| // Copyright 2016 The Tulsi Authors. All rights reserved. |
| // |
| // Licensed under the Apache License, Version 2.0 (the "License"); |
| // you may not use this file except in compliance with the License. |
| // You may obtain a copy of the License at |
| // |
| // http://www.apache.org/licenses/LICENSE-2.0 |
| // |
| // Unless required by applicable law or agreed to in writing, software |
| // distributed under the License is distributed on an "AS IS" BASIS, |
| // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| // See the License for the specific language governing permissions and |
| // limitations under the License. |
| |
| import Foundation |
| |
| |
| /// Provides helper methods to extract meaningful error messages from Bazel stderr output. |
| struct BazelErrorExtractor { |
| static let DefaultErrors = 3 |
| |
| static func firstErrorLinesFromData(_ data: Data, maxErrors: Int = DefaultErrors) -> String? { |
| guard let stderr = NSString(data: data, encoding: String.Encoding.utf8.rawValue) else { return nil } |
| return firstErrorLinesFromString(stderr as String, maxErrors: maxErrors) |
| } |
| |
| static func firstErrorLinesFromString(_ output: String, maxErrors: Int = DefaultErrors) -> String? { |
| func isNewLogMessage(_ line: String) -> Bool { |
| for newLogMessagePrefix in ["ERROR:", "INFO:", "WARNING:"] { |
| if line.hasPrefix(newLogMessagePrefix) { |
| return true |
| } |
| } |
| return false |
| } |
| |
| var errorMessages = [String]() |
| var tracebackErrorMessages = Set<String>() |
| var activeTraceback = [String]() |
| |
| for line in output.components(separatedBy: "\n") { |
| if !activeTraceback.isEmpty { |
| if isNewLogMessage(line) { |
| if !errorMessages.isEmpty { |
| let lastMessageIndex = errorMessages.count - 1 |
| errorMessages[lastMessageIndex].append(activeTraceback.joined(separator: "\n")) |
| tracebackErrorMessages.insert(errorMessages[lastMessageIndex]) |
| } |
| activeTraceback = [] |
| } else { |
| activeTraceback.append(line) |
| } |
| } else if (line.hasPrefix("Traceback")) { |
| activeTraceback.append(line) |
| } |
| |
| if (line.hasPrefix("ERROR:")) { |
| errorMessages.append(line) |
| } |
| } |
| |
| if !activeTraceback.isEmpty && !errorMessages.isEmpty { |
| let lastMessageIndex = errorMessages.count - 1 |
| errorMessages[lastMessageIndex].append(activeTraceback.joined(separator: "\n")) |
| tracebackErrorMessages.insert(errorMessages[lastMessageIndex]) |
| } |
| |
| // Display only up to 'maxErrors' number of errors to the user (including any |
| // associated traceback), but also check if any remaining errors include a traceback. |
| // Errors with a traceback should always be displayed regardless of how many errors are |
| // already being printed. |
| var errorSnippet = errorMessages.prefix(maxErrors).joined(separator: "\n") |
| tracebackErrorMessages.subtract(errorMessages.prefix(maxErrors)) |
| errorSnippet.append(tracebackErrorMessages.joined(separator: "\n")) |
| |
| if maxErrors < errorMessages.count { |
| errorSnippet += "\n..." |
| } |
| return errorSnippet |
| } |
| |
| static func firstErrorLinesOrLastLinesFromString(_ output: String, |
| maxErrors: Int = DefaultErrors) -> String? { |
| if let errorLines = firstErrorLinesFromString(output, maxErrors: maxErrors) { |
| return errorLines |
| } |
| let errorLines = output.components(separatedBy: "\n").filter({ !$0.isEmpty }) |
| let numErrorLinesToShow = min(errorLines.count, maxErrors) |
| var errorSnippet = errorLines.suffix(numErrorLinesToShow).joined(separator: "\n") |
| if numErrorLinesToShow < errorLines.count { |
| errorSnippet = "...\n" + errorSnippet |
| } |
| return errorSnippet |
| } |
| |
| private init() { |
| } |
| } |