[#2091] Minor Enhancements to Existing Regex Code (#2115)

* Enhance existing Regex code

* Consolidate typical Regex patterns

---------

Co-authored-by: Charisma Kausar <[email protected]>
Co-authored-by: Gokul Rajiv <[email protected]>
Co-authored-by: Marcus Tang <[email protected]>

src/main/java/reposense/authorship/FileInfoAnalyzer.java

@@ -22,6 +22,7 @@
 import reposense.model.RepoConfiguration;
 import reposense.system.LogsManager;
 import reposense.util.FileUtil;
+import reposense.util.StringsUtil;
 
 /**
  * Analyzes the target and information given in the {@link FileInfo}.
@@ -149,7 +150,7 @@ private void aggregateBlameAuthorModifiedAndDateInfo(RepoConfiguration config, F
  blameResults = getGitBlameWithPreviousAuthorsResult(config, fileInfo.getPath());
  }
 
- String[] blameResultLines = blameResults.split("\n");
+ String[] blameResultLines = StringsUtil.NEWLINE.split(blameResults);
  Path filePath = Paths.get(fileInfo.getPath());
  LocalDateTime sinceDate = config.getSinceDate();
  LocalDateTime untilDate = config.getUntilDate();

src/main/java/reposense/authorship/FileInfoExtractor.java

@@ -27,6 +27,7 @@
 import reposense.model.RepoConfiguration;
 import reposense.system.LogsManager;
 import reposense.util.FileUtil;
+import reposense.util.StringsUtil;
 
 /**
  * Extracts out all the relevant {@code FileInfo} from the repository.
@@ -146,9 +147,9 @@ public Set<Path> getFiles(RepoConfiguration repoConfig, boolean isBinaryFile) {
  // Gets rid of files with invalid directory name and filters by the {@code isBinaryFile} flag
  return modifiedFileList.stream()
  .filter(file -> isBinaryFile == file.startsWith(BINARY_FILE_LINE_DIFF_RESULT))
- .map(file -> file.split("\t")[2])
+ .map(file -> StringsUtil.TAB.split(file)[2])
  .filter(FileUtil::isValidPathWithLogging)
- .map(filteredFile -> Paths.get(filteredFile))
+ .map(Paths::get)
  .collect(Collectors.toCollection(HashSet::new));
  }
 
@@ -164,7 +165,7 @@ private void setLinesToTrack(FileInfo fileInfo, String fileDiffResult) {
  // skips the header, index starts from 1
  for (int sectionIndex = 1; sectionIndex < linesChangedChunk.length; sectionIndex++) {
  String linesChangedInSection = linesChangedChunk[sectionIndex];
- String[] linesChanged = linesChangedInSection.split("\n");
+ String[] linesChanged = StringsUtil.NEWLINE.split(linesChangedInSection);
  int startingLineNumber = getStartingLineNumber(linesChanged[LINE_CHANGED_HEADER_INDEX]);
 
  // mark all untouched lines between sections as untracked

src/main/java/reposense/git/GitCatFile.java

@@ -10,6 +10,7 @@
 
 import reposense.git.exception.CommitNotFoundException;
 import reposense.system.LogsManager;
+import reposense.util.StringsUtil;
 
 /**
  * Contains git cat file related functionalities.
@@ -31,7 +32,7 @@ public static List<String> getParentCommits(String root, String commitHash) thro
  try {
  String output = runCommand(rootPath, catFileCommand);
  List<String> parentCommits = new ArrayList<>();
- for (String line : output.split("\n")) {
+ for (String line : StringsUtil.NEWLINE.split(output)) {
  if (line.startsWith("parent")) {
  parentCommits.add(line.substring(7).trim());
  }

src/main/java/reposense/git/GitConfig.java

@@ -6,10 +6,12 @@
 import java.util.List;
 import java.util.logging.Level;
 import java.util.logging.Logger;
+import java.util.regex.Pattern;
 import java.util.stream.Collectors;
 
 import reposense.system.CommandRunner;
 import reposense.system.LogsManager;
+import reposense.util.StringsUtil;
 
 /**
  * Contains git config related functionalities.
@@ -36,10 +38,12 @@ public class GitConfig {
  * @return a list of string arrays where 0-index is key and 1-index is value.
  */
  public static List<String[]> getGlobalGitLfsConfig() {
+ Pattern equals = Pattern.compile("=");
+
  try {
  String gitConfig = getGitGlobalConfig();
- return Arrays.stream(gitConfig.split("\n"))
- .map(line -> line.split("="))
+ return Arrays.stream(StringsUtil.NEWLINE.split(gitConfig))
+ .map(equals::split)
  .filter(line -> line[0].equals(FILTER_LFS_SMUDGE_KEY) || line[0].equals((FILTER_LFS_PROCESS_KEY)))
  .collect(Collectors.toList());
  } catch (RuntimeException re) {

src/main/java/reposense/git/GitDiff.java

@@ -7,6 +7,9 @@
 import java.util.Arrays;
 import java.util.List;
 
+import reposense.util.StringsUtil;
+
+
 /**
  * Contains git diff related functionalities.
  * Git diff is responsible for obtaining the changes between commits, commit and working tree, etc.
@@ -32,6 +35,6 @@ public static List<String> getModifiedFilesList(Path repoRoot) {
  String diffCommand = String.format("git diff --ignore-submodules=all --numstat %s %s",
  EMPTY_TREE_HASH, CHECKED_OUT_COMMIT_REFERENCE);
  String diffResult = runCommand(repoRoot.toAbsolutePath(), diffCommand);
- return Arrays.asList(diffResult.split("\n"));
+ return Arrays.asList(StringsUtil.NEWLINE.split(diffResult));
  }
 }

src/main/java/reposense/git/GitLog.java

@@ -11,6 +11,7 @@
 
 import reposense.model.Author;
 import reposense.model.RepoConfiguration;
+import reposense.util.StringsUtil;
 
 /**
  * Contains git log related functionalities.
@@ -69,8 +70,8 @@ public static List<String[]> getFileAuthors(RepoConfiguration config, String fil
  command += " " + addQuotesForFilePath(filePath);
 
  String result = runCommand(rootPath, command);
- return Arrays.stream(result.split("\n"))
- .map(authorAndEmailLine -> authorAndEmailLine.split("\t"))
+ return Arrays.stream(StringsUtil.NEWLINE.split(result))
+ .map(StringsUtil.TAB::split)
  .map(authorAndEmailArray -> authorAndEmailArray.length == 1
  ? new String[] {authorAndEmailArray[0], DEFAULT_EMAIL_IF_MISSING}
  : authorAndEmailArray)

src/main/java/reposense/git/GitRemote.java

@@ -6,9 +6,11 @@
 import java.util.Map;
 import java.util.Optional;
 import java.util.logging.Logger;
+import java.util.regex.Pattern;
 
 import reposense.system.CommandRunner;
 import reposense.system.LogsManager;
+import reposense.util.StringsUtil;
 
 /**
  * Contains git remote related functionality.
@@ -27,6 +29,7 @@ public class GitRemote {
  * @return Map of keys of the form REMOTE_NAME(fetch) or REMOTE_NAME(push) to their corresponding remote URLs.
  */
  public static Map<String, String> getRemotes(String repoRoot) {
+ Pattern anyTabPattern = Pattern.compile("[ \\t]+");
  Map<String, String> remotes = new HashMap<>();
  String result;
  try {
@@ -36,8 +39,8 @@ public static Map<String, String> getRemotes(String repoRoot) {
  return remotes;
  }
 
- Arrays.stream(result.split("\n"))
- .map(s -> s.split("[ \\t]+"))
+ Arrays.stream(StringsUtil.NEWLINE.split(result))
+ .map(anyTabPattern::split)
  .forEach(l -> {
  if (l.length == 3) {
  // l[0]: remote name

src/main/java/reposense/git/GitRevList.java

@@ -10,6 +10,9 @@
 import java.util.Arrays;
 import java.util.List;
 
+import reposense.util.StringsUtil;
+
+
 /**
  * Contains git rev list related functionalities.
  * Git rev list is responsible for showing commit objects in reverse chronological order.
@@ -106,7 +109,7 @@ public static List<String> getRootCommits(String root) {
  String revListCommand = "git rev-list --max-parents=0 HEAD";
  Path rootPath = Paths.get(root);
  String output = runCommand(rootPath, revListCommand);
- return Arrays.asList(output.split("\n"));
+ return Arrays.asList(StringsUtil.NEWLINE.split(output));
  }
 
  /**

src/main/java/reposense/git/GitShortlog.java

@@ -13,6 +13,7 @@
 
 import reposense.model.Author;
 import reposense.model.RepoConfiguration;
+import reposense.util.StringsUtil;
 
 /**
  * Contains git shortlog related functionalities.
@@ -32,9 +33,9 @@ public static List<Author> getAuthors(RepoConfiguration config) {
  return Collections.emptyList();
  }
 
- String[] lines = summary.split("\n");
+ String[] lines = StringsUtil.NEWLINE.split(summary);
  return Arrays.stream(lines)
- .map(line -> new Author(line.split("\t")[1]))
+ .map(line -> new Author(StringsUtil.TAB.split(line)[1]))
  .collect(Collectors.toList());
  }
 

src/main/java/reposense/git/GitShow.java

@@ -15,6 +15,7 @@
 import reposense.git.exception.CommitNotFoundException;
 import reposense.model.CommitHash;
 import reposense.system.LogsManager;
+import reposense.util.StringsUtil;
 
 /**
  * Contains git show related functionalities.
@@ -36,7 +37,7 @@ public static CommitHash getExpandedCommitHash(String root, String shortCommitHa
 
  try {
  String output = runCommand(rootPath, showCommand);
- List<CommitHash> commitHashes = Arrays.stream(output.split("\n"))
+ List<CommitHash> commitHashes = Arrays.stream(StringsUtil.NEWLINE.split(output))
  .map(CommitHash::new).collect(Collectors.toList());
  if (commitHashes.size() > 1) {
  logger.warning(String.format("%s can be expanded to %d different commits, "

src/main/java/reposense/model/CommitHash.java

@@ -6,6 +6,7 @@
 import java.util.stream.Stream;
 
 import reposense.git.GitRevList;
+import reposense.util.StringsUtil;
 
 /**
  * Represents a git commit hash in {@code RepoConfiguration}.
@@ -77,7 +78,7 @@ public static Stream<CommitHash> getHashes(String root, String branchName, Commi
 
  String[] startAndEnd = entry.toString().split("\\.\\.");
  String revList = GitRevList.getCommitHashInRange(root, branchName, startAndEnd[0], startAndEnd[1]);
- return Arrays.stream(revList.split("\n"))
+ return Arrays.stream(StringsUtil.NEWLINE.split(revList))
  .map(CommitHash::new);
  }
 

src/main/java/reposense/util/StringsUtil.java

@@ -6,18 +6,19 @@
  * Contains strings related utilities.
  */
 public class StringsUtil {
-
+ public static final Pattern NEWLINE = Pattern.compile("\n");
+ public static final Pattern TAB = Pattern.compile("\t");
+ public static final Pattern NUMERIC = Pattern.compile("^\\d+$");
  private static final Pattern SPECIAL_SYMBOLS = Pattern.compile("[@;:&/\\\\!<>{}%#\"\\-='()\\[\\].+*?^$|]");
 
  /**
  * Filters the {@code text}, returning only the lines that matches the given {@code regex}.
  */
  public static String filterText(String text, String regex) {
- String[] split = text.split("\n");
  StringBuilder sb = new StringBuilder();
  Pattern regexPattern = Pattern.compile(regex);
 
- for (String line: split) {
+ for (String line: NEWLINE.split(text)) {
  if (regexPattern.matcher(line).matches()) {
  sb.append(line).append("\n");
  }
@@ -91,6 +92,6 @@ public static String removeTrailingBackslash(String string) {
  * Returns true iff {@code string} is purely numeric.
  */
  public static boolean isNumeric(String string) {
- return Pattern.compile("^\\d+$").matcher(string).matches();
+ return NUMERIC.matcher(string).matches();
  }
 }

src/test/java/reposense/util/TestUtil.java

@@ -31,7 +31,6 @@ public class TestUtil {
  + ">> %s\n";
 
  private static final String MESSAGE_LINES_LENGTH_DIFFERENT = "The files' lines count do not match.";
- private static final String TAB_SPLITTER = "\t";
  private static final String MOVED_FILE_INDICATION = "=> ";
  private static final int STAT_FILE_PATH_INDEX = 2;
 
@@ -54,10 +53,10 @@ public static boolean compareFileContents(Path expected, Path actual, int maxTra
 
  System.out.println(String.format(MESSAGE_COMPARING_FILES, expected, actual));
 
- String[] expectedContent = new String(Files.readAllBytes(expected))
- .replace("\r", "").split("\n");
- String[] actualContent = new String(Files.readAllBytes(actual))
- .replace("\r", "").split("\n");
+ String[] expectedContent = StringsUtil.NEWLINE.split(new String(Files.readAllBytes(expected))
+ .replace("\r", ""));
+ String[] actualContent = StringsUtil.NEWLINE.split(new String(Files.readAllBytes(actual))
+ .replace("\r", ""));
 
  for (int i = 0; i < Math.min(expectedContent.length, actualContent.length); i++) {
  if (!expectedContent[i].equals(actualContent[i])) {
@@ -197,7 +196,7 @@ public static boolean compareNumberFilesChanged(int expectedNumberFilesChanged,
  */
  private static Set<String> getFilesChangedInCommit(String rawCommitInfo) {
  Set<String> filesChanged = new HashSet<>();
- String[] commitInfo = rawCommitInfo.replaceAll("\n+$", "").split("\n");
+ String[] commitInfo = StringsUtil.NEWLINE.split(rawCommitInfo.replaceAll("\n+$", ""));
  int fileChangedNum = Integer.parseInt(commitInfo[commitInfo.length - 1].trim().split(" ")[0]);
  for (int fileNum = 0; fileNum < fileChangedNum; fileNum++) {
  filesChanged.add(getFileChanged(commitInfo[commitInfo.length - 2 - fileNum]));
@@ -209,7 +208,7 @@ private static Set<String> getFilesChangedInCommit(String rawCommitInfo) {
  * Returns the file changed given a {@code rawFileChangedString}.
  */
  private static String getFileChanged(String rawFileChangedString) {
- String fileChanged = rawFileChangedString.split(TAB_SPLITTER)[STAT_FILE_PATH_INDEX].trim();
+ String fileChanged = StringsUtil.TAB.split(rawFileChangedString)[STAT_FILE_PATH_INDEX].trim();
  if (fileChanged.contains(MOVED_FILE_INDICATION)) {
  fileChanged = fileChanged.substring(fileChanged.indexOf(MOVED_FILE_INDICATION)
  + MOVED_FILE_INDICATION.length());