add optional executable to GraphvizCmdLineEngine (see #154)

Signed-off-by: Stefan Niederhauser <[email protected]>

Author: nidi3

graphviz-java/src/main/java/guru/nidi/graphviz/engine/GraphvizCmdLineEngine.java

@@ -29,6 +29,9 @@
 import java.util.concurrent.TimeUnit;
 
 import static guru.nidi.graphviz.engine.GraphvizLoader.isOnClasspath;
+import static guru.nidi.graphviz.service.CommandRunner.isExecutableFile;
+import static guru.nidi.graphviz.service.CommandRunner.isExecutableFound;
+import static guru.nidi.graphviz.service.SystemUtils.pathOf;
 import static java.util.Locale.ENGLISH;
 
 /**
@@ -40,6 +43,8 @@ public class GraphvizCmdLineEngine extends AbstractGraphvizEngine {
     private static final Logger LOG = LoggerFactory.getLogger(AbstractGraphvizEngine.class);
     static final boolean AVAILABLE = isOnClasspath("org/apache/commons/exec/CommandLine.class");
 
+    @Nullable
+    private final String executable;
     private final String envPath;
     private final CommandRunner cmdRunner;
 
@@ -49,13 +54,30 @@ public class GraphvizCmdLineEngine extends AbstractGraphvizEngine {
     private String outputFileName;
 
     public GraphvizCmdLineEngine() {
-        this(Optional.ofNullable(System.getenv("PATH")).orElse(""), defaultExecutor());
+        this(null, Optional.ofNullable(System.getenv("PATH")).orElse(""), runner(defaultExecutor()));
+    }
+
+    public GraphvizCmdLineEngine(String executable) {
+        this(executable, Optional.ofNullable(System.getenv("PATH")).orElse(""), runner(defaultExecutor()));
     }
 
-    public GraphvizCmdLineEngine(String envPath, CommandLineExecutor executor) {
+    private GraphvizCmdLineEngine(@Nullable String executable, String envPath, CommandRunner cmdRunner) {
         super(true);
+        this.executable = executable;
         this.envPath = envPath;
-        cmdRunner = new CommandBuilder()
+        this.cmdRunner = cmdRunner;
+    }
+
+    public GraphvizCmdLineEngine searchPath(String path) {
+        return new GraphvizCmdLineEngine(executable, path, cmdRunner);
+    }
+
+    public GraphvizCmdLineEngine executor(CommandLineExecutor executor) {
+        return new GraphvizCmdLineEngine(executable, envPath, runner(executor));
+    }
+
+    private static CommandRunner runner(CommandLineExecutor executor) {
+        return new CommandBuilder()
                 .withShellWrapper(true)
                 .withCommandExecutor(executor)
                 .build();
@@ -76,7 +98,7 @@ public GraphvizCmdLineEngine timeout(int amount, TimeUnit unit) {
 
     @Override
     protected void doInit() {
-        getEngineExecutable(Engine.DOT);
+        getEngineExecutable();
     }
 
     @Override
@@ -96,10 +118,10 @@ public EngineResult execute(String src, Options options, Rasterizer rasterizer)
 
     private EngineResult doExecute(Path path, File dotFile, Options options, Rasterizer rasterizer)
             throws IOException, InterruptedException {
-        final String engine = getEngineExecutable(options.engine);
         final String format = getFormatName(options.format, rasterizer);
-        final String command = engine
+        final String command = getEngineExecutable()
                 + (options.yInvert != null && options.yInvert ? " -y" : "")
+                + " -K" + options.engine.toString().toLowerCase(ENGLISH)
                 + " -T" + format
                 + " " + dotFile.getAbsolutePath() + " -ooutfile." + format;
         cmdRunner.exec(command, path.toFile(), timeout);
@@ -116,11 +138,16 @@ protected String preprocessCode(String src, Options options) {
         return replacePaths(imgReplaced, IMAGE_ATTR, path -> replacePath(path, options.basedir));
     }
 
-    private String getEngineExecutable(@Nullable Engine engine) {
-        final String cmd = engine == null ? "dot" : engine.toString().toLowerCase(ENGLISH);
-        final List<String> exes = SystemUtils.executableNames(cmd);
+    private String getEngineExecutable() {
+        if (executable != null) {
+            if (isExecutableFile(pathOf(executable)) || isExecutableFound(executable, envPath)) {
+                return executable;
+            }
+            LOG.warn("Executable '" + executable + "' not found directly and not on PATH. Trying with 'dot'.");
+        }
+        final List<String> exes = SystemUtils.executableNames("dot");
         for (final String exe : exes) {
-            if (CommandRunner.isExecutableFound(exe, envPath)) {
+            if (isExecutableFound(exe, envPath)) {
                 return exe;
             }
         }

graphviz-java/src/main/java/guru/nidi/graphviz/service/CommandRunner.java

@@ -26,9 +26,11 @@
 import java.nio.file.Path;
 import java.util.*;
 import java.util.function.Function;
-import java.util.stream.Collectors;
 import java.util.stream.Stream;
 
+import static guru.nidi.graphviz.service.SystemUtils.fileNameEquals;
+import static java.util.stream.Collectors.toList;
+
 public class CommandRunner {
     private static final Logger LOG = LoggerFactory.getLogger(CommandRunner.class);
 
@@ -68,7 +70,6 @@ void exec(CommandLine cmd, @Nullable File workDir, int timeout) throws IOExcepti
         cmdExec.execute(wrappedCmd, workDir, timeout);
     }
 
-    // Cross-platform way of finding an executable in the $PATH.
     static Stream<Path> which(String program) {
         return which(program, Optional.ofNullable(System.getenv("PATH")).orElse(""));
     }
@@ -85,19 +86,9 @@ private static Stream<Path> which(@Nullable String optProgram, @Nullable String
                 .map(path -> {
                     try (Stream<Path> entries = Files.list(path)) {
                         return entries
-                                // Filter on the filename
-                                // Doing a case-sensitive compare here, that's not correct on windows ?
-                                .filter(filePath -> program.equals(filePath.getFileName().toString()))
-
-                                // Filter out folders
-                                .filter(filePath -> Files.isRegularFile(filePath))
-
-                                // Check if the file is executable
-                                // Does this check work on Windows this way ?
-                                .filter(Files::isExecutable)
-
-                                // Consume the stream here - we're inside a try-with-resources
-                                .collect(Collectors.toList())
+                                .filter(filePath -> fileNameEquals(program, filePath.getFileName().toString()))
+                                .filter(CommandRunner::isExecutableFile)
+                                .collect(toList())
                                 .stream();
                     } catch (IOException e) {
                         LOG.error("Problem finding path for {}", program, e);
@@ -107,6 +98,10 @@ private static Stream<Path> which(@Nullable String optProgram, @Nullable String
                 .flatMap(stream -> stream);
     }
 
+    public static boolean isExecutableFile(Path path) {
+        return Files.isRegularFile(path) && Files.isExecutable(path); //TODO Does this check work on Windows this way ?
+    }
+
     static boolean isExecutableFound(String program) {
         return which(program).anyMatch(path -> true);
     }

graphviz-java/src/main/java/guru/nidi/graphviz/service/SystemUtils.java

@@ -83,6 +83,10 @@ public static List<String> executableNames(String filename) {
                 : singletonList(filename);
     }
 
+    public static boolean fileNameEquals(String file1, String file2) {
+        return IS_OS_WINDOWS ? file1.equalsIgnoreCase(file2) : file1.equals(file2);
+    }
+
     public static Function<CommandLine, CommandLine> getShellWrapperOrDefault(boolean shellWrapper) {
         if (!shellWrapper) {
             return Function.identity();

graphviz-java/src/test/java/guru/nidi/graphviz/engine/EngineTest.java

@@ -154,11 +154,9 @@ static List<Supplier<GraphvizEngine>> multi() {
 
     @Test
     void cmdLine() throws IOException, InterruptedException {
-        final File dotFile = setUpFakeDotFile();
-        final CommandLineExecutor cmdExecutor = setUpFakeStubCommandExecutor();
-
-        final String envPath = dotFile.getParent();
-        Graphviz.useEngine(new GraphvizCmdLineEngine(envPath, cmdExecutor));
+        Graphviz.useEngine(new GraphvizCmdLineEngine("dot")
+                .searchPath(setUpFakeDotFile().getParent())
+                .executor(setUpFakeStubCommandExecutor()));
 
         final String actual = Graphviz.fromString("graph g {a--b}").render(SVG_STANDALONE).toString();
         assertThat(actual, startsWith(START1_7.replace("\n", System.lineSeparator())));
@@ -169,17 +167,14 @@ void cmdLine() throws IOException, InterruptedException {
      */
     @Test
     void cmdLineOutputDotFile() throws IOException, InterruptedException {
-        final File dotFile = setUpFakeDotFile();
-        final CommandLineExecutor cmdExecutor = setUpFakeStubCommandExecutor();
-
-        final String envPath = dotFile.getParent();
-
         final File dotOutputFolder = new File(temp, "out");
         dotOutputFolder.mkdir();
         final String dotOutputName = "test123";
 
         // Configure engine to output the dotFile to dotOutputFolder
-        final GraphvizCmdLineEngine engine = new GraphvizCmdLineEngine(envPath, cmdExecutor);
+        final GraphvizCmdLineEngine engine = new GraphvizCmdLineEngine()
+                .searchPath(setUpFakeDotFile().getParent())
+                .executor(setUpFakeStubCommandExecutor());
         engine.setDotOutputFile(dotOutputFolder.getAbsolutePath(), dotOutputName);
 
         Graphviz.useEngine(engine);