Enable all indexes (index, partition, tag) to be nilable.

src/dodb.cr

@@ -173,6 +173,24 @@ abstract class DODB::Storage(V)
 		end
 	end
 
+	def new_nilable_partition(name : String, &block : Proc(V, String | DODB::NoIndex))
+		CachedPartition(V).new(self, @directory_name, name, block).tap do |table|
+			@indexers << table
+		end
+	end
+
+	def new_nilable_uncached_partition(name : String, &block : Proc(V, String | DODB::NoIndex))
+		Partition(V).new(self, @directory_name, name, block).tap do |table|
+			@indexers << table
+		end
+	end
+
+	def new_nilable_RAM_partition(name : String, &block : Proc(V, String | DODB::NoIndex))
+		RAMOnlyPartition(V).new(self, @directory_name, name, block).tap do |table|
+			@indexers << table
+		end
+	end
+
 	def get_partition(table_name : String, partition_name : String)
 		partition = @indexers.find &.name.==(table_name)
 
@@ -201,6 +219,24 @@ abstract class DODB::Storage(V)
 		end
 	end
 
+	def new_nilable_tags(name : String, &block : Proc(V, Array(String) | DODB::NoIndex))
+		CachedTags(V).new(self, @directory_name, name, block).tap do |tags|
+			@indexers << tags
+		end
+	end
+
+	def new_nilable_uncached_tags(name : String, &block : Proc(V, Array(String) | DODB::NoIndex))
+		Tags(V).new(self, @directory_name, name, block).tap do |tags|
+			@indexers << tags
+		end
+	end
+
+	def new_nilable_RAM_tags(name : String, &block : Proc(V, Array(String) | DODB::NoIndex))
+		RAMOnlyTags(V).new(self, @directory_name, name, block).tap do |tags|
+			@indexers << tags
+		end
+	end
+
 	def get_tags(name, key : String)
 		tag = @indexers.find &.name.==(name)
 

src/dodb/index.cr

@@ -17,6 +17,8 @@ class DODB::Index(V) < DODB::Indexer(V)
 	def check!(key, value, old_value)
 		index_key = key_proc.call value
 
+		return if index_key.is_a? NoIndex
+
 		symlink = file_path_index index_key.to_s
 
 		if ::File.symlink? symlink
@@ -33,7 +35,6 @@ class DODB::Index(V) < DODB::Indexer(V)
 
 	def index(key, value)
 		index_key = key_proc.call value
-
 		return if index_key.is_a? NoIndex
 
 		symlink = file_path_index index_key
@@ -45,7 +46,6 @@ class DODB::Index(V) < DODB::Indexer(V)
 
 	def deindex(key, value)
 		index_key = key_proc.call value
-
 		return if index_key.is_a? NoIndex
 
 		symlink = file_path_index index_key
@@ -151,6 +151,7 @@ class DODB::CachedIndex(V) < DODB::Index(V)
 
 	def check!(key, value, old_value)
 		index_key = key_proc.call value
+		return if index_key.is_a? NoIndex
 
 		if data[index_key]?
 			# In case both old and new values are pointing to the same key,
@@ -170,19 +171,17 @@ class DODB::CachedIndex(V) < DODB::Index(V)
 	end
 
 	def index(key, value)
-		super(key, value)
-
 		index_key = key_proc.call value
 		return if index_key.is_a? NoIndex
+		super(key, value)
 
 		@data[index_key] = key.to_i
 	end
 
 	def deindex(key, value)
-		super(key, value)
-
 		index_key = key_proc.call value
 		return if index_key.is_a? NoIndex
+		super(key, value)
 
 		@data.delete index_key
 	end

src/dodb/no_index.cr

@@ -1,5 +1,11 @@
 
 class DODB::NoIndex
+	include JSON::Serializable
+
+	def_clone
+
+	def initialize()
+	end
 end
 
 module DODB

src/dodb/partition.cr

@@ -4,7 +4,7 @@ require "./indexer.cr"
 
 class DODB::Partition(V) < DODB::Indexer(V)
 	property name         : String
-	property key_proc     : Proc(V, String)
+	property key_proc     : Proc(V, String | NoIndex) | Proc(V, String)
 	getter   storage_root : String
 
 	# Required to remove an entry in the DB.
@@ -20,19 +20,18 @@ class DODB::Partition(V) < DODB::Indexer(V)
 
 	def index(key, value)
 		partition = key_proc.call value
+		return if partition.is_a? NoIndex
 
 		symlink = get_partition_symlink(partition, key)
 
 		Dir.mkdir_p ::File.dirname symlink
 
-		# FIXME: Should not happen anymore. Should we remove this?
-		::File.delete symlink if ::File.exists? symlink
-
 		::File.symlink get_data_symlink(key), symlink
 	end
 
 	def deindex(key, value)
 		partition = key_proc.call value
+		return if partition.is_a? NoIndex
 
 		symlink = get_partition_symlink(partition, key)
 
@@ -111,8 +110,9 @@ class DODB::CachedPartition(V) < DODB::Partition(V)
 	end
 
 	def index(key, value)
-		super(key, value)
 		partition = key_proc.call value
+		return if partition.is_a? NoIndex
+		super(key, value)
 
 		array = if v = @data[partition]?
 			v
@@ -125,8 +125,9 @@ class DODB::CachedPartition(V) < DODB::Partition(V)
 	end
 
 	def deindex(key, value)
-		super(key, value)
 		partition = key_proc.call value
+		return if partition.is_a? NoIndex
+		super(key, value)
 
 		if v = @data[partition]?
 			v.delete key.to_i
@@ -178,6 +179,7 @@ end
 class DODB::RAMOnlyPartition(V) < DODB::CachedPartition(V)
 	def index(key, value)
 		partition = key_proc.call value
+		return if partition.is_a? NoIndex
 
 		array = if v = @data[partition]?
 			v
@@ -191,6 +193,7 @@ class DODB::RAMOnlyPartition(V) < DODB::CachedPartition(V)
 
 	def deindex(key, value)
 		partition = key_proc.call value
+		return if partition.is_a? NoIndex
 
 		if v = @data[partition]?
 			v.delete key.to_i

src/dodb/tags.cr

@@ -2,7 +2,7 @@ require "file_utils"
 
 class DODB::Tags(V) < DODB::Indexer(V)
 	property name         : String
-	property key_proc     : Proc(V, Array(String))
+	property key_proc     : Proc(V, Array(String) | NoIndex) | Proc(V, Array(String))
 	getter   storage_root : String
 
 	# Required to remove an entry in the DB.
@@ -18,6 +18,7 @@ class DODB::Tags(V) < DODB::Indexer(V)
 
 	def index(key, value)
 		indices = key_proc.call(value)
+		return if indices.is_a? NoIndex
 
 		indices.each do |i|
 			symlink = get_tagged_entry_path(i, key)
@@ -30,6 +31,7 @@ class DODB::Tags(V) < DODB::Indexer(V)
 
 	def deindex(key, value)
 		indices = key_proc.call(value)
+		return if indices.is_a? NoIndex
 
 		indices.each do |i|
 			symlink = get_tagged_entry_path(i, key)
@@ -131,8 +133,9 @@ class DODB::CachedTags(V) < DODB::Tags(V)
 	property data = Hash(String, Array(Int32)).new
 
 	def index(key, value)
-		super(key, value)
 		indices = key_proc.call value
+		return if indices.is_a? NoIndex
+		super(key, value)
 
 		indices.each do |tag|
 			array = if v = @data[tag]?
@@ -147,8 +150,9 @@ class DODB::CachedTags(V) < DODB::Tags(V)
 	end
 
 	def deindex(key, value)
-		super(key, value)
 		indices = key_proc.call value
+		return if indices.is_a? NoIndex
+		super(key, value)
 
 		indices.each do |tag|
 			if v = @data[tag]?
@@ -204,6 +208,7 @@ end
 class DODB::RAMOnlyTags(V) < DODB::CachedTags(V)
 	def index(key, value)
 		indices = key_proc.call value
+		return if indices.is_a? NoIndex
 
 		indices.each do |tag|
 			array = if v = @data[tag]?
@@ -219,6 +224,7 @@ class DODB::RAMOnlyTags(V) < DODB::CachedTags(V)
 
 	def deindex(key, value)
 		indices = key_proc.call value
+		return if indices.is_a? NoIndex
 
 		indices.each do |tag|
 			if v = @data[tag]?