    std::unique_ptr<ZipEntry> zip_entry(zip_archive->Find(zip_entry_name, error_msg));
101    if (zip_entry.get() == NULL) {
102      *error_msg = StringPrintf("Zip archive '%s' doesn't contain %s (error msg: %s)", file_part,
103                                zip_entry_name, error_msg->c_str());
104      return false;
105    }
106    *checksum = zip_entry->GetCrc32();
107    return true;
108  }
109  if (IsDexMagic(magic)) {
110    std::unique_ptr<const DexFile> dex_file(DexFile::OpenFile(fd.release(), filename, false, error_msg));
111    if (dex_file.get() == NULL) {
112      return false;
113    }
114    *checksum = dex_file->GetHeader().checksum_;
115    return true;
116  }
117  *error_msg = StringPrintf("Expected valid zip or dex file: '%s'", filename);
118  return false;
119}
120
121bool DexFile::Open(const char* filename, const char* location, std::string* error_msg,
122                   std::vector<const DexFile*>* dex_files) {
123  uint32_t magic;
124  ScopedFd fd(OpenAndReadMagic(filename, &magic, error_msg));
125  if (fd.get() == -1) {
126    DCHECK(!error_msg->empty());
127    return false;
128  }
129  if (IsZipMagic(magic)) {
130    return DexFile::OpenZip(fd.release(), location, error_msg, dex_files);
131  }
132  if (IsDexMagic(magic)) {
133    std::unique_ptr<const DexFile> dex_file(DexFile::OpenFile(fd.release(), location, true,
134                                                              error_msg));
135    if (dex_file.get() != nullptr) {
136      dex_files->push_back(dex_file.release());
137      return true;
138    } else {
139      return false;
140    }
141  }
142  *error_msg = StringPrintf("Expected valid zip or dex file: '%s'", filename);
143  return false;
144}
145
146int DexFile::GetPermissions() const {
147  if (mem_map_.get() == NULL) {
148    return 0;
149  } else {
150    return mem_map_->GetProtect();
151  }
152}
153
154bool DexFile::IsReadOnly() const {
155  return GetPermissions() == PROT_READ;
156}
157
158bool DexFile::EnableWrite() const {
159  CHECK(IsReadOnly());
160  if (mem_map_.get() == NULL) {
161    return false;
162  } else {
163    return mem_map_->Protect(PROT_READ | PROT_WRITE);
164  }
165}
166
167bool DexFile::DisableWrite() const {
168  CHECK(!IsReadOnly());
169  if (mem_map_.get() == NULL) {
170    return false;
171  } else {
172    return mem_map_->Protect(PROT_READ);
173  }
174}
175
176const DexFile* DexFile::OpenFile(int fd, const char* location, bool verify,
177                                 std::string* error_msg) {
178  CHECK(location != nullptr);
179  std::unique_ptr<MemMap> map;
180  {
181    ScopedFd delayed_close(fd);
182    struct stat sbuf;
183    memset(&sbuf, 0, sizeof(sbuf));
184    if (fstat(fd, &sbuf) == -1) {
185      *error_msg = StringPrintf("DexFile: fstat '%s' failed: %s", location, strerror(errno));
186      return nullptr;
187    }
188    if (S_ISDIR(sbuf.st_mode)) {
189      *error_msg = StringPrintf("Attempt to mmap directory '%s'", location);
190      return nullptr;
191    }
192    size_t length = sbuf.st_size;
193    map.reset(MemMap::MapFile(length, PROT_READ, MAP_PRIVATE, fd, 0, location, error_msg));
194    if (map.get() == nullptr) {
195      DCHECK(!error_msg->empty());
196      return nullptr;
197    }
198  }
199
200  if (map->Size() < sizeof(DexFile::Header)) {
201    *error_msg = StringPrintf(
202        "DexFile: failed to open dex file '%s' that is too short to have a header", location);
203    return nullptr;
204  }
205
206  const Header* dex_header = reinterpret_cast<const Header*>(map->Begin());
207
208  const DexFile* dex_file = OpenMemory(location, dex_header->checksum_, map.release(), error_msg);
209  if (dex_file == nullptr) {
210    *error_msg = StringPrintf("Failed to open dex file '%s' from memory: %s", location,
211                              error_msg->c_str());
212    return nullptr;
213  }
214
215  if (verify && !DexFileVerifier::Verify(dex_file, dex_file->Begin(), dex_file->Size(), location,
216                                         error_msg)) {
217    return nullptr;
218  }
219
220  return dex_file;
221}
222
223const char* DexFile::kClassesDex = "classes.dex";
224
225bool DexFile::OpenZip(int fd, const std::string& location, std::string* error_msg,
226                      std::vector<const  DexFile*>* dex_files) {
227  std::unique_ptr<ZipArchive> zip_archive(ZipArchive::OpenFromFd(fd, location.c_str(), error_msg));
228  if (zip_archive.get() == nullptr) {
229    DCHECK(!error_msg->empty());
230    return false;
231  }
232  return DexFile::OpenFromZip(*zip_archive, location, error_msg, dex_files);
233}
234
235const DexFile* DexFile::OpenMemory(const std::string& location,
236                                   uint32_t location_checksum,
237                                   MemMap* mem_map,
238                                   std::string* error_msg) {
239  return OpenMemory(mem_map->Begin(),
240                    mem_map->Size(),
241                    location,
242                    location_checksum,
243                    mem_map,
244                    error_msg);
245}
246
247const DexFile* DexFile::Open(const ZipArchive& zip_archive, const char* entry_name,
248                             const std::string& location, std::string* error_msg,
249                             ZipOpenErrorCode* error_code) {
250  CHECK(!location.empty());
251  std::unique_ptr<ZipEntry> zip_entry(zip_archive.Find(entry_name, error_msg));
252  if (zip_entry.get() == NULL) {
253    *error_code = ZipOpenErrorCode::kEntryNotFound;
254    return nullptr;
255  }
256  std::unique_ptr<MemMap> map(zip_entry->ExtractToMemMap(location.c_str(), entry_name, error_msg));
257  if (map.get() == NULL) {
258    *error_msg = StringPrintf("Failed to extract '%s' from '%s': %s", entry_name, location.c_str(),
259                              error_msg->c_str());
260    *error_code = ZipOpenErrorCode::kExtractToMemoryError;
261    return nullptr;
262  }
263  std::unique_ptr<const DexFile> dex_file(OpenMemory(location, zip_entry->GetCrc32(), map.release(),
264                                               error_msg));
265  if (dex_file.get() == nullptr) {
266    *error_msg = StringPrintf("Failed to open dex file '%s' from memory: %s", location.c_str(),
267                              error_msg->c_str());
268    *error_code = ZipOpenErrorCode::kDexFileError;
269    return nullptr;
270  }
271  if (!dex_file->DisableWrite()) {
272    *error_msg = StringPrintf("Failed to make dex file '%s' read only", location.c_str());
273    *error_code = ZipOpenErrorCode::kMakeReadOnlyError;
274    return nullptr;
275  }
276  CHECK(dex_file->IsReadOnly()) << location;
277  if (!DexFileVerifier::Verify(dex_file.get(), dex_file->Begin(), dex_file->Size(),
278                               location.c_str(), error_msg)) {
279    *error_code = ZipOpenErrorCode::kVerifyError;
280    return nullptr;
281  }
282  *error_code = ZipOpenErrorCode::kNoError;
283  return dex_file.release();
284}
285
286bool DexFile::OpenFromZip(const ZipArchive& zip_archive, const std::string& location,
287                          std::string* error_msg, std::vector<const DexFile*>* dex_files) {
288  ZipOpenErrorCode error_code;
289  std::unique_ptr<const DexFile> dex_file(Open(zip_archive, kClassesDex, location, error_msg,
290                                               &error_code));
291  if (dex_file.get() == nullptr) {
292    return false;
293  } else {
294    // Had at least classes.dex.
295    dex_files->push_back(dex_file.release());
296
297    // Now try some more.
298    size_t i = 2;
299
300    // We could try to avoid std::string allocations by working on a char array directly. As we
301    // do not expect a lot of iterations, this seems too involved and brittle.
302
303    while (i < 100) {
304      std::string name = StringPrintf("classes%zu.dex", i);
305      std::string fake_location = location + kMultiDexSeparator + name;
306      std::unique_ptr<const DexFile> next_dex_file(Open(zip_archive, name.c_str(), fake_location,
307                                                        error_msg, &error_code));
308      if (next_dex_file.get() == nullptr) {
309        if (error_code != ZipOpenErrorCode::kEntryNotFound) {
310          LOG(WARNING) << error_msg;
311        }
312        break;
313      } else {
314        dex_files->push_back(next_dex_file.release());
315      }
316
317      i++;
318    }
319
320    return true;
321  }
322}
323
324
325const DexFile* DexFile::OpenMemory(const byte* base,
326                                   size_t size,
327                                   const std::string& location,
328                                   uint32_t location_checksum,
329                                   MemMap* mem_map, std::string* error_msg) {
330  CHECK_ALIGNED(base, 4);  // various dex file structures must be word aligned
331  std::unique_ptr<DexFile> dex_file(new DexFile(base, size, location, location_checksum, mem_map));
332  if (!dex_file->Init(error_msg)) {
333    return nullptr;
334  } else {
335    return dex_file.release();
336  }
337}
338
339DexFile::DexFile(const byte* base, size_t size,
340                 const std::string& location,
341                 uint32_t location_checksum,
342                 MemMap* mem_map)
343    : begin_(base),
344      size_(size),
345      location_(location),
346      location_checksum_(location_checksum),
347      mem_map_(mem_map),
348      header_(reinterpret_cast<const Header*>(base)),
349      string_ids_(reinterpret_cast<const StringId*>(base + header_->string_ids_off_)),
350      type_ids_(reinterpret_cast<const TypeId*>(base + header_->type_ids_off_)),
351      field_ids_(reinterpret_cast<const FieldId*>(base + header_->field_ids_off_)),
352      method_ids_(reinterpret_cast<const MethodId*>(base + header_->method_ids_off_)),
353      proto_ids_(reinterpret_cast<const ProtoId*>(base + header_->proto_ids_off_)),
354      class_defs_(reinterpret_cast<const ClassDef*>(base + header_->class_defs_off_)),
355      find_class_def_misses_(0),
356      class_def_index_(nullptr),
357      build_class_def_index_mutex_("DexFile index creation mutex") {
358  CHECK(begin_ != NULL) << GetLocation();
359  CHECK_GT(size_, 0U) << GetLocation();
360}
361
362DexFile::~DexFile() {
363  // We don't call DeleteGlobalRef on dex_object_ because we're only called by DestroyJavaVM, and
364  // that's only called after DetachCurrentThread, which means there's no JNIEnv. We could
365  // re-attach, but cleaning up these global references is not obviously useful. It's not as if
366  // the global reference table is otherwise empty!
367  // Remove the index if one were created.
368  delete class_def_index_.LoadRelaxed();
369}
370
371bool DexFile::Init(std::string* error_msg) {
372  if (!CheckMagicAndVersion(error_msg)) {
373    return false;
374  }
375  return true;
376}
377
378bool DexFile::CheckMagicAndVersion(std::string* error_msg) const {
379  if (!IsMagicValid(header_->magic_)) {
380    std::ostringstream oss;
381    oss << "Unrecognized magic number in "  << GetLocation() << ":"
382            << " " << header_->magic_[0]
383            << " " << header_->magic_[1]
384            << " " << header_->magic_[2]
385            << " " << header_->magic_[3];
386    *error_msg = oss.str();
387    return false;
388  }
389  if (!IsVersionValid(header_->magic_)) {
390    std::ostringstream oss;
391    oss << "Unrecognized version number in "  << GetLocation() << ":"
392            << " " << header_->magic_[4]
393            << " " << header_->magic_[5]
394            << " " << header_->magic_[6]
395            << " " << header_->magic_[7];
396    *error_msg = oss.str();
397    return false;
398  }
399  return true;
400}
401
402bool DexFile::IsMagicValid(const byte* magic) {
403  return (memcmp(magic, kDexMagic, sizeof(kDexMagic)) == 0);
404}
405
406bool DexFile::IsVersionValid(const byte* magic) {
407  const byte* version = &magic[sizeof(kDexMagic)];
408  return (memcmp(version, kDexMagicVersion, sizeof(kDexMagicVersion)) == 0);
409}
410
411uint32_t DexFile::GetVersion() const {
412  const char* version = reinterpret_cast<const char*>(&GetHeader().magic_[sizeof(kDexMagic)]);
413  return atoi(version);
414}
415
416const DexFile::ClassDef* DexFile::FindClassDef(const char* descriptor) const {
417  // If we have an index lookup the descriptor via that as its constant time to search.
418  Index* index = class_def_index_.LoadSequentiallyConsistent();
419  if (index != nullptr) {
420    auto it = index->find(descriptor);
421    return (it == index->end()) ? nullptr : it->second;
422  }
423  // Fast path for rate no class defs case.
424  uint32_t num_class_defs = NumClassDefs();
425  if (num_class_defs == 0) {
426    return nullptr;
427  }
428  // Search for class def with 2 binary searches and then a linear search.
429  const StringId* string_id = FindStringId(descriptor);
430  if (string_id != nullptr) {
431    const TypeId* type_id = FindTypeId(GetIndexForStringId(*string_id));
432    if (type_id != nullptr) {
433      uint16_t type_idx = GetIndexForTypeId(*type_id);
434      for (size_t i = 0; i < num_class_defs; ++i) {
435        const ClassDef& class_def = GetClassDef(i);
436        if (class_def.class_idx_ == type_idx) {
437          return &class_def;
438        }
439      }
440    }
441  }
442  // A miss. If we've had kMaxFailedDexClassDefLookups misses then build an index to speed things
443  // up. This isn't done eagerly at construction as construction is not performed in multi-threaded
444  // sections of tools like dex2oat. If we're lazy we hopefully increase the chance of balancing
445  // out which thread builds the index.
446  find_class_def_misses_++;
447  const uint32_t kMaxFailedDexClassDefLookups = 100;
448  if (find_class_def_misses_ > kMaxFailedDexClassDefLookups) {
449    MutexLock mu(Thread::Current(), build_class_def_index_mutex_);
450    // Are we the first ones building the index?
451    if (class_def_index_.LoadSequentiallyConsistent() == nullptr) {
452      index = new Index(num_class_defs);
453      for (uint32_t i = 0; i < num_class_defs;  ++i) {
454        const ClassDef& class_def = GetClassDef(i);
455        const char* descriptor = GetClassDescriptor(class_def);
456        index->insert(std::make_pair(descriptor, &class_def));
457      }
458      class_def_index_.StoreSequentiallyConsistent(index);
459    }
460  }
461  return nullptr;
462}
463
464const DexFile::ClassDef* DexFile::FindClassDef(uint16_t type_idx) const {
465  size_t num_class_defs = NumClassDefs();
466  for (size_t i = 0; i < num_class_defs; ++i) {
467    const ClassDef& class_def = GetClassDef(i);
468    if (class_def.class_idx_ == type_idx) {
469      return &class_def;
470    }
471  }
472  return NULL;
473}
474
475const DexFile::FieldId* DexFile::FindFieldId(const DexFile::TypeId& declaring_klass,
476                                              const DexFile::StringId& name,
477                                              const DexFile::TypeId& type) const {
478  // Binary search MethodIds knowing that they are sorted by class_idx, name_idx then proto_idx
479  const uint16_t class_idx = GetIndexForTypeId(declaring_klass);
480  const uint32_t name_idx = GetIndexForStringId(name);
481  const uint16_t type_idx = GetIndexForTypeId(type);
482  int32_t lo = 0;
483  int32_t hi = NumFieldIds() - 1;
484  while (hi >= lo) {
485    int32_t mid = (hi + lo) / 2;
486    const DexFile::FieldId& field = GetFieldId(mid);
487    if (class_idx > field.class_idx_) {
488      lo = mid + 1;
489    } else if (class_idx < field.class_idx_) {
490      hi = mid - 1;
491    } else {
492      if (name_idx > field.name_idx_) {
493        lo = mid + 1;
494      } else if (name_idx < field.name_idx_) {
495        hi = mid - 1;
496      } else {
497        if (type_idx > field.type_idx_) {
498          lo = mid + 1;
499        } else if (type_idx < field.type_idx_) {
500          hi = mid - 1;
501        } else {
502          return &field;
503        }
504      }
505    }
506  }
507  return NULL;
508}
509
510const DexFile::MethodId* DexFile::FindMethodId(const DexFile::TypeId& declaring_klass,
511                                               const DexFile::StringId& name,
512                                               const DexFile::ProtoId& signature) const {
513  // Binary search MethodIds knowing that they are sorted by class_idx, name_idx then proto_idx
514  const uint16_t class_idx = GetIndexForTypeId(declaring_klass);
515  const uint32_t name_idx = GetIndexForStringId(name);
516  const uint16_t proto_idx = GetIndexForProtoId(signature);
517  int32_t lo = 0;
518  int32_t hi = NumMethodIds() - 1;
519  while (hi >= lo) {
520    int32_t mid = (hi + lo) / 2;
521    const DexFile::MethodId& method = GetMethodId(mid);
522    if (class_idx > method.class_idx_) {
523      lo = mid + 1;
524    } else if (class_idx < method.class_idx_) {
525      hi = mid - 1;
526    } else {
527      if (name_idx > method.name_idx_) {
528        lo = mid + 1;
529      } else if (name_idx < method.name_idx_) {
530        hi = mid - 1;
531      } else {
532        if (proto_idx > method.proto_idx_) {
533          lo = mid + 1;
534        } else if (proto_idx < method.proto_idx_) {
535          hi = mid - 1;
536        } else {
537          return &method;
538        }
539      }
540    }
541  }
542  return NULL;
543}
544
545const DexFile::StringId* DexFile::FindStringId(const char* string) const {
546  int32_t lo = 0;
547  int32_t hi = NumStringIds() - 1;
548  while (hi >= lo) {
549    int32_t mid = (hi + lo) / 2;
550    const DexFile::StringId& str_id = GetStringId(mid);
551    const char* str = GetStringData(str_id);
552    int compare = CompareModifiedUtf8ToModifiedUtf8AsUtf16CodePointValues(string, str);
553    if (compare > 0) {
554      lo = mid + 1;
555    } else if (compare < 0) {
556      hi = mid - 1;
557    } else {
558      return &str_id;
559    }
560  }
561  return NULL;
562}
563
564const DexFile::StringId* DexFile::FindStringId(const uint16_t* string) const {
565  int32_t lo = 0;
566  int32_t hi = NumStringIds() - 1;
567  while (hi >= lo) {
568    int32_t mid = (hi + lo) / 2;
569    const DexFile::StringId& str_id = GetStringId(mid);
570    const char* str = GetStringData(str_id);
571    int compare = CompareModifiedUtf8ToUtf16AsCodePointValues(str, string);
572    if (compare > 0) {
573      lo = mid + 1;
574    } else if (compare < 0) {
575      hi = mid - 1;
576    } else {
577      return &str_id;
578    }
579  }
580  return NULL;
581}
582
583const DexFile::TypeId* DexFile::FindTypeId(uint32_t string_idx) const {
584  int32_t lo = 0;
585  int32_t hi = NumTypeIds() - 1;
586  while (hi >= lo) {
587    int32_t mid = (hi + lo) / 2;
588    const TypeId& type_id = GetTypeId(mid);
589    if (string_idx > type_id.descriptor_idx_) {
590      lo = mid + 1;
591    } else if (string_idx < type_id.descriptor_idx_) {
592      hi = mid - 1;
593    } else {
594      return &type_id;
595    }
596  }
597  return NULL;
598}
599
600const DexFile::ProtoId* DexFile::FindProtoId(uint16_t return_type_idx,
601                                             const uint16_t* signature_type_idxs,
602                                             uint32_t signature_length) const {
603  int32_t lo = 0;
604  int32_t hi = NumProtoIds() - 1;
605  while (hi >= lo) {
606    int32_t mid = (hi + lo) / 2;
607    const DexFile::ProtoId& proto = GetProtoId(mid);
608    int compare = return_type_idx - proto.return_type_idx_;
609    if (compare == 0) {
610      DexFileParameterIterator it(*this, proto);
611      size_t i = 0;
612      while (it.HasNext() && i < signature_length && compare == 0) {
613        compare = signature_type_idxs[i] - it.GetTypeIdx();
614        it.Next();
615        i++;
616      }
617      if (compare == 0) {
618        if (it.HasNext()) {
619          compare = -1;
620        } else if (i < signature_length) {
621          compare = 1;
622        }
623      }
624    }
625    if (compare > 0) {
626      lo = mid + 1;
627    } else if (compare < 0) {
628      hi = mid - 1;
629    } else {
630      return &proto;
631    }
632  }
633  return NULL;
634}
635
636// Given a signature place the type ids into the given vector
637bool DexFile::CreateTypeList(const StringPiece& signature, uint16_t* return_type_idx,
638                             std::vector<uint16_t>* param_type_idxs) const {
639  if (signature[0] != '(') {
640    return false;
641  }
642  size_t offset = 1;
643  size_t end = signature.size();
644  bool process_return = false;
645  while (offset < end) {
646    size_t start_offset = offset;
647    char c = signature[offset];
648    offset++;
649    if (c == ')') {
650      process_return = true;
651      continue;
652    }
653    while (c == '[') {  // process array prefix
654      if (offset >= end) {  // expect some descriptor following [
655        return false;
656      }
657      c = signature[offset];
658      offset++;
659    }
660    if (c == 'L') {  // process type descriptors
661      do {
662        if (offset >= end) {  // unexpected early termination of descriptor
663          return false;
664        }
665        c = signature[offset];
666        offset++;
667      } while (c != ';');
668    }
669    // TODO: avoid creating a std::string just to get a 0-terminated char array
670    std::string descriptor(signature.data() + start_offset, offset - start_offset);
671    const DexFile::StringId* string_id = FindStringId(descriptor.c_str());
672    if (string_id == NULL) {
673      return false;
674    }
675    const DexFile::TypeId* type_id = FindTypeId(GetIndexForStringId(*string_id));
676    if (type_id == NULL) {
677      return false;
678    }
679    uint16_t type_idx = GetIndexForTypeId(*type_id);
680    if (!process_return) {
681      param_type_idxs->push_back(type_idx);
682    } else {
683      *return_type_idx = type_idx;
684      return offset == end;  // return true if the signature had reached a sensible end
685    }
686  }
687  return false;  // failed to correctly parse return type
688}
689
690const Signature DexFile::CreateSignature(const StringPiece& signature) const {
691  uint16_t return_type_idx;
692  std::vector<uint16_t> param_type_indices;
693  bool success = CreateTypeList(signature, &return_type_idx, &param_type_indices);
694  if (!success) {
695    return Signature::NoSignature();
696  }
697  const ProtoId* proto_id = FindProtoId(return_type_idx, param_type_indices);
698  if (proto_id == NULL) {
699    return Signature::NoSignature();
700  }
701  return Signature(this, *proto_id);
702}
703
704int32_t DexFile::GetLineNumFromPC(mirror::ArtMethod* method, uint32_t rel_pc) const {
705  // For native method, lineno should be -2 to indicate it is native. Note that
706  // "line number == -2" is how libcore tells from StackTraceElement.
707  if (method->GetCodeItemOffset() == 0) {
708    return -2;
709  }
710
711  const CodeItem* code_item = GetCodeItem(method->GetCodeItemOffset());
712  DCHECK(code_item != NULL) << PrettyMethod(method) << " " << GetLocation();
713
714  // A method with no line number info should return -1
715  LineNumFromPcContext context(rel_pc, -1);
716  DecodeDebugInfo(code_item, method->IsStatic(), method->GetDexMethodIndex(), LineNumForPcCb,
717                  NULL, &context);
718  return context.line_num_;
719}
720
721int32_t DexFile::FindTryItem(const CodeItem &code_item, uint32_t address) {
722  // Note: Signed type is important for max and min.
723  int32_t min = 0;
724  int32_t max = code_item.tries_size_ - 1;
725
726  while (min <= max) {
727    int32_t mid = min + ((max - min) / 2);
728
729    const art::DexFile::TryItem* ti = GetTryItems(code_item, mid);
730    uint32_t start = ti->start_addr_;
731    uint32_t end = start + ti->insn_count_;
732
733    if (address < start) {
734      max = mid - 1;
735    } else if (address >= end) {
736      min = mid + 1;
737    } else {  // We have a winner!
738      return mid;
739    }
740  }
741  // No match.
742  return -1;
743}
744
745int32_t DexFile::FindCatchHandlerOffset(const CodeItem &code_item, uint32_t address) {
746  int32_t try_item = FindTryItem(code_item, address);
747  if (try_item == -1) {
748    return -1;
749  } else {
750    return DexFile::GetTryItems(code_item, try_item)->handler_off_;
751  }
752}
753
754void DexFile::DecodeDebugInfo0(const CodeItem* code_item, bool is_static, uint32_t method_idx,
755                               DexDebugNewPositionCb position_cb, DexDebugNewLocalCb local_cb,
756                               void* context, const byte* stream, LocalInfo* local_in_reg) const {
757  uint32_t line = DecodeUnsignedLeb128(&stream);
758  uint32_t parameters_size = DecodeUnsignedLeb128(&stream);
759  uint16_t arg_reg = code_item->registers_size_ - code_item->ins_size_;
760  uint32_t address = 0;
761  bool need_locals = (local_cb != NULL);
762
763  if (!is_static) {
764    if (need_locals) {
765      const char* descriptor = GetMethodDeclaringClassDescriptor(GetMethodId(method_idx));
766      local_in_reg[arg_reg].name_ = "this";
767      local_in_reg[arg_reg].descriptor_ = descriptor;
768      local_in_reg[arg_reg].signature_ = NULL;
769      local_in_reg[arg_reg].start_address_ = 0;
770      local_in_reg[arg_reg].is_live_ = true;
771    }
772    arg_reg++;
773  }
774
775  DexFileParameterIterator it(*this, GetMethodPrototype(GetMethodId(method_idx)));
776  for (uint32_t i = 0; i < parameters_size && it.HasNext(); ++i, it.Next()) {
777    if (arg_reg >= code_item->registers_size_) {
778      LOG(ERROR) << "invalid stream - arg reg >= reg size (" << arg_reg
779                 << " >= " << code_item->registers_size_ << ") in " << GetLocation();
780      return;
781    }
782    uint32_t id = DecodeUnsignedLeb128P1(&stream);
783    const char* descriptor = it.GetDescriptor();
784    if (need_locals && id != kDexNoIndex) {
785      const char* name = StringDataByIdx(id);
786      local_in_reg[arg_reg].name_ = name;
787      local_in_reg[arg_reg].descriptor_ = descriptor;
788      local_in_reg[arg_reg].signature_ = NULL;
789      local_in_reg[arg_reg].start_address_ = address;
790      local_in_reg[arg_reg].is_live_ = true;
791    }
792    switch (*descriptor) {
793      case 'D':
794      case 'J':
795        arg_reg += 2;
796        break;
797      default:
798        arg_reg += 1;
799        break;
800    }
801  }
802
803  if (it.HasNext()) {
804    LOG(ERROR) << "invalid stream - problem with parameter iterator in " << GetLocation()
805               << " for method " << PrettyMethod(method_idx, *this);
806    return;
807  }
808
809  for (;;)  {
810    uint8_t opcode = *stream++;
811    uint16_t reg;
812    uint32_t name_idx;
813    uint32_t descriptor_idx;
814    uint32_t signature_idx = 0;
815
816    switch (opcode) {
817      case DBG_END_SEQUENCE:
818        return;
819
820      case DBG_ADVANCE_PC:
821        address += DecodeUnsignedLeb128(&stream);
822        break;
823
824      case DBG_ADVANCE_LINE:
825        line += DecodeSignedLeb128(&stream);
826        break;
827
828      case DBG_START_LOCAL:
829      case DBG_START_LOCAL_EXTENDED:
830        reg = DecodeUnsignedLeb128(&stream);
831        if (reg > code_item->registers_size_) {
832          LOG(ERROR) << "invalid stream - reg > reg size (" << reg << " > "
833                     << code_item->registers_size_ << ") in " << GetLocation();
834          return;
835        }
836
837        name_idx = DecodeUnsignedLeb128P1(&stream);
838        descriptor_idx = DecodeUnsignedLeb128P1(&stream);
839        if (opcode == DBG_START_LOCAL_EXTENDED) {
840          signature_idx = DecodeUnsignedLeb128P1(&stream);
841        }
842
843        // Emit what was previously there, if anything
844        if (need_locals) {
845          InvokeLocalCbIfLive(context, reg, address, local_in_reg, local_cb);
846
847          local_in_reg[reg].name_ = StringDataByIdx(name_idx);
848          local_in_reg[reg].descriptor_ = StringByTypeIdx(descriptor_idx);
849          if (opcode == DBG_START_LOCAL_EXTENDED) {
850            local_in_reg[reg].signature_ = StringDataByIdx(signature_idx);
851          }
852          local_in_reg[reg].start_address_ = address;
853          local_in_reg[reg].is_live_ = true;
854        }
855        break;
856
857      case DBG_END_LOCAL:
858        reg = DecodeUnsignedLeb128(&stream);
859        if (reg > code_item->registers_size_) {
860          LOG(ERROR) << "invalid stream - reg > reg size (" << reg << " > "
861                     << code_item->registers_size_ << ") in " << GetLocation();
862          return;
863        }
864
865        if (need_locals) {
866          InvokeLocalCbIfLive(context, reg, address, local_in_reg, local_cb);
867          local_in_reg[reg].is_live_ = false;
868        }
869        break;
870
871      case DBG_RESTART_LOCAL:
872        reg = DecodeUnsignedLeb128(&stream);
873        if (reg > code_item->registers_size_) {
874          LOG(ERROR) << "invalid stream - reg > reg size (" << reg << " > "
875                     << code_item->registers_size_ << ") in " << GetLocation();
876          return;
877        }
878
879        if (need_locals) {
880          if (local_in_reg[reg].name_ == NULL || local_in_reg[reg].descriptor_ == NULL) {
881            LOG(ERROR) << "invalid stream - no name or descriptor in " << GetLocation();
882            return;
883          }
884
885          // If the register is live, the "restart" is superfluous,
886          // and we don't want to mess with the existing start address.
887          if (!local_in_reg[reg].is_live_) {
888            local_in_reg[reg].start_address_ = address;
889            local_in_reg[reg].is_live_ = true;
890          }
891        }
892        break;
893
894      case DBG_SET_PROLOGUE_END:
895      case DBG_SET_EPILOGUE_BEGIN:
896      case DBG_SET_FILE:
897        break;
898
899      default: {
900        int adjopcode = opcode - DBG_FIRST_SPECIAL;
901
902        address += adjopcode / DBG_LINE_RANGE;
903        line += DBG_LINE_BASE + (adjopcode % DBG_LINE_RANGE);
904
905        if (position_cb != NULL) {
906          if (position_cb(context, address, line)) {
907            // early exit
908            return;
909          }
910        }
911        break;
912      }
913    }
914  }
915}
916
917void DexFile::DecodeDebugInfo(const CodeItem* code_item, bool is_static, uint32_t method_idx,
918                              DexDebugNewPositionCb position_cb, DexDebugNewLocalCb local_cb,
919                              void* context) const {
920  DCHECK(code_item != nullptr);
921  const byte* stream = GetDebugInfoStream(code_item);
922  std::unique_ptr<LocalInfo[]> local_in_reg(local_cb != NULL ?
923                                      new LocalInfo[code_item->registers_size_] :
924                                      NULL);
925  if (stream != NULL) {
926    DecodeDebugInfo0(code_item, is_static, method_idx, position_cb, local_cb, context, stream, &local_in_reg[0]);
927  }
928  for (int reg = 0; reg < code_item->registers_size_; reg++) {
929    InvokeLocalCbIfLive(context, reg, code_item->insns_size_in_code_units_, &local_in_reg[0], local_cb);
930  }
931}
932
933bool DexFile::LineNumForPcCb(void* raw_context, uint32_t address, uint32_t line_num) {
934  LineNumFromPcContext* context = reinterpret_cast<LineNumFromPcContext*>(raw_context);
935
936  // We know that this callback will be called in
937  // ascending address order, so keep going until we find
938  // a match or we've just gone past it.
939  if (address > context->address_) {
940    // The line number from the previous positions callback
941    // wil be the final result.
942    return true;
943  } else {
944    context->line_num_ = line_num;
945    return address == context->address_;
946  }
947}
948
949bool DexFile::IsMultiDexLocation(const char* location) {
950  return strrchr(location, kMultiDexSeparator) != nullptr;
951}
952
953std::string DexFile::GetMultiDexClassesDexName(size_t number, const char* dex_location) {
954  if (number == 0) {
955    return dex_location;
956  } else {
957    return StringPrintf("%s" kMultiDexSeparatorString "classes%zu.dex", dex_location, number + 1);
958  }
959}
960
961std::string DexFile::GetDexCanonicalLocation(const char* dex_location) {
962  CHECK_NE(dex_location, static_cast<const char*>(nullptr));
963  std::string base_location = GetBaseLocation(dex_location);
964  const char* suffix = dex_location + base_location.size();
965  DCHECK(suffix[0] == 0 || suffix[0] == kMultiDexSeparator);
966  UniqueCPtr<const char[]> path(realpath(base_location.c_str(), nullptr));
967  if (path != nullptr && path.get() != base_location) {
968    return std::string(path.get()) + suffix;
969  } else if (suffix[0] == 0) {
970    return base_location;
971  } else {
972    return dex_location;
973  }
974}
975
976std::ostream& operator<<(std::ostream& os, const DexFile& dex_file) {
977  os << StringPrintf("[DexFile: %s dex-checksum=%08x location-checksum=%08x %p-%p]",
978                     dex_file.GetLocation().c_str(),
979                     dex_file.GetHeader().checksum_, dex_file.GetLocationChecksum(),
980                     dex_file.Begin(), dex_file.Begin() + dex_file.Size());
981  return os;
982}
983
984std::string Signature::ToString() const {
985  if (dex_file_ == nullptr) {
986    CHECK(proto_id_ == nullptr);
987    return "<no signature>";
988  }
989  const DexFile::TypeList* params = dex_file_->GetProtoParameters(*proto_id_);
990  std::string result;
991  if (params == nullptr) {
992    result += "()";
993  } else {
994    result += "(";
995    for (uint32_t i = 0; i < params->Size(); ++i) {
996      result += dex_file_->StringByTypeIdx(params->GetTypeItem(i).type_idx_);
997    }
998    result += ")";
999  }
1000  result += dex_file_->StringByTypeIdx(proto_id_->return_type_idx_);
1001  return result;
1002}
1003
1004bool Signature::operator==(const StringPiece& rhs) const {
1005  if (dex_file_ == nullptr) {
1006    return false;
1007  }
1008  StringPiece tail(rhs);
1009  if (!tail.starts_with("(")) {
1010    return false;  // Invalid signature
1011  }
1012  tail.remove_prefix(1);  // "(";
1013  const DexFile::TypeList* params = dex_file_->GetProtoParameters(*proto_id_);
1014  if (params != nullptr) {
1015    for (uint32_t i = 0; i < params->Size(); ++i) {
1016      StringPiece param(dex_file_->StringByTypeIdx(params->GetTypeItem(i).type_idx_));
1017      if (!tail.starts_with(param)) {
1018        return false;
1019      }
1020      tail.remove_prefix(param.length());
1021    }
1022  }
1023  if (!tail.starts_with(")")) {
1024    return false;
1025  }
1026  tail.remove_prefix(1);  // ")";
1027  return tail == dex_file_->StringByTypeIdx(proto_id_->return_type_idx_);
1028}
1029
1030std::ostream& operator<<(std::ostream& os, const Signature& sig) {
1031  return os << sig.ToString();
1032}
1033
1034// Decodes the header section from the class data bytes.
1035void ClassDataItemIterator::ReadClassDataHeader() {
1036  CHECK(ptr_pos_ != NULL);
1037  header_.static_fields_size_ = DecodeUnsignedLeb128(&ptr_pos_);
1038  header_.instance_fields_size_ = DecodeUnsignedLeb128(&ptr_pos_);
1039  header_.direct_methods_size_ = DecodeUnsignedLeb128(&ptr_pos_);
1040  header_.virtual_methods_size_ = DecodeUnsignedLeb128(&ptr_pos_);
1041}
1042
1043void ClassDataItemIterator::ReadClassDataField() {
1044  field_.field_idx_delta_ = DecodeUnsignedLeb128(&ptr_pos_);
1045  field_.access_flags_ = DecodeUnsignedLeb128(&ptr_pos_);
1046  if (last_idx_ != 0 && field_.field_idx_delta_ == 0) {
1047    LOG(WARNING) << "Duplicate field in " << dex_file_.GetLocation();
1048  }
1049}
1050
1051void ClassDataItemIterator::ReadClassDataMethod() {
1052  method_.method_idx_delta_ = DecodeUnsignedLeb128(&ptr_pos_);
1053  method_.access_flags_ = DecodeUnsignedLeb128(&ptr_pos_);
1054  method_.code_off_ = DecodeUnsignedLeb128(&ptr_pos_);
1055  if (last_idx_ != 0 && method_.method_idx_delta_ == 0) {
1056    LOG(WARNING) << "Duplicate method in " << dex_file_.GetLocation();
1057  }
1058}
1059
1060// Read a signed integer.  "zwidth" is the zero-based byte count.
1061static int32_t ReadSignedInt(const byte* ptr, int zwidth) {
1062  int32_t val = 0;
1063  for (int i = zwidth; i >= 0; --i) {
1064    val = ((uint32_t)val >> 8) | (((int32_t)*ptr++) << 24);
1065  }
1066  val >>= (3 - zwidth) * 8;
1067  return val;
1068}
1069
1070// Read an unsigned integer.  "zwidth" is the zero-based byte count,
1071// "fill_on_right" indicates which side we want to zero-fill from.
1072static uint32_t ReadUnsignedInt(const byte* ptr, int zwidth, bool fill_on_right) {
1073  uint32_t val = 0;
1074  if (!fill_on_right) {
1075    for (int i = zwidth; i >= 0; --i) {
1076      val = (val >> 8) | (((uint32_t)*ptr++) << 24);
1077    }
1078    val >>= (3 - zwidth) * 8;
1079  } else {
1080    for (int i = zwidth; i >= 0; --i) {
1081      val = (val >> 8) | (((uint32_t)*ptr++) << 24);
1082    }
1083  }
1084  return val;
1085}
1086
1087// Read a signed long.  "zwidth" is the zero-based byte count.
1088static int64_t ReadSignedLong(const byte* ptr, int zwidth) {
1089  int64_t val = 0;
1090  for (int i = zwidth; i >= 0; --i) {
1091    val = ((uint64_t)val >> 8) | (((int64_t)*ptr++) << 56);
1092  }
1093  val >>= (7 - zwidth) * 8;
1094  return val;
1095}
1096
1097// Read an unsigned long.  "zwidth" is the zero-based byte count,
1098// "fill_on_right" indicates which side we want to zero-fill from.
1099static uint64_t ReadUnsignedLong(const byte* ptr, int zwidth, bool fill_on_right) {
1100  uint64_t val = 0;
1101  if (!fill_on_right) {
1102    for (int i = zwidth; i >= 0; --i) {
1103      val = (val >> 8) | (((uint64_t)*ptr++) << 56);
1104    }
1105    val >>= (7 - zwidth) * 8;
1106  } else {
1107    for (int i = zwidth; i >= 0; --i) {
1108      val = (val >> 8) | (((uint64_t)*ptr++) << 56);
1109    }
1110  }
1111  return val;
1112}
1113
1114EncodedStaticFieldValueIterator::EncodedStaticFieldValueIterator(const DexFile& dex_file,
1115                                                                 Handle<mirror::DexCache>* dex_cache,
1116                                                                 Handle<mirror::ClassLoader>* class_loader,
1117                                                                 ClassLinker* linker,
1118                                                                 const DexFile::ClassDef& class_def)
1119    : dex_file_(dex_file), dex_cache_(dex_cache), class_loader_(class_loader), linker_(linker),
1120      array_size_(), pos_(-1), type_(kByte) {
1121  DCHECK(dex_cache != nullptr);
1122  DCHECK(class_loader != nullptr);
1123  ptr_ = dex_file.GetEncodedStaticFieldValuesArray(class_def);
1124  if (ptr_ == NULL) {
1125    array_size_ = 0;
1126  } else {
1127    array_size_ = DecodeUnsignedLeb128(&ptr_);
1128  }
1129  if (array_size_ > 0) {
1130    Next();
1131  }
1132}
1133
1134void EncodedStaticFieldValueIterator::Next() {
1135  pos_++;
1136  if (pos_ >= array_size_) {
1137    return;
1138  }
1139  byte value_type = *ptr_++;
1140  byte value_arg = value_type >> kEncodedValueArgShift;
1141  size_t width = value_arg + 1;  // assume and correct later
1142  type_ = static_cast<ValueType>(value_type & kEncodedValueTypeMask);
1143  switch (type_) {
1144  case kBoolean:
1145    jval_.i = (value_arg != 0) ? 1 : 0;
1146    width = 0;
1147    break;
1148  case kByte:
1149    jval_.i = ReadSignedInt(ptr_, value_arg);
1150    CHECK(IsInt(8, jval_.i));
1151    break;
1152  case kShort:
1153    jval_.i = ReadSignedInt(ptr_, value_arg);
1154    CHECK(IsInt(16, jval_.i));
1155    break;
1156  case kChar:
1157    jval_.i = ReadUnsignedInt(ptr_, value_arg, false);
1158    CHECK(IsUint(16, jval_.i));
1159    break;
1160  case kInt:
1161    jval_.i = ReadSignedInt(ptr_, value_arg);
1162    break;
1163  case kLong:
1164    jval_.j = ReadSignedLong(ptr_, value_arg);
1165    break;
1166  case kFloat:
1167    jval_.i = ReadUnsignedInt(ptr_, value_arg, true);
1168    break;
1169  case kDouble:
1170    jval_.j = ReadUnsignedLong(ptr_, value_arg, true);
1171    break;
1172  case kString:
1173  case kType:
1174    jval_.i = ReadUnsignedInt(ptr_, value_arg, false);
1175    break;
1176  case kField:
1177  case kMethod:
1178  case kEnum:
1179  case kArray:
1180  case kAnnotation:
1181    UNIMPLEMENTED(FATAL) << ": type " << type_;
1182    break;
1183  case kNull:
1184    jval_.l = NULL;
1185    width = 0;
1186    break;
1187  default:
1188    LOG(FATAL) << "Unreached";
1189  }
1190  ptr_ += width;
1191}
1192
1193template<bool kTransactionActive>
1194void EncodedStaticFieldValueIterator::ReadValueToField(mirror::ArtField* field) const {
1195  switch (type_) {
1196    case kBoolean: field->SetBoolean<kTransactionActive>(field->GetDeclaringClass(), jval_.z); break;
1197    case kByte:    field->SetByte<kTransactionActive>(field->GetDeclaringClass(), jval_.b); break;
1198    case kShort:   field->SetShort<kTransactionActive>(field->GetDeclaringClass(), jval_.s); break;
1199    case kChar:    field->SetChar<kTransactionActive>(field->GetDeclaringClass(), jval_.c); break;
1200    case kInt:     field->SetInt<kTransactionActive>(field->GetDeclaringClass(), jval_.i); break;
1201    case kLong:    field->SetLong<kTransactionActive>(field->GetDeclaringClass(), jval_.j); break;
1202    case kFloat:   field->SetFloat<kTransactionActive>(field->GetDeclaringClass(), jval_.f); break;
1203    case kDouble:  field->SetDouble<kTransactionActive>(field->GetDeclaringClass(), jval_.d); break;
1204    case kNull:    field->SetObject<kTransactionActive>(field->GetDeclaringClass(), NULL); break;
1205    case kString: {
1206      CHECK(!kMovingFields);
1207      mirror::String* resolved = linker_->ResolveString(dex_file_, jval_.i, *dex_cache_);
1208      field->SetObject<kTransactionActive>(field->GetDeclaringClass(), resolved);
1209      break;
1210    }
1211    case kType: {
1212      CHECK(!kMovingFields);
1213      mirror::Class* resolved = linker_->ResolveType(dex_file_, jval_.i, *dex_cache_,
1214                                                     *class_loader_);
1215      field->SetObject<kTransactionActive>(field->GetDeclaringClass(), resolved);
1216      break;
1217    }
1218    default: UNIMPLEMENTED(FATAL) << ": type " << type_;
1219  }
1220}
1221template void EncodedStaticFieldValueIterator::ReadValueToField<true>(mirror::ArtField* field) const;
1222template void EncodedStaticFieldValueIterator::ReadValueToField<false>(mirror::ArtField* field) const;
1223
1224CatchHandlerIterator::CatchHandlerIterator(const DexFile::CodeItem& code_item, uint32_t address) {
1225  handler_.address_ = -1;
1226  int32_t offset = -1;
1227
1228  // Short-circuit the overwhelmingly common cases.
1229  switch (code_item.tries_size_) {
1230    case 0:
1231      break;
1232    case 1: {
1233      const DexFile::TryItem* tries = DexFile::GetTryItems(code_item, 0);
1234      uint32_t start = tries->start_addr_;
1235      if (address >= start) {
1236        uint32_t end = start + tries->insn_count_;
1237        if (address < end) {
1238          offset = tries->handler_off_;
1239        }
1240      }
1241      break;
1242    }
1243    default:
1244      offset = DexFile::FindCatchHandlerOffset(code_item, address);
1245  }
1246  Init(code_item, offset);
1247}
1248
1249CatchHandlerIterator::CatchHandlerIterator(const DexFile::CodeItem& code_item,
1250                                           const DexFile::TryItem& try_item) {
1251  handler_.address_ = -1;
1252  Init(code_item, try_item.handler_off_);
1253}
1254
1255void CatchHandlerIterator::Init(const DexFile::CodeItem& code_item,
1256                                int32_t offset) {
1257  if (offset >= 0) {
1258    Init(DexFile::GetCatchHandlerData(code_item, offset));
1259  } else {
1260    // Not found, initialize as empty
1261    current_data_ = NULL;
1262    remaining_count_ = -1;
1263    catch_all_ = false;
1264    DCHECK(!HasNext());
1265  }
1266}
1267
1268void CatchHandlerIterator::Init(const byte* handler_data) {
1269  current_data_ = handler_data;
1270  remaining_count_ = DecodeSignedLeb128(&current_data_);
1271
1272  // If remaining_count_ is non-positive, then it is the negative of
1273  // the number of catch types, and the catches are followed by a
1274  // catch-all handler.
1275  if (remaining_count_ <= 0) {
1276    catch_all_ = true;
1277    remaining_count_ = -remaining_count_;
1278  } else {
1279    catch_all_ = false;
1280  }
1281  Next();
1282}
1283
1284void CatchHandlerIterator::Next() {
1285  if (remaining_count_ > 0) {
1286    handler_.type_idx_ = DecodeUnsignedLeb128(&current_data_);
1287    handler_.address_  = DecodeUnsignedLeb128(&current_data_);
1288    remaining_count_--;
1289    return;
1290  }
1291
1292  if (catch_all_) {
1293    handler_.type_idx_ = DexFile::kDexNoIndex16;
1294    handler_.address_  = DecodeUnsignedLeb128(&current_data_);
1295    catch_all_ = false;
1296    return;
1297  }
1298
1299  // no more handler
1300  remaining_count_ = -1;
1301}
1302
1303}  // namespace art
1304