/// <summary>Tries to get the value of a switch. </summary>
/// <param name="switchName">The name of the switch. </param>
/// <param name="isEnabled">When this method returns, contains the value of <paramref name="switchName" /> if <paramref name="switchName" /> was found, or <see langword="false" /> if <paramref name="switchName" /> was not found. This parameter is passed uninitialized. </param>
/// <returns>
/// <see langword="true" /> if <paramref name="switchName" /> was set and the <paramref name="isEnabled" /> argument contains the value of the switch; otherwise, <see langword="false" />. </returns>
/// <exception cref="T:System.ArgumentNullException">
/// <paramref name="switchName" /> is <see langword="null" />. </exception>
/// <exception cref="T:System.ArgumentException">
/// <paramref name="switchName" /> is <see cref="F:System.String.Empty" />. </exception>
// Token: 0x06000205 RID: 517 RVA: 0x00005304 File Offset: 0x00003504
public static bool TryGetSwitch(string switchName, out bool isEnabled)
{
if (switchName == null)
{
throw new ArgumentNullException("switchName");
}
if (switchName.Length == 0)
{
throw new ArgumentException(Environment.GetResourceString("Argument_EmptyName"), "switchName");
}
if (!AppContext.s_defaultsInitialized)
{
AppContext.InitializeDefaultSwitchValues();
}
isEnabled = false;
Dictionary <string, AppContext.SwitchValueState> obj = AppContext.s_switchMap;
lock (obj)
{
AppContext.SwitchValueState switchValueState;
if (AppContext.s_switchMap.TryGetValue(switchName, out switchValueState))
{
if (switchValueState == AppContext.SwitchValueState.UnknownValue)
{
isEnabled = false;
return(false);
}
isEnabled = ((switchValueState & AppContext.SwitchValueState.HasTrueValue) == AppContext.SwitchValueState.HasTrueValue);
if ((switchValueState & AppContext.SwitchValueState.HasLookedForOverride) == AppContext.SwitchValueState.HasLookedForOverride)
{
return(true);
}
bool flag2;
if (AppContextDefaultValues.TryGetSwitchOverride(switchName, out flag2))
{
isEnabled = flag2;
}
AppContext.s_switchMap[switchName] = ((isEnabled ? AppContext.SwitchValueState.HasTrueValue : AppContext.SwitchValueState.HasFalseValue) | AppContext.SwitchValueState.HasLookedForOverride);
return(true);
}
else
{
bool flag3;
if (AppContextDefaultValues.TryGetSwitchOverride(switchName, out flag3))
{
isEnabled = flag3;
AppContext.s_switchMap[switchName] = ((isEnabled ? AppContext.SwitchValueState.HasTrueValue : AppContext.SwitchValueState.HasFalseValue) | AppContext.SwitchValueState.HasLookedForOverride);
return(true);
}
AppContext.s_switchMap[switchName] = AppContext.SwitchValueState.UnknownValue;
}
}
return(false);
}
/// <summary>Trues 来获取一个开关的值。</summary>
/// <returns>true如果<paramref name="switchName" />设置和<paramref name="isEnabled" />参数中包含的开关 ； 值否则为false。</returns>
/// <param name="switchName">开关的名称。</param>
/// <param name="isEnabled">此方法返回时，包含值的<paramref name="switchName" />如果<paramref name="switchName" />找，或false如果<paramref name="switchName" />找不到。此参数未经初始化即被传递。</param>
/// <exception cref="T:System.ArgumentNullException">
/// <paramref name="switchName" /> 为 null。</exception>
/// <exception cref="T:System.ArgumentException">
/// <paramref name="switchName" /> 为 <see cref="F:System.String.Empty" />。</exception>
public static bool TryGetSwitch(string switchName, out bool isEnabled)
{
if (switchName == null)
{
throw new ArgumentNullException("switchName");
}
if (switchName.Length == 0)
{
throw new ArgumentException(Environment.GetResourceString("Argument_EmptyName"), "switchName");
}
isEnabled = false;
lock (AppContext.s_switchMap)
{
AppContext.SwitchValueState local_0;
if (AppContext.s_switchMap.TryGetValue(switchName, out local_0))
{
if (local_0 == AppContext.SwitchValueState.UnknownValue)
{
isEnabled = false;
return(false);
}
isEnabled = (local_0 & AppContext.SwitchValueState.HasTrueValue) == AppContext.SwitchValueState.HasTrueValue;
if ((local_0 & AppContext.SwitchValueState.HasLookedForOverride) == AppContext.SwitchValueState.HasLookedForOverride)
{
return(true);
}
bool local_3;
if (AppContextDefaultValues.TryGetSwitchOverride(switchName, out local_3))
{
isEnabled = local_3;
}
AppContext.s_switchMap[switchName] = (AppContext.SwitchValueState)((isEnabled ? 2 : 1) | 4);
return(true);
}
bool local_5;
if (AppContextDefaultValues.TryGetSwitchOverride(switchName, out local_5))
{
isEnabled = local_5;
AppContext.s_switchMap[switchName] = (AppContext.SwitchValueState)((isEnabled ? 2 : 1) | 4);
return(true);
}
AppContext.s_switchMap[switchName] = AppContext.SwitchValueState.UnknownValue;
}
return(false);
}
/// <summary>
/// Try to get the value of the switch.
/// </summary>
/// <param name="switchName">The name of the switch</param>
/// <param name="isEnabled">A variable where to place the value of the switch</param>
/// <returns>A return value of true represents that the switch was set and <paramref name="isEnabled"/> contains the value of the switch</returns>
public static bool TryGetSwitch(string switchName, out bool isEnabled)
{
if (switchName == null)
{
throw new ArgumentNullException(nameof(switchName));
}
if (switchName.Length == 0)
{
throw new ArgumentException(SR.Argument_EmptyName, nameof(switchName));
}
// By default, the switch is not enabled.
isEnabled = false;
SwitchValueState switchValue;
lock (s_switchMap)
{
if (s_switchMap.TryGetValue(switchName, out switchValue))
{
// The value is in the dictionary.
// There are 3 cases here:
// 1. The value of the switch is 'unknown'. This means that the switch name is not known to the system (either via defaults or checking overrides).
// Example: This is the case when, during a servicing event, a switch is added to System.Xml which ships before mscorlib. The value of the switch
// Will be unknown to mscorlib.dll and we want to prevent checking the overrides every time we check this switch
// 2. The switch has a valid value AND we have read the overrides for it
// Example: TryGetSwitch is called for a switch set via SetSwitch
// 3. The switch has the default value and we need to check for overrides
// Example: TryGetSwitch is called for the first time for a switch that has a default value
// 1. The value is unknown
if (switchValue == SwitchValueState.UnknownValue)
{
isEnabled = false;
return(false);
}
// We get the value of isEnabled from the value that we stored in the dictionary
isEnabled = (switchValue & SwitchValueState.HasTrueValue) == SwitchValueState.HasTrueValue;
// 2. The switch has a valid value AND we have checked for overrides
if ((switchValue & SwitchValueState.HasLookedForOverride) == SwitchValueState.HasLookedForOverride)
{
return(true);
}
// 3. The switch has a valid value, but we need to check for overrides.
// Regardless of whether or not the switch has an override, we need to update the value to reflect
// the fact that we checked for overrides.
bool overrideValue;
if (AppContextDefaultValues.TryGetSwitchOverride(switchName, out overrideValue))
{
// we found an override!
isEnabled = overrideValue;
}
// Update the switch in the dictionary to mark it as 'checked for override'
s_switchMap[switchName] = (isEnabled ? SwitchValueState.HasTrueValue : SwitchValueState.HasFalseValue)
| SwitchValueState.HasLookedForOverride;
return(true);
}
else
{
// The value is NOT in the dictionary
// In this case we need to see if we have an override defined for the value.
// There are 2 cases:
// 1. The value has an override specified. In this case we need to add the value to the dictionary
// and mark it as checked for overrides
// Example: In a servicing event, System.Xml introduces a switch and an override is specified.
// The value is not found in mscorlib (as System.Xml ships independent of mscorlib)
// 2. The value does not have an override specified
// In this case, we want to capture the fact that we looked for a value and found nothing by adding
// an entry in the dictionary with the 'sentinel' value of 'SwitchValueState.UnknownValue'.
// Example: This will prevent us from trying to find overrides for values that we don't have in the dictionary
// 1. The value has an override specified.
bool overrideValue;
if (AppContextDefaultValues.TryGetSwitchOverride(switchName, out overrideValue))
{
isEnabled = overrideValue;
// Update the switch in the dictionary to mark it as 'checked for override'
s_switchMap[switchName] = (isEnabled ? SwitchValueState.HasTrueValue : SwitchValueState.HasFalseValue)
| SwitchValueState.HasLookedForOverride;
return(true);
}
// 2. The value does not have an override.
s_switchMap[switchName] = SwitchValueState.UnknownValue;
}
}
return(false); // we did not find a value for the switch
}
