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">
<GradleProjectSettings>
<option name="externalProjectPath" value="$PROJECT_DIR$" />
<option name="gradleJvm" value="corretto-19" />
<option name="modules">
<set>
<option value="$PROJECT_DIR$" />

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

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

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@ -2,9 +2,11 @@ package tinyvm
class HashCollisionException(hash: String) : Exception("Different object types with identical hash '$hash'")
class CommitTimeComparator: Comparator<Commit> {
override fun compare(o1: Commit, o2: Commit): Int =
(o1.timestamp.epochSecond - o2.timestamp.epochSecond).toInt()
class CommitTimeComparator : Comparator<Commit> {
override fun compare(
o1: Commit,
o2: Commit,
): Int = (o1.timestamp.epochSecond - o2.timestamp.epochSecond).toInt()
}
class Repository {
@ -23,11 +25,12 @@ class Repository {
val hash = commit.hash()
val obj = findObject<Commit>(hash)
if (obj != null) return obj
val newCommit = Commit(
val newCommit =
Commit(
tree = addTree(commit.tree),
author = commit.author,
message = commit.message,
timestamp = commit.timestamp
timestamp = commit.timestamp,
)
objects[hash] = newCommit
commits.add(newCommit)
@ -47,8 +50,7 @@ class Repository {
/**
* Find commit.
*/
fun findCommit(predicate: (Commit) -> Boolean): Commit? =
commits.find(predicate)
fun findCommit(predicate: (Commit) -> Boolean): Commit? = commits.find(predicate)
/**
* Dump repository objects
@ -63,13 +65,14 @@ class Repository {
val hash = tree.hash()
val obj = findObject<Tree>(hash)
if (obj != null) return obj
val newTree = Tree(
val newTree =
Tree(
tree.nodes.map { (name, node) ->
when (node) {
is Tree -> name to addTree(node)
is Blob -> name to addObject(node)
}
}.toMap()
}.toMap(),
)
objects[hash] = newTree
return tree
@ -86,5 +89,4 @@ class Repository {
*/
private inline fun <reified T : Object> findObject(hash: String): T? =
objects[hash]?.let { it as? T ?: throw HashCollisionException(hash) }
}

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@ -1,11 +1,12 @@
package tinyvm
sealed class Node(type: String): Object(type)
sealed class Node(type: String) : Object(type)
class Tree(val nodes: Map<String, Node>) : Node("tree") {
// For simplicity just use the hex-formatted hash, not the actual value like git does.
override val data: String
get() = nodes.map { (name, node) ->
get() =
nodes.map { (name, node) ->
"${node.type} $name\u0000${node.hash()}"
}.sorted().joinToString()
}

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