Merge pull request #1036 from ahoppen/ahoppen/chunk-end-marker

Author: ahoppen

Sources/LSPLogging/SplitLogMessage.swift

@@ -12,8 +12,8 @@
 
 /// Splits `message` on newline characters such that each chunk is at most `maxChunkSize` bytes long.
 ///
-/// The intended use case for this is to split compiler arguments into multiple chunks so that each chunk doesn't exceed
-/// the maximum message length of `os_log` and thus won't get truncated.
+/// The intended use case for this is to split compiler arguments and a file's contents into multiple chunks so
+/// that each chunk doesn't exceed the maximum message length of `os_log` and thus won't get truncated.
 ///
 ///  - Note: This will only split along newline boundary. If a single line is longer than `maxChunkSize`, it won't be
 ///    split. This is fine for compiler argument splitting since a single argument is rarely longer than 800 characters.
@@ -23,6 +23,12 @@ public func splitLongMultilineMessage(message: String, maxChunkSize: Int = 800)
     if let lastChunk = chunks.last, lastChunk.utf8.count + line.utf8.count < maxChunkSize {
       chunks[chunks.count - 1] += "\n" + line
     } else {
+      if !chunks.isEmpty {
+        // Append an end marker to the last chunk so that os_log doesn't truncate trailing whitespace,
+        // which would modify the source contents.
+        // Empty newlines are important so the offset of the request is correct.
+        chunks[chunks.count - 1] += "\n--- End Chunk"
+      }
       chunks.append(String(line))
     }
   }