Use a class instead of several separate globals in crash_logging.cc.

base/debug/crash_logging.cc

Index: base/debug/crash_logging.cc
diff --git a/base/debug/crash_logging.cc b/base/debug/crash_logging.cc
index 058b476800da3a65bd35f3b6cb2f804533986e26..63ef7f38cc0cce885c12cd00b363c5f6742b7cc7 100644
--- a/base/debug/crash_logging.cc
+++ b/base/debug/crash_logging.cc
@@ -4,12 +4,12 @@
 
 #include "base/debug/crash_logging.h"
 
-#include <cmath>
 #include <map>
 
 #include "base/debug/stack_trace.h"
 #include "base/format_macros.h"
 #include "base/logging.h"
+#include "base/memory/singleton.h"
 #include "base/strings/string_util.h"
 #include "base/strings/stringprintf.h"
 
@@ -18,79 +18,158 @@ namespace debug {
 
 namespace {
 
-// Global map of crash key names to registration entries.
-typedef std::map<base::StringPiece, CrashKey> CrashKeyMap;
-CrashKeyMap* g_crash_keys_ = NULL;
-
-// The maximum length of a single chunk.
-size_t g_chunk_max_length_ = 0;
-
 // String used to format chunked key names.
 const char kChunkFormatString[] = "%s-%" PRIuS;
 
-// The functions that are called to actually set the key-value pairs in the
-// crash reportng system.
-SetCrashKeyValueFuncT g_set_key_func_ = NULL;
-ClearCrashKeyValueFuncT g_clear_key_func_ = NULL;
-
-// For a given |length|, computes the number of chunks a value of that size
-// will occupy.
-size_t NumChunksForLength(size_t length) {
-  // Compute (length / g_chunk_max_length_), rounded up.
-  return (length + g_chunk_max_length_ - 1) / g_chunk_max_length_;
-}
-
 // The longest max_length allowed by the system.
 const size_t kLargestValueAllowed = 1024;
 
+// The CrashKeyRegistry is a singleton that holds the global state of the crash
+// key logging system.
+class CrashKeyRegistry {
+ public:
+  static CrashKeyRegistry* GetInstance() {
+    return Singleton<CrashKeyRegistry>::get();
+  }
+
+  // Initializes the set of allowed crash keys.
+  size_t Init(const CrashKey* const keys, size_t count,
+              size_t chunk_max_length) {
+    DCHECK(!initialized_) << "Crash logging may only be initialized once";
+
+    chunk_max_length_ = chunk_max_length;
+
+    size_t total_keys = 0;
+    for (size_t i = 0; i < count; ++i) {
+      crash_keys_.insert(std::make_pair(keys[i].key_name, keys[i]));
+      total_keys += NumChunksForLength(keys[i].max_length);
+      DCHECK_LT(keys[i].max_length, kLargestValueAllowed);
+    }
+
+    DCHECK_EQ(count, crash_keys_.size())
+        << "Duplicate crash keys were registered";
+    initialized_ = true;
+
+    return total_keys;
+  }
+
+  // Sets the function pointers to integrate with the platform-specific crash
+  // reporting system.
+  void SetFunctions(SetCrashKeyValueFuncT set_key_func,
+                    ClearCrashKeyValueFuncT clear_key_func) {
+    set_key_func_ = set_key_func;
+    clear_key_func_ = clear_key_func;
+  }
+
+  // Looks up the CrashKey object by key.
+  const CrashKey* LookupCrashKey(const base::StringPiece& key) {
+    CrashKeyMap::const_iterator it = crash_keys_.find(key.as_string());
+    if (it == crash_keys_.end())
+      return nullptr;
+    return &(it->second);
+  }
+
+  // For a given |length|, computes the number of chunks a value of that size
+  // will occupy.
+  size_t NumChunksForLength(size_t length) const {
+    // Compute (length / g_chunk_max_length_), rounded up.
+    return (length + chunk_max_length_ - 1) / chunk_max_length_;
+  }
+
+  void SetKeyValue(const base::StringPiece& key,
+                   const base::StringPiece& value) {
+    set_key_func_(key, value);
+  }
+
+  void ClearKey(const base::StringPiece& key) {
+    clear_key_func_(key);
+  }
+
+  bool is_initialized() const { return initialized_ && set_key_func_; }
+
+  size_t chunk_max_length() const { return chunk_max_length_; }
+
+ private:
+  friend struct DefaultSingletonTraits<CrashKeyRegistry>;
+
+  CrashKeyRegistry()
+      : initialized_(false),
+        chunk_max_length_(0),
+        set_key_func_(nullptr),
+        clear_key_func_(nullptr) {
+  }
+
+  ~CrashKeyRegistry() {}
+
+  bool initialized_;
+
+  // Map of crash key names to registration entries.
+  using CrashKeyMap = std::map<base::StringPiece, CrashKey>;
+  CrashKeyMap crash_keys_;
+
+  size_t chunk_max_length_;
+
+  // The functions that are called to actually set the key-value pairs in the
+  // crash reportng system.
+  SetCrashKeyValueFuncT set_key_func_;
+  ClearCrashKeyValueFuncT clear_key_func_;
+
+  DISALLOW_COPY_AND_ASSIGN(CrashKeyRegistry);
+};
+
 }  // namespace
 
 void SetCrashKeyValue(const base::StringPiece& key,
                       const base::StringPiece& value) {
-  if (!g_set_key_func_ || !g_crash_keys_)
+  CrashKeyRegistry* registry = CrashKeyRegistry::GetInstance();
+  if (!registry->is_initialized())
     return;
 
-  const CrashKey* crash_key = LookupCrashKey(key);
+  const CrashKey* crash_key = registry->LookupCrashKey(key);
 
   DCHECK(crash_key) << "All crash keys must be registered before use "
                     << "(key = " << key << ")";
 
   // Handle the un-chunked case.
-  if (!crash_key || crash_key->max_length <= g_chunk_max_length_) {
-    g_set_key_func_(key, value);
+  if (!crash_key || crash_key->max_length <= registry->chunk_max_length()) {
+    registry->SetKeyValue(key, value);
     return;
   }
 
   // Unset the unused chunks.
   std::vector<std::string> chunks =
-      ChunkCrashKeyValue(*crash_key, value, g_chunk_max_length_);
+      ChunkCrashKeyValue(*crash_key, value, registry->chunk_max_length());
   for (size_t i = chunks.size();
-       i < NumChunksForLength(crash_key->max_length);
+       i < registry->NumChunksForLength(crash_key->max_length);
        ++i) {
-    g_clear_key_func_(base::StringPrintf(kChunkFormatString, key.data(), i+1));
+    registry->ClearKey(base::StringPrintf(kChunkFormatString, key.data(), i+1));
   }
 
   // Set the chunked keys.
   for (size_t i = 0; i < chunks.size(); ++i) {
-    g_set_key_func_(base::StringPrintf(kChunkFormatString, key.data(), i+1),
-                    chunks[i]);
+    registry->SetKeyValue(
+        base::StringPrintf(kChunkFormatString, key.data(), i+1),
+        chunks[i]);
   }
 }
 
 void ClearCrashKey(const base::StringPiece& key) {
-  if (!g_clear_key_func_ || !g_crash_keys_)
+  CrashKeyRegistry* registry = CrashKeyRegistry::GetInstance();
+  if (!registry->is_initialized())
     return;
 
-  const CrashKey* crash_key = LookupCrashKey(key);
+  const CrashKey* crash_key = registry->LookupCrashKey(key);
 
   // Handle the un-chunked case.
-  if (!crash_key || crash_key->max_length <= g_chunk_max_length_) {
-    g_clear_key_func_(key);
+  if (!crash_key || crash_key->max_length <= registry->chunk_max_length()) {
+    registry->ClearKey(key);
     return;
   }
 
-  for (size_t i = 0; i < NumChunksForLength(crash_key->max_length); ++i) {
-    g_clear_key_func_(base::StringPrintf(kChunkFormatString, key.data(), i+1));
+  for (size_t i = 0;
+       i < registry->NumChunksForLength(crash_key->max_length);
+       ++i) {
+    registry->ClearKey(base::StringPrintf(kChunkFormatString, key.data(), i+1));
   }
 }
 
@@ -140,42 +219,17 @@ ScopedCrashKey::~ScopedCrashKey() {
 
 size_t InitCrashKeys(const CrashKey* const keys, size_t count,
                      size_t chunk_max_length) {
-  DCHECK(!g_crash_keys_) << "Crash logging may only be initialized once";
-  if (!keys) {
-    delete g_crash_keys_;
-    g_crash_keys_ = NULL;
-    return 0;
-  }
-
-  g_crash_keys_ = new CrashKeyMap;
-  g_chunk_max_length_ = chunk_max_length;
-
-  size_t total_keys = 0;
-  for (size_t i = 0; i < count; ++i) {
-    g_crash_keys_->insert(std::make_pair(keys[i].key_name, keys[i]));
-    total_keys += NumChunksForLength(keys[i].max_length);
-    DCHECK_LT(keys[i].max_length, kLargestValueAllowed);
-  }
-  DCHECK_EQ(count, g_crash_keys_->size())
-      << "Duplicate crash keys were registered";
-
-  return total_keys;
+  return CrashKeyRegistry::GetInstance()->Init(keys, count, chunk_max_length);
 }
 
 const CrashKey* LookupCrashKey(const base::StringPiece& key) {
-  if (!g_crash_keys_)
-    return NULL;
-  CrashKeyMap::const_iterator it = g_crash_keys_->find(key.as_string());
-  if (it == g_crash_keys_->end())
-    return NULL;
-  return &(it->second);
+  return CrashKeyRegistry::GetInstance()->LookupCrashKey(key);
 }
 
 void SetCrashKeyReportingFunctions(
     SetCrashKeyValueFuncT set_key_func,
     ClearCrashKeyValueFuncT clear_key_func) {
-  g_set_key_func_ = set_key_func;
-  g_clear_key_func_ = clear_key_func;
+  CrashKeyRegistry::GetInstance()->SetFunctions(set_key_func, clear_key_func);
 }
 
 std::vector<std::string> ChunkCrashKeyValue(const CrashKey& crash_key,
@@ -191,13 +245,5 @@ std::vector<std::string> ChunkCrashKeyValue(const CrashKey& crash_key,
   return chunks;
 }
 
-void ResetCrashLoggingForTesting() {
-  delete g_crash_keys_;
-  g_crash_keys_ = NULL;
-  g_chunk_max_length_ = 0;
-  g_set_key_func_ = NULL;
-  g_clear_key_func_ = NULL;
-}
-
 }  // namespace debug
 }  // namespace base