This commit is contained in:
Gleb Koval 2023-12-01 20:16:08 +00:00
parent 6c948c9630
commit d5deef82c1
Signed by: cyclane
GPG Key ID: 15E168A8B332382C
6 changed files with 87 additions and 74 deletions

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@ -5,6 +5,7 @@
<option name="linkedExternalProjectsSettings"> <option name="linkedExternalProjectsSettings">
<GradleProjectSettings> <GradleProjectSettings>
<option name="externalProjectPath" value="$PROJECT_DIR$" /> <option name="externalProjectPath" value="$PROJECT_DIR$" />
<option name="gradleJvm" value="corretto-19" />
<option name="modules"> <option name="modules">
<set> <set>
<option value="$PROJECT_DIR$" /> <option value="$PROJECT_DIR$" />

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@ -7,7 +7,9 @@ abstract class Object(
val type: String, val type: String,
) { ) {
abstract val data: String abstract val data: String
fun hash(): String = MessageDigest
fun hash(): String =
MessageDigest
.getInstance("SHA-1") .getInstance("SHA-1")
.digest("$type ${data.length}\u0000$data".toByteArray()) .digest("$type ${data.length}\u0000$data".toByteArray())
.toHex() .toHex()
@ -17,7 +19,7 @@ class Commit(
val tree: Tree, val tree: Tree,
val author: Author, val author: Author,
val message: String, val message: String,
val timestamp: Instant val timestamp: Instant,
) : Object("commit") { ) : Object("commit") {
// Use \n\n for end of header in-case additional metadata is implemented in the future. // Use \n\n for end of header in-case additional metadata is implemented in the future.
override val data: String override val data: String
@ -26,8 +28,7 @@ class Commit(
data class Author( data class Author(
val name: String, val name: String,
val email: String val email: String,
) { ) {
override fun toString(): String = override fun toString(): String = "$name <$email>"
"$name <$email>"
} }

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@ -2,5 +2,4 @@ package tinyvm
import java.util.HexFormat import java.util.HexFormat
fun ByteArray.toHex(): String = fun ByteArray.toHex(): String = HexFormat.of().formatHex(this)
HexFormat.of().formatHex(this)

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@ -3,8 +3,10 @@ package tinyvm
class HashCollisionException(hash: String) : Exception("Different object types with identical hash '$hash'") class HashCollisionException(hash: String) : Exception("Different object types with identical hash '$hash'")
class CommitTimeComparator : Comparator<Commit> { class CommitTimeComparator : Comparator<Commit> {
override fun compare(o1: Commit, o2: Commit): Int = override fun compare(
(o1.timestamp.epochSecond - o2.timestamp.epochSecond).toInt() o1: Commit,
o2: Commit,
): Int = (o1.timestamp.epochSecond - o2.timestamp.epochSecond).toInt()
} }
class Repository { class Repository {
@ -23,11 +25,12 @@ class Repository {
val hash = commit.hash() val hash = commit.hash()
val obj = findObject<Commit>(hash) val obj = findObject<Commit>(hash)
if (obj != null) return obj if (obj != null) return obj
val newCommit = Commit( val newCommit =
Commit(
tree = addTree(commit.tree), tree = addTree(commit.tree),
author = commit.author, author = commit.author,
message = commit.message, message = commit.message,
timestamp = commit.timestamp timestamp = commit.timestamp,
) )
objects[hash] = newCommit objects[hash] = newCommit
commits.add(newCommit) commits.add(newCommit)
@ -47,8 +50,7 @@ class Repository {
/** /**
* Find commit. * Find commit.
*/ */
fun findCommit(predicate: (Commit) -> Boolean): Commit? = fun findCommit(predicate: (Commit) -> Boolean): Commit? = commits.find(predicate)
commits.find(predicate)
/** /**
* Dump repository objects * Dump repository objects
@ -63,13 +65,14 @@ class Repository {
val hash = tree.hash() val hash = tree.hash()
val obj = findObject<Tree>(hash) val obj = findObject<Tree>(hash)
if (obj != null) return obj if (obj != null) return obj
val newTree = Tree( val newTree =
Tree(
tree.nodes.map { (name, node) -> tree.nodes.map { (name, node) ->
when (node) { when (node) {
is Tree -> name to addTree(node) is Tree -> name to addTree(node)
is Blob -> name to addObject(node) is Blob -> name to addObject(node)
} }
}.toMap() }.toMap(),
) )
objects[hash] = newTree objects[hash] = newTree
return tree return tree
@ -86,5 +89,4 @@ class Repository {
*/ */
private inline fun <reified T : Object> findObject(hash: String): T? = private inline fun <reified T : Object> findObject(hash: String): T? =
objects[hash]?.let { it as? T ?: throw HashCollisionException(hash) } objects[hash]?.let { it as? T ?: throw HashCollisionException(hash) }
} }

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@ -5,7 +5,8 @@ sealed class Node(type: String): Object(type)
class Tree(val nodes: Map<String, Node>) : Node("tree") { class Tree(val nodes: Map<String, Node>) : Node("tree") {
// For simplicity just use the hex-formatted hash, not the actual value like git does. // For simplicity just use the hex-formatted hash, not the actual value like git does.
override val data: String override val data: String
get() = nodes.map { (name, node) -> get() =
nodes.map { (name, node) ->
"${node.type} $name\u0000${node.hash()}" "${node.type} $name\u0000${node.hash()}"
}.sorted().joinToString() }.sorted().joinToString()
} }

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@ -6,50 +6,59 @@ import kotlin.test.assertEquals
internal class RepositoryTest { internal class RepositoryTest {
private val repository = Repository() private val repository = Repository()
private val commits = listOf( private val commits =
listOf(
Commit( Commit(
tree = Tree(mapOf("test1.txt" to Blob("Hello World!"))), tree = Tree(mapOf("test1.txt" to Blob("Hello World!"))),
author = Author("Gleb Koval", "gleb@koval.net"), author = Author("Gleb Koval", "gleb@koval.net"),
message = "Add test1.txt", message = "Add test1.txt",
timestamp = Instant.ofEpochSecond(0) timestamp = Instant.ofEpochSecond(0),
), Commit(
tree = Tree(
mapOf(
"dir1" to Tree(
mapOf(
"test1.txt" to Blob("Hello World!")
)
), ),
"dir2" to Tree( Commit(
tree =
Tree(
mapOf( mapOf(
"test2.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"), author = Author("Gleb Koval", "gleb@koval.net"),
message = "Move test1.txt and add dir2/test2.txt", message = "Move test1.txt and add dir2/test2.txt",
timestamp = Instant.ofEpochSecond(50) timestamp = Instant.ofEpochSecond(50),
), Commit(
tree = Tree(
mapOf(
"dir1" to Tree(
mapOf(
"test1.txt" to Blob("Hello World!")
)
), ),
"dir2" to Tree( Commit(
tree =
Tree(
mapOf( mapOf(
"test2.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"),
),
),
"README.md" to Blob("# This is a test repo!"),
), ),
"README.md" to Blob("# This is a test repo!")
)
), ),
author = Author("Gleb Koval", "gleb@koval.net"), author = Author("Gleb Koval", "gleb@koval.net"),
message = "Add README.md", message = "Add README.md",
timestamp = Instant.ofEpochSecond(100) timestamp = Instant.ofEpochSecond(100),
) ),
) )
@Test @Test