README.md

@@ -10,26 +10,6 @@ The package is named `tinyvm` for 'tiny version manager'.
 Since this is an internship application project, I have assumed that a minimal usage of external libraries is preferred,
 so that a greater technical understanding can be demonstrated.
 
-## Usage
-
-### Gradle
-```kotlin
-repositories {
-    // other repositories
-    maven { url "https://git.koval.net/api/packages/cyclane/maven" }
-}
-
-dependencies {
-    // other dependencies
-    implementation("net.koval.teamcity-gitea-test-task:tinyvm:0.1.1")
-}
-```
-
-### Documentation
-Use autocompletion and hover menus in your IDE, or download the
-generated HTML documentation
-from the [latest release](https://git.koval.net/cyclane/teamcity-gitea-test-task/releases).
-
 ## Instructions
 
 Create a library that implements simple Git functionality. You need to implement at least three entities:

src/main/kotlin/tinyvm/Commit.kt

@@ -1,6 +1,22 @@
 package tinyvm
 
+import java.security.MessageDigest
 import java.time.Instant
+import java.util.HexFormat
+
+/**
+ * Represents an arbitrary version manager object.
+ */
+abstract class Object(val type: String) {
+    abstract val data: String
+
+    fun hash(): String =
+        HexFormat.of().formatHex(
+            MessageDigest
+                .getInstance("SHA-1")
+                .digest("$type ${data.length}\u0000$data".toByteArray()),
+        )
+}
 
 /**
  * Commits are a pointer to a 'head' tree with some metadata.
@@ -12,6 +28,7 @@ class Commit(
     val timestamp: Instant,
 ) : Object("commit") {
     override val data: String
+        // Use \n\n for end of header in-case additional metadata is implemented in the future.
         get() = "tree ${tree.hash()}\nauthor $author\ntimestamp ${timestamp.epochSecond}\n\n$message"
 
     override fun toString(): String = "commit ${hash()}\n$data"

src/main/kotlin/tinyvm/Object.kt

@@ -1,17 +0,0 @@
-package tinyvm
-
-import java.security.MessageDigest
-import java.util.HexFormat
-
-/**
- * Represents an arbitrary version manager object.
- */
-abstract class Object(val type: String) {
-    abstract val data: String
-
-    fun hash(): String =
-        HexFormat.of().formatHex(
-            MessageDigest.getInstance("SHA-1")
-                .digest("$type ${data.length}\u0000$data".toByteArray()),
-        )
-}

src/main/kotlin/tinyvm/Repository.kt

@@ -1,59 +1,22 @@
 package tinyvm
 
-import java.util.TreeSet
-
 class HashCollisionException(hash: String) : Exception("Different object types with identical hash '$hash'")
 
-private class CommitTimeComparator : Comparator<Commit> {
+class CommitTimeComparator : Comparator<Commit> {
     override fun compare(
         o1: Commit,
         o2: Commit,
     ): Int = (o1.timestamp.epochSecond - o2.timestamp.epochSecond).toInt()
 }
 
-private val commitTimeComparator = CommitTimeComparator()
+class Repository {
-
+    private val commits = sortedSetOf(CommitTimeComparator())
-private class Branch(val name: String, val commits: TreeSet<Commit>)
-
-class Repository(initialBranch: String = "master") {
-    private var head = Branch(initialBranch, sortedSetOf(commitTimeComparator))
-    private val commits = mutableMapOf(initialBranch to head)
-
-    val branch: String
-        get() = head.name
-
-    val branches: Set<String>
-        get() = commits.keys
 
     // Store all objects in one map like git does. This would simplify the data persistence implementation (if there was
     // one) and allows for other objects to be added in the future without modifying the data persistence implementation
     // at all.
     private val objects = mutableMapOf<String, Object>()
 
-    /**
-     * Create a new branch as a copy of the current branch.
-     * @param name New branch name.
-     * @param use Whether to switch to this branch.
-     */
-    fun createBranch(
-        name: String,
-        use: Boolean = true,
-    ) {
-        commits[name] =
-            Branch(
-                name,
-                head.commits.clone() as? TreeSet<Commit> ?: throw Exception("TreeSet.clone() unexpected result"),
-            )
-        if (use) useBranch(name)
-    }
-
-    /**
-     * Use (switch to) a branch.
-     */
-    fun useBranch(name: String) {
-        head = commits[name] ?: throw BranchNotFoundException(name)
-    }
-
     /**
      * (Deep) get or put a commit object into the repository.
      * This will also get or put all child trees and blobs.
@@ -70,7 +33,7 @@ class Repository(initialBranch: String = "master") {
                 timestamp = commit.timestamp,
             )
         objects[hash] = newCommit
-        head.commits.add(newCommit)
+        commits.add(newCommit)
         return newCommit
     }
 
@@ -82,12 +45,12 @@ class Repository(initialBranch: String = "master") {
     /**
      * List all commits.
      */
-    fun listCommits(): List<Commit> = head.commits.toList()
+    fun listCommits(): List<Commit> = commits.toList()
 
     /**
      * Find commit.
      */
-    fun findCommit(predicate: (Commit) -> Boolean): Commit? = head.commits.find(predicate)
+    fun findCommit(predicate: (Commit) -> Boolean): Commit? = commits.find(predicate)
 
     /**
      * Dump repository objects
@@ -127,5 +90,3 @@ class Repository(initialBranch: String = "master") {
     private inline fun <reified T : Object> findObject(hash: String): T? =
         objects[hash]?.let { it as? T ?: throw HashCollisionException(hash) }
 }
-
-class BranchNotFoundException(name: String) : Exception("Branch '$name' does not exist")

src/main/kotlin/tinyvm/Tree.kt

@@ -15,22 +15,9 @@ class Tree(val nodes: Map<String, Node>) : Node("tree") {
             nodes.map { (name, node) ->
                 "${node.type} $name\u0000${node.hash()}"
             }.sorted().joinToString()
-
-    override fun toString(): String =
-        "tree ${hash()}\n" +
-            nodes.map { (name, node) ->
-                when (node) {
-                    is Tree -> "+$name/\n"
-                    is Blob -> "+$name\n"
-                } + node.toString().insertLeftMargin()
-            }.sorted().joinToString("\n")
 }
 
 /**
  * A blob is a data container.
  */
-class Blob(override val data: String) : Node("blob") {
+class Blob(override val data: String) : Node("blob")
-    override fun toString(): String = "blob ${hash()}\n${data.insertLeftMargin()}"
-}
-
-private fun String.insertLeftMargin(): String = split('\n').joinToString("\n") { "| $it" }

src/test/kotlin/tinyvm/RepositoryTest.kt

@@ -1,6 +1,5 @@
 package tinyvm
 
-import org.junit.jupiter.api.assertThrows
 import java.time.Instant
 import kotlin.test.Test
 import kotlin.test.assertEquals
@@ -19,22 +18,22 @@ internal class RepositoryTest {
                 tree =
                     Tree(
                         mapOf(
-                            "dir2" to
-                                Tree(
-                                    mapOf(
-                                        "test1.txt" to Blob("This is a second file"),
-                                    ),
-                                ),
                             "dir1" to
                                 Tree(
                                     mapOf(
                                         "test1.txt" to Blob("Hello World!"),
                                     ),
                                 ),
+                            "dir2" to
+                                Tree(
+                                    mapOf(
+                                        "test2.txt" to Blob("This is a second file"),
+                                    ),
+                                ),
                         ),
                     ),
                 author = Author("Gleb Koval", "gleb@koval.net"),
-                message = "Move test1.txt to dir1 and add dir2/test1.txt",
+                message = "Move test1.txt and add dir2/test2.txt",
                 timestamp = Instant.ofEpochSecond(50),
             ),
             Commit(
@@ -50,7 +49,7 @@ internal class RepositoryTest {
                             "dir2" to
                                 Tree(
                                     mapOf(
-                                        "test1.txt" to Blob("This is a second file"),
+                                        "test2.txt" to Blob("This is a second file"),
                                     ),
                                 ),
                             "README.md" to Blob("# This is a test repo!"),
@@ -118,75 +117,4 @@ internal class RepositoryTest {
         assertEquals(committed, repository.findCommit { it.message.matches("Move.*".toRegex()) })
         assertEquals(null, repository.getCommit("00000000000000000000"))
     }
-
-    @Test
-    fun `can create and use branch`() {
-        repository.commit(commits[0])
-        repository.commit(commits[1])
-        repository.commit(commits[2])
-        repository.createBranch("test-branch", use = false)
-        assertEquals("master", repository.branch)
-        repository.createBranch("test-branch-2")
-        assertEquals("test-branch-2", repository.branch)
-        assertEquals(setOf("master", "test-branch", "test-branch-2"), repository.branches)
-        assertEquals(commits.map { it.hash() }, repository.listCommits().map { it.hash() })
-        assertEquals(10, repository.dumpObjects().size)
-    }
-
-    @Test
-    fun `cannot use non-existent branch`() {
-        assertThrows<BranchNotFoundException> {
-            repository.useBranch("test-branch")
-        }
-    }
-
-    @Test
-    fun `can commit to branch`() {
-        repository.commit(commits[0])
-        repository.createBranch("test-branch")
-        repository.commit(commits[1])
-        repository.createBranch("test-branch-2")
-        repository.commit(commits[2])
-
-        assertEquals(commits.map { it.hash() }, repository.listCommits().map { it.hash() })
-        repository.useBranch("test-branch")
-        assertEquals(commits.take(2).map { it.hash() }, repository.listCommits().map { it.hash() })
-        repository.useBranch("master")
-        assertEquals(commits.take(1).map { it.hash() }, repository.listCommits().map { it.hash() })
-    }
-
-    @Test
-    fun `can display commit`() {
-        assertEquals(
-            """
-            commit 804c6f0c66da0ea0eab8ac29f23a627e03a962b2
-            tree aaebbb258bce30749fc302cbd161b78462252a32
-            author Gleb Koval <gleb@koval.net>
-            timestamp 0
-            
-            Add test1.txt
-            """.trimIndent(),
-            commits[0].toString(),
-        )
-    }
-
-    @Test
-    fun `can display tree`() {
-        assertEquals(
-            """
-            tree 048b8e267dd7a6c5d4849d59f6ff82e6ae948f13
-            +dir1/
-            | tree aaebbb258bce30749fc302cbd161b78462252a32
-            | +test1.txt
-            | | blob c57eff55ebc0c54973903af5f72bac72762cf4f4
-            | | | Hello World!
-            +dir2/
-            | tree 0e14cbdba02924cd63a58c2492fc3dd05dc682bd
-            | +test1.txt
-            | | blob da3fcc31cbc16fcbb7526d68771f77e7e7f02fb1
-            | | | This is a second file
-            """.trimIndent(),
-            commits[1].tree.toString(),
-        )
-    }
 }