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// Licensed to the .NET Foundation under one or more agreements.
// The .NET Foundation licenses this file to you under the MIT license.
using System.Diagnostics;
using System.Globalization;
namespace System.Configuration
{
// This is a class that abstracts the usage of the override mode setting
internal struct OverrideModeSetting
{
private const byte ApiDefinedLegacy = 0x10; // allowOverride was set through the API
private const byte ApiDefinedNewMode = 0x20; // overrideMode was set through the API
// allowOverride or overrideMode was set through the API
private const byte ApiDefinedAny = ApiDefinedLegacy | ApiDefinedNewMode;
private const byte XmlDefinedLegacy = 0x40; // allowOverride was defined in the XML
private const byte XmlDefinedNewMode = 0x80; // overrideMode was defined in the XML
// overrideMode or allowOverride was defined in the XML
private const byte XmlDefinedAny = XmlDefinedLegacy | XmlDefinedNewMode;
private const byte ModeMask = 0x0f; // logical AND this with the current value to get the mode part only
private byte _mode;
// Default for section is ALLOW
internal static readonly OverrideModeSetting s_sectionDefault = new OverrideModeSetting { _mode = (byte)OverrideMode.Allow };
// Default for location tags is INHERIT. Note that we do not make the value as existent in the XML or specified by the API
internal static readonly OverrideModeSetting s_locationDefault = new OverrideModeSetting { _mode = (byte)OverrideMode.Inherit };
internal static OverrideModeSetting CreateFromXmlReadValue(bool allowOverride)
{
// Create a mode from the old "allowOverride" attribute in the xml
// The conversion is true -> OverrideMode.Inherit
// The conversion is false -> OverrideMode.Deny
// This is consistent with Whidbey where true means true unless there is a false somewhere above
OverrideModeSetting result = default;
result.SetMode(allowOverride ? OverrideMode.Inherit : OverrideMode.Deny);
result._mode |= XmlDefinedLegacy;
return result;
}
internal static OverrideModeSetting CreateFromXmlReadValue(OverrideMode mode)
{
OverrideModeSetting result = default;
result.SetMode(mode);
result._mode |= XmlDefinedNewMode;
return result;
}
internal static OverrideMode ParseOverrideModeXmlValue(string value, XmlUtil xmlUtil) =>
// 'value' is the string representation of OverrideMode enum
// Try to parse the string to the enum and generate errors if not possible
value switch
{
BaseConfigurationRecord.OverrideModeInherit => OverrideMode.Inherit,
BaseConfigurationRecord.OverrideModeAllow => OverrideMode.Allow,
BaseConfigurationRecord.OverrideModeDeny => OverrideMode.Deny,
_ => throw new ConfigurationErrorsException(
SR.Config_section_override_mode_attribute_invalid,
xmlUtil),
};
internal static bool CanUseSameLocationTag(OverrideModeSetting x, OverrideModeSetting y)
{
// This function tells if the two OverrideModeSettings are compatible enough to be used in only one location tag
// or each of them should go to a separate one
// The rules here are ( in order of importance )
// 1. The effective mode is the same ( we will use only the new OverrideMode to compare )
// 2. When the mode was changed( i.e. API change ) - both must be changed the same way ( i.e. using either allowOverride or OverrideMode )
// 3. When mode was not changed the XML - they must've been the same in the xml ( i.e. allowOverride specified on both, or overrideMode or neither of them )
bool result = x.OverrideMode == y.OverrideMode;
if (!result) return false;
// Check for an API change for each setting first
// If one mode was set through the API - the other mode has to be set in the same way through the API or has to be using the same type in the xml
// Handle case where "x" was API modified
if ((x._mode & ApiDefinedAny) != 0) result = IsMatchingApiChangedLocationTag(x, y);
// Handle case where "y" was API modified
else
{
if ((y._mode & ApiDefinedAny) != 0) result = IsMatchingApiChangedLocationTag(y, x);
// Handle case where neither "x" nor "y" was API modified
else
{
// If one of the settings was XML defined - they are a match only if both were XML defined in the same way
if (((x._mode & XmlDefinedAny) != 0) ||
((y._mode & XmlDefinedAny) != 0))
result = (x._mode & XmlDefinedAny) == (y._mode & XmlDefinedAny);
// Neither "x" nor "y" was XML defined - they are a match since they can both go
// to a default <location> with no explicit mode setting written out
}
}
return result;
}
private static bool IsMatchingApiChangedLocationTag(OverrideModeSetting x, OverrideModeSetting y)
{
// x must be a changed through the API setting
// Returns true if x and y can share the same location tag
Debug.Assert((x._mode & ApiDefinedAny) != 0);
bool result = false;
if ((y._mode & ApiDefinedAny) != 0)
{
// If "y" was modified through the API as well - the modified setting must be the same ( i.e. allowOvverride or overrideMode must be modified in both settings )
result = (x._mode & ApiDefinedAny) == (y._mode & ApiDefinedAny);
}
else
{
// "y" was not API modified - they are still a match if "y" was a XML setting from the same mode
if ((y._mode & XmlDefinedAny) != 0)
{
// "x" was API changed in Legacy and "y" was XML defined in Legacy
result = (((x._mode & ApiDefinedLegacy) != 0) && ((y._mode & XmlDefinedLegacy) != 0)) ||
// "x" was API changed in New and "y" was XML defined in New
(((x._mode & ApiDefinedNewMode) != 0) && ((y._mode & XmlDefinedNewMode) != 0));
}
// "y" was not API or XML modified - since "x" was API modified - they are not a match ( i.e. "y" should go to an <location> with no explicit mode written out )
}
return result;
}
internal bool IsDefaultForSection
{
get
{
// Returns true if the current value of the overrideMode setting is the default one on a section declaration
// The current default value for a section's overrideMode ( i.e. overrideModeDefault ) is Allow ( see CreateDefaultForSection )
// It would've been nice not to repeat that rule here but since OverrideMode.Inherited means the same in this specific context we have to
// I.e. the default for a section is both Allow and Inherited. In this case they mean the same
OverrideMode mode = OverrideMode;
// Return true if mode is Allow or Inherit
return (mode == OverrideMode.Allow) || (mode == OverrideMode.Inherit);
}
}
internal bool IsDefaultForLocationTag
{
get
{
// Returns true if the current setting is the same as the default value for a location tag
// Note that if the setting was an API modified or XmlDefined it is not a default since it
// cannot go to the default <location> tag which does not explicitlly specify a mode
OverrideModeSetting defaultSetting = s_locationDefault;
return (defaultSetting.OverrideMode == OverrideMode) &&
((_mode & ApiDefinedAny) == 0) &&
((_mode & XmlDefinedAny) == 0);
}
}
internal bool IsLocked => OverrideMode == OverrideMode.Deny;
internal string LocationTagXmlString
{
get
{
// Returns the string for this setting which is to be written in the xml <location> tag
string result = string.Empty;
bool needToWrite = false;
bool useLegacy = false;
// If there was an API change - it has highest priority
if ((_mode & ApiDefinedAny) != 0)
{
// Whichever was changed by the API dictates what is to be written
useLegacy = (_mode & ApiDefinedLegacy) != 0;
needToWrite = true;
Debug.Assert(useLegacy || ((_mode & ApiDefinedNewMode) != 0));
}
// It wasn't changed through the API - check if it was read originally from the XML
else
{
if ((_mode & XmlDefinedAny) != 0)
{
// Whatever was defined in the XML is to be written out
useLegacy = (_mode & XmlDefinedLegacy) != 0;
needToWrite = true;
Debug.Assert(useLegacy || ((_mode & XmlDefinedNewMode) != 0));
}
}
if (needToWrite)
{
string value;
string attrib;
if (useLegacy)
{
// Legacy - allowOverride
attrib = BaseConfigurationRecord.LocationAllowOverrideAttribute;
value = AllowOverride
? BaseConfigurationRecord.KeywordTrue
: BaseConfigurationRecord.KeywordFalse;
}
else
{
attrib = BaseConfigurationRecord.LocationOverrideModeAttribute;
value = OverrideModeXmlValue;
}
result = string.Format(CultureInfo.InvariantCulture,
BaseConfigurationRecord.KeywordLocationOverrideModeString, attrib, value);
}
return result;
}
}
internal string OverrideModeXmlValue
{
get
{
// Returns the xml (string) value of the current setting for override mode
switch (OverrideMode)
{
case OverrideMode.Inherit:
return BaseConfigurationRecord.OverrideModeInherit;
case OverrideMode.Allow:
return BaseConfigurationRecord.OverrideModeAllow;
case OverrideMode.Deny:
return BaseConfigurationRecord.OverrideModeDeny;
default:
Debug.Fail("Missing xml keyword for OverrideMode enum value");
break;
}
return null;
}
}
// Use this method to change only the value of the setting when not done through the public API
internal void ChangeModeInternal(OverrideMode mode)
{
SetMode(mode);
}
// Properties to enable external chnages to the mode.
// Note that those changes will be tracked as made by the public API
// There shouldn't be a reason for those to be used except in this specific case
internal OverrideMode OverrideMode
{
get { return (OverrideMode)(_mode & ModeMask); }
set
{
// Note that changing the mode through the API ( which is the purpose of this setter )
// overrides the setting in the XML ( if any )
// and hence we dont keep a track of it anymore
// Error condition: We do not allow changes to the mode through both AllowOverride and OverrideMode
// If one was changed first we require that API users stick with it
VerifyConsistentChangeModel(ApiDefinedNewMode);
SetMode(value);
_mode |= ApiDefinedNewMode;
}
}
internal bool AllowOverride
{
get
{
bool result = true;
switch (OverrideMode)
{
case OverrideMode.Inherit:
case OverrideMode.Allow:
break;
case OverrideMode.Deny:
result = false;
break;
default:
Debug.Fail("Unrecognized OverrideMode");
break;
}
return result;
}
set
{
// Note that changing the mode through the API ( which is the purpose of this setter )
// overrides the setting in the XML ( if any )
// and hence we dont keep a track of it anymore
// Error condition: We do not allow changes to the mode through both AllowOverride and OverrideMode
// If one was changed first we require that API users stick with it
VerifyConsistentChangeModel(ApiDefinedLegacy);
SetMode(value ? OverrideMode.Inherit : OverrideMode.Deny);
_mode |= ApiDefinedLegacy;
}
}
private void SetMode(OverrideMode mode)
{
_mode = (byte)mode;
}
private void VerifyConsistentChangeModel(byte required)
{
// The required API change model ( i.e. was allowOverride used or OverrideMode ) should be consistent
// I.e. its not possible to change both on the same OverrideModeSetting object
byte current = (byte)(_mode & ApiDefinedAny);
// Shows whats the current setting: 0 ( none ), ApiDefinedLegacy or ApiDefinedNew
if ((current != 0) && (current != required))
throw new ConfigurationErrorsException(SR.Cannot_change_both_AllowOverride_and_OverrideMode);
}
}
}
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