refactor and cleanup [skip ci]

submodules/Postbox/Sources/MessageHistoryTextIndexTable.swift

@@ -0,0 +1,99 @@
+import Foundation
+
+private func collectionId(_ peerId: PeerId) -> String {
+    return "p\(UInt64(bitPattern: peerId.toInt64()))"
+}
+
+private func itemId(_ messageId: MessageId) -> String {
+    return "p\(UInt64(bitPattern: messageId.peerId.toInt64()))a\(UInt32(bitPattern: messageId.namespace))b\(UInt32(bitPattern: messageId.id))"
+}
+
+private func messageTags(_ tags: MessageTags) -> String {
+    var result = ""
+    for tag in tags {
+        if !result.isEmpty {
+            result += " "
+        }
+        result += "t\(tag.rawValue)"
+    }
+    return result
+}
+
+private func parseMessageId(_ value: String) -> MessageId? {
+    if !value.hasPrefix("p") {
+        return nil
+    }
+    guard let aRange = value.range(of: "a") else {
+        return nil
+    }
+    guard let bRange = value.range(of: "b") else {
+        return nil
+    }
+    let pString = value[value.index(value.startIndex, offsetBy: 1) ..< aRange.lowerBound]
+    let nString = value[aRange.upperBound ..< bRange.lowerBound]
+    let iString = value[bRange.upperBound ..< value.endIndex]
+    
+    guard let pValue = UInt64(pString) else {
+        return nil
+    }
+    guard let nValue = UInt32(nString) else {
+        return nil
+    }
+    guard let iValue = UInt32(iString) else {
+        return nil
+    }
+    
+    return MessageId(peerId: PeerId(Int64(bitPattern: pValue)), namespace: Int32(bitPattern: nValue), id: Int32(bitPattern: iValue))
+}
+
+private let alphanumerics = CharacterSet.alphanumerics
+
+final class MessageHistoryTextIndexTable {
+    static func tableSpec(_ id: Int32) -> ValueBoxFullTextTable {
+        return ValueBoxFullTextTable(id: id)
+    }
+    
+    private let valueBox: ValueBox
+    private let table: ValueBoxFullTextTable
+    
+    init(valueBox: ValueBox, table: ValueBoxFullTextTable) {
+        self.valueBox = valueBox
+        self.table = table
+    }
+    
+    func add(messageId: MessageId, text: String, tags: MessageTags) {
+        self.valueBox.fullTextSet(self.table, collectionId: collectionId(messageId.peerId), itemId: itemId(messageId), contents: text, tags: messageTags(tags))
+    }
+    
+    func remove(messageId: MessageId) {
+        self.valueBox.fullTextRemove(self.table, itemId: itemId(messageId))
+    }
+    
+    func search(peerId: PeerId?, text: String, tags: MessageTags?) -> [MessageId] {
+        var escapedText = String(text.map({ c in
+            var codeUnits: [UnicodeScalar] = []
+            for codeUnit in String(c).unicodeScalars {
+                codeUnits.append(codeUnit)
+            }
+            for codeUnit in codeUnits {
+                if !alphanumerics.contains(codeUnit) {
+                    return " "
+                }
+            }
+            return c
+        }))
+        if !escapedText.isEmpty {
+            escapedText += "*"
+        }
+        var result: [MessageId] = []
+        self.valueBox.fullTextMatch(self.table, collectionId: peerId.flatMap { collectionId($0) }, query: escapedText, tags: tags.flatMap(messageTags), values: { _, itemId in
+            if let messageId = parseMessageId(itemId) {
+                result.append(messageId)
+            } else {
+                assertionFailure()
+            }
+            return true
+        })
+        return result
+    }
+}