Use new NetworkTables across WPILib (C++ and Java).

Also make sure table listeners stop listening in their destructors.  This
might be better handled by moving the table itself into ITableListener and
providing cleanup functionality there.

A submodule is used to pull in ntcore.

Change-Id: I3031c1a768595cf0f8754c47e15cd423e2dbcce5

wpilibc/wpilibC++Devices/src/Preferences.cpp

@@ -15,25 +15,8 @@
 
 /** The Preferences table name */
 static const char *kTableName = "Preferences";
-/** The value of the save field */
-static const char *kSaveField = "~S A V E~";
-/** The file to save to */
-static const char *kFileName = "/home/lvuser/wpilib-preferences.ini";
-/** The characters to put between a field and value */
-static const char *kValuePrefix = "=\"";
-/** The characters to put after the value */
-static const char *kValueSuffix = "\"\n";
-
-Preferences::Preferences() {
-  std::unique_lock<priority_recursive_mutex> sync(m_fileLock);
-  m_readTask = Task("PreferencesReadTask", &Preferences::ReadTaskRun, this);
-
-  /* The main thread initially blocks on the semaphore. The read task signals
-   * the main thread to continue after it has locked the table mutex (so the
-   * table will be fully populated when the main thread can finally access it).
-   */
-  m_fileOpStarted.take();
 
+Preferences::Preferences() : m_table(NetworkTable::GetTable(kTableName)) {
   HALReport(HALUsageReporting::kResourceType_Preferences, 0);
 }
 
@@ -50,7 +33,7 @@ Preferences *Preferences::GetInstance() {
  * Returns a vector of all the keys
  * @return a vector of the keys
  */
-std::vector<std::string> Preferences::GetKeys() { return m_keys; }
+std::vector<std::string> Preferences::GetKeys() { return m_table->GetKeys(); }
 
 /**
  * Returns the string at the given key.  If this table does not have a value
@@ -59,25 +42,9 @@ std::vector<std::string> Preferences::GetKeys() { return m_keys; }
  * @param defaultValue the value to return if none exists in the table
  * @return either the value in the table, or the defaultValue
  */
-std::string Preferences::GetString(const char *key, const char *defaultValue) {
-  std::string value = Get(key);
-  return value.empty() ? defaultValue : value;
-}
-
-/**
- * Returns the string at the given key.  If this table does not have a value
- * for that position, then the given defaultValue will be returned.
- * @param key the key
- * @param value the buffer to copy the value into
- * @param valueSize the size of value
- * @param defaultValue the value to return if none exists in the table
- * @return The size of the returned string
- */
-int Preferences::GetString(const char *key, char *value, int valueSize,
-                           const char *defaultValue) {
-  std::string stringValue = GetString(key, defaultValue);
-  stringValue.copy(value, valueSize);
-  return stringValue.size();
+std::string Preferences::GetString(llvm::StringRef key,
+                                   llvm::StringRef defaultValue) {
+  return m_table->GetString(key, defaultValue);
 }
 
 /**
@@ -87,11 +54,8 @@ int Preferences::GetString(const char *key, char *value, int valueSize,
  * @param defaultValue the value to return if none exists in the table
  * @return either the value in the table, or the defaultValue
  */
-int Preferences::GetInt(const char *key, int defaultValue) {
-  std::string value = Get(key);
-  if (value.empty()) return defaultValue;
-
-  return strtol(value.c_str(), nullptr, 0);
+int Preferences::GetInt(llvm::StringRef key, int defaultValue) {
+  return static_cast<int>(m_table->GetNumber(key, defaultValue));
 }
 
 /**
@@ -101,11 +65,8 @@ int Preferences::GetInt(const char *key, int defaultValue) {
  * @param defaultValue the value to return if none exists in the table
  * @return either the value in the table, or the defaultValue
  */
-double Preferences::GetDouble(const char *key, double defaultValue) {
-  std::string value = Get(key);
-  if (value.empty()) return defaultValue;
-
-  return strtod(value.c_str(), nullptr);
+double Preferences::GetDouble(llvm::StringRef key, double defaultValue) {
+  return m_table->GetNumber(key, defaultValue);
 }
 
 /**
@@ -115,11 +76,8 @@ double Preferences::GetDouble(const char *key, double defaultValue) {
  * @param defaultValue the value to return if none exists in the table
  * @return either the value in the table, or the defaultValue
  */
-float Preferences::GetFloat(const char *key, float defaultValue) {
-  std::string value = Get(key);
-  if (value.empty()) return defaultValue;
-
-  return strtod(value.c_str(), nullptr);
+float Preferences::GetFloat(llvm::StringRef key, float defaultValue) {
+  return static_cast<float>(m_table->GetNumber(key, defaultValue));
 }
 
 /**
@@ -129,19 +87,8 @@ float Preferences::GetFloat(const char *key, float defaultValue) {
  * @param defaultValue the value to return if none exists in the table
  * @return either the value in the table, or the defaultValue
  */
-bool Preferences::GetBoolean(const char *key, bool defaultValue) {
-  std::string value = Get(key);
-  if (value.empty()) return defaultValue;
-
-  if (value.compare("true") == 0)
-    return true;
-  else if (value.compare("false") == 0)
-    return false;
-
-  wpi_setWPIErrorWithContext(
-      ParameterOutOfRange,
-      "Boolean value does not contain \"true\" or \"false\"");
-  return false;
+bool Preferences::GetBoolean(llvm::StringRef key, bool defaultValue) {
+  return m_table->GetBoolean(key, defaultValue);
 }
 
 /**
@@ -152,15 +99,8 @@ bool Preferences::GetBoolean(const char *key, bool defaultValue) {
  * @param defaultValue the value to return if none exists in the table
  * @return either the value in the table, or the defaultValue
  */
-int64_t Preferences::GetLong(const char *key, int64_t defaultValue) {
-  std::string value = Get(key);
-  if (value.empty()) return defaultValue;
-
-  // Ummm... not available in our VxWorks...
-  // return strtoll(value.c_str(), nullptr, 0);
-  int64_t intVal;
-  sscanf(value.c_str(), "%lld", &intVal);
-  return intVal;
+int64_t Preferences::GetLong(llvm::StringRef key, int64_t defaultValue) {
+  return static_cast<int64_t>(m_table->GetNumber(key, defaultValue));
 }
 
 /**
@@ -169,24 +109,12 @@ int64_t Preferences::GetLong(const char *key, int64_t defaultValue) {
  * <p>The value may not have quotation marks, nor may the key
  * have any whitespace nor an equals sign</p>
  *
- * <p>This will <b>NOT</b> save the value to memory between power cycles,
- * to do that you must call {@link Preferences#Save() Save()} (which must be
- * used with care).
- * at some point after calling this.</p>
  * @param key the key
  * @param value the value
  */
-void Preferences::PutString(const char *key, const char *value) {
-  if (value == nullptr) {
-    wpi_setWPIErrorWithContext(NullParameter, "value");
-    return;
-  }
-  if (std::string(value).find_first_of("\"") != std::string::npos) {
-    wpi_setWPIErrorWithContext(ParameterOutOfRange,
-                               "value contains illegal characters");
-    return;
-  }
-  Put(key, value);
+void Preferences::PutString(llvm::StringRef key, llvm::StringRef value) {
+  m_table->PutString(key, value);
+  m_table->SetPersistent(key);
 }
 
 /**
@@ -194,17 +122,12 @@ void Preferences::PutString(const char *key, const char *value) {
  *
  * <p>The key may not have any whitespace nor an equals sign</p>
  *
- * <p>This will <b>NOT</b> save the value to memory between power cycles,
- * to do that you must call {@link Preferences#Save() Save()} (which must be
- * used with care)
- * at some point after calling this.</p>
  * @param key the key
  * @param value the value
  */
-void Preferences::PutInt(const char *key, int value) {
-  char buf[32];
-  snprintf(buf, 32, "%d", value);
-  Put(key, buf);
+void Preferences::PutInt(llvm::StringRef key, int value) {
+  m_table->PutNumber(key, value);
+  m_table->SetPersistent(key);
 }
 
 /**
@@ -212,17 +135,12 @@ void Preferences::PutInt(const char *key, int value) {
  *
  * <p>The key may not have any whitespace nor an equals sign</p>
  *
- * <p>This will <b>NOT</b> save the value to memory between power cycles,
- * to do that you must call {@link Preferences#Save() Save()} (which must be
- * used with care)
- * at some point after calling this.</p>
  * @param key the key
  * @param value the value
  */
-void Preferences::PutDouble(const char *key, double value) {
-  char buf[32];
-  snprintf(buf, 32, "%f", value);
-  Put(key, buf);
+void Preferences::PutDouble(llvm::StringRef key, double value) {
+  m_table->PutNumber(key, value);
+  m_table->SetPersistent(key);
 }
 
 /**
@@ -230,17 +148,12 @@ void Preferences::PutDouble(const char *key, double value) {
  *
  * <p>The key may not have any whitespace nor an equals sign</p>
  *
- * <p>This will <b>NOT</b> save the value to memory between power cycles,
- * to do that you must call {@link Preferences#Save() Save()} (which must be
- * used with care)
- * at some point after calling this.</p>
  * @param key the key
  * @param value the value
  */
-void Preferences::PutFloat(const char *key, float value) {
-  char buf[32];
-  snprintf(buf, 32, "%f", value);
-  Put(key, buf);
+void Preferences::PutFloat(llvm::StringRef key, float value) {
+  m_table->PutNumber(key, value);
+  m_table->SetPersistent(key);
 }
 
 /**
@@ -248,15 +161,12 @@ void Preferences::PutFloat(const char *key, float value) {
  *
  * <p>The key may not have any whitespace nor an equals sign</p>
  *
- * <p>This will <b>NOT</b> save the value to memory between power cycles,
- * to do that you must call {@link Preferences#Save() Save()} (which must be
- * used with care)
- * at some point after calling this.</p>
  * @param key the key
  * @param value the value
  */
-void Preferences::PutBoolean(const char *key, bool value) {
-  Put(key, value ? "true" : "false");
+void Preferences::PutBoolean(llvm::StringRef key, bool value) {
+  m_table->PutBoolean(key, value);
+  m_table->SetPersistent(key);
 }
 
 /**
@@ -264,282 +174,35 @@ void Preferences::PutBoolean(const char *key, bool value) {
  *
  * <p>The key may not have any whitespace nor an equals sign</p>
  *
- * <p>This will <b>NOT</b> save the value to memory between power cycles,
- * to do that you must call {@link Preferences#Save() Save()} (which must be
- * used with care)
- * at some point after calling this.</p>
  * @param key the key
  * @param value the value
  */
-void Preferences::PutLong(const char *key, int64_t value) {
-  char buf[32];
-  snprintf(buf, 32, "%lld", value);
-  Put(key, buf);
+void Preferences::PutLong(llvm::StringRef key, int64_t value) {
+  m_table->PutNumber(key, value);
+  m_table->SetPersistent(key);
 }
 
 /**
- * Saves the preferences to a file on the RoboRIO.
- *
- * <p>This should <b>NOT</b> be called often.
- * Too many writes can damage the RoboRIO's flash memory.
- * While it is ok to save once or twice a match, this should never
- * be called every run of {@link IterativeRobot#TeleopPeriodic()}, etc.</p>
- *
- * <p>The actual writing of the file is done in a separate thread.
- * However, any call to a get or put method will wait until the table is fully
- * saved before continuing.</p>
+ * This function is no longer required, as NetworkTables automatically
+ * saves persistent values (which all Preferences values are) periodically
+ * when running as a server.
+ * @deprecated backwards compatibility shim
  */
-void Preferences::Save() {
-  std::unique_lock<priority_recursive_mutex> sync(m_fileLock);
-  m_writeTask = Task("PreferencesWriteTask", &Preferences::WriteTaskRun, this);
-  m_fileOpStarted.take();
-}
+void Preferences::Save() {}
 
 /**
  * Returns whether or not there is a key with the given name.
  * @param key the key
  * @return if there is a value at the given key
  */
-bool Preferences::ContainsKey(const char *key) { return !Get(key).empty(); }
+bool Preferences::ContainsKey(llvm::StringRef key) {
+  return m_table->ContainsKey(key);
+}
 
 /**
  * Remove a preference
  * @param key the key
  */
-void Preferences::Remove(const char *key) {
-  m_values.erase(std::string(key));
-  auto it = m_keys.begin();
-  for (; it != m_keys.end(); it++) {
-    if (it->compare(key) == 0) {
-      m_keys.erase(it);
-      break;
-    }
-  }
-}
-
-/**
- * Returns the value at the given key.
- * @param key the key
- * @return the value (or empty if none exists)
- */
-std::string Preferences::Get(const char *key) {
-  std::unique_lock<priority_recursive_mutex> sync(m_tableLock);
-  if (key == nullptr) {
-    wpi_setWPIErrorWithContext(NullParameter, "key");
-    return "";
-  }
-  return m_values[key];
-}
-
-/**
- * Puts the given value into the given key position
- * @param key the key
- * @param value the value
- */
-void Preferences::Put(const char *key, std::string value) {
-  std::unique_lock<priority_recursive_mutex> sync(m_tableLock);
-  if (key == nullptr) {
-    wpi_setWPIErrorWithContext(NullParameter, "key");
-    return;
-  }
-
-  if (std::string(key).find_first_of("=\n\r \t\"") != std::string::npos) {
-    wpi_setWPIErrorWithContext(ParameterOutOfRange,
-                               "key contains illegal characters");
-    return;
-  }
-
-  std::pair<StringMap::iterator, bool> ret =
-      m_values.insert(StringMap::value_type(key, value));
-  if (ret.second)
-    m_keys.push_back(key);
-  else
-    ret.first->second = value;
-
-  NetworkTable* table = NetworkTable::GetTable(kTableName);
-  table->PutString(key, value);
-}
-
-/**
- * The internal method to read from a file.
- * This will be called in its own thread when the preferences singleton is
- * first created.
- */
-void Preferences::ReadTaskRun() {
-  std::unique_lock<priority_recursive_mutex> sync(m_tableLock);
-  m_fileOpStarted.give();
-
-  std::string comment;
-
-  FILE *file = nullptr;
-  file = fopen(kFileName, "r");
-
-  if (file != nullptr) {
-    std::string buffer;
-    while (true) {
-      char value;
-      do {
-        value = fgetc(file);
-      } while (value == ' ' || value == '\t');
-
-      if (value == '\n' || value == ';') {
-        if (value == '\n') {
-          comment += "\n";
-        } else {
-          buffer.clear();
-          for (; value != '\n' && !feof(file); value = fgetc(file))
-            buffer += value;
-          buffer += '\n';
-          comment += buffer;
-        }
-      } else if (value == '[') {
-        // Find the end of the section and the new line after it and throw it
-        // away
-        for (; value != ']' && !feof(file); value = fgetc(file))
-          ;
-        for (; value != '\n' && !feof(file); value = fgetc(file))
-          ;
-      } else {
-        buffer.clear();
-        for (; value != '=' && !feof(file);) {
-          buffer += value;
-          do {
-            value = fgetc(file);
-          } while (value == ' ' || value == '\t');
-        }
-        std::string name = buffer;
-        buffer.clear();
-
-        bool shouldBreak = false;
-
-        do {
-          value = fgetc(file);
-        } while (value == ' ' || value == '\t');
-
-        if (value == '"') {
-          for (value = fgetc(file); value != '"' && !feof(file);
-               value = fgetc(file))
-            buffer += value;
-
-          // Clear the line
-          while (fgetc(file) != '\n' && !feof(file))
-            ;
-        } else {
-          for (; value != '\n' && !feof(file);) {
-            buffer += value;
-            do {
-              value = fgetc(file);
-            } while (value == ' ' || value == '\t');
-          }
-          if (feof(file)) shouldBreak = true;
-        }
-
-        std::string value = buffer;
-
-        if (!name.empty() && !value.empty()) {
-          m_keys.push_back(name);
-          m_values.insert(std::pair<std::string, std::string>(name, value));
-          NetworkTable::GetTable(kTableName)->PutString(name, value);
-
-          if (!comment.empty()) {
-            m_comments.insert(
-                std::pair<std::string, std::string>(name, comment));
-            comment.clear();
-          }
-        }
-
-        if (shouldBreak) break;
-      }
-    }
-  } else {
-    wpi_setErrnoErrorWithContext("Opening preferences file");
-  }
-
-  if (file != nullptr) fclose(file);
-
-  if (!comment.empty()) m_endComment = comment;
-
-  NetworkTable::GetTable(kTableName)->PutBoolean(kSaveField, false);
-  NetworkTable::GetTable(kTableName)->AddTableListener(this);
-}
-
-/**
- * Internal method that actually writes the table to a file.
- * This is called in its own thread when {@link Preferences#Save() Save()} is
- * called.
- */
-void Preferences::WriteTaskRun() {
-  std::unique_lock<priority_recursive_mutex> sync(m_tableLock);
-  m_fileOpStarted.give();
-
-  FILE *file = nullptr;
-  file = fopen(kFileName, "w");
-
-  fputs("[Preferences]\n", file);
-  auto it = m_keys.begin();
-  for (; it != m_keys.end(); it++) {
-    std::string key = *it;
-    std::string value = m_values[key];
-    std::string comment = m_comments[key];
-
-    if (!comment.empty()) fputs(comment.c_str(), file);
-
-    fputs(key.c_str(), file);
-    fputs(kValuePrefix, file);
-    fputs(value.c_str(), file);
-    fputs(kValueSuffix, file);
-  }
-
-  if (!m_endComment.empty()) fputs(m_endComment.c_str(), file);
-
-  if (file != nullptr) fclose(file);
-
-  NetworkTable::GetTable(kTableName)->PutBoolean(kSaveField, false);
-}
-
-static bool isKeyAcceptable(const std::string &value) {
-  for (auto letter : value) {
-    switch (letter) {
-      case '=':
-      case '\n':
-      case '\r':
-      case ' ':
-      case '\t':
-      case '[':
-      case ']':
-        return false;
-    }
-  }
-  return true;
-}
-
-void Preferences::ValueChanged(std::shared_ptr<ITable> table, const std::string &key,
-                               EntryValue value, bool isNew) {
-  if (key == kSaveField) {
-    if (table->GetBoolean(kSaveField, false)) Save();
-  } else {
-    std::unique_lock<priority_recursive_mutex> sync(m_tableLock);
-
-    if (!isKeyAcceptable(key) ||
-        table->GetString(key, "").find('"') != std::string::npos) {
-      if (m_values.find(key) != m_values.end()) {
-        m_values.erase(key);
-        auto it = m_keys.begin();
-        for (; it != m_keys.end(); it++) {
-          if (key == *it) {
-            m_keys.erase(it);
-            break;
-          }
-        }
-        table->PutString(key, "\"");
-      }
-    } else {
-      std::pair<StringMap::iterator, bool> ret = m_values.insert(
-          StringMap::value_type(key, table->GetString(key, "")));
-      if (ret.second)
-        m_keys.push_back(key);
-      else
-        ret.first->second = table->GetString(key, "");
-    }
-  }
+void Preferences::Remove(llvm::StringRef key) {
+  m_table->Delete(key);
 }