feat: new HTTP API for the Git like model data structure

The previous API was just a dumb key value store where the
model server didn't understand the data that is stored.
The new API allows the server to work closer together with
the client to improve the performance and consistency.

Author: slisson

model-api/src/commonMain/kotlin/org/modelix/model/api/PNodeAdapter.kt

@@ -153,7 +153,7 @@ open class PNodeAdapter(val nodeId: Long, val branch: IBranch) : INode {
     }
 
     override fun getReferenceRoles(): List<String> {
-        return branch.transaction.getPropertyRoles(nodeId).toList()
+        return branch.transaction.getReferenceRoles(nodeId).toList()
     }
 
     override fun equals(o: Any?): Boolean {
@@ -205,3 +205,6 @@ open class PNodeAdapter(val nodeId: Long, val branch: IBranch) : INode {
         notifyAccess()
     }
 }
+
+fun IBranch.getNode(id: Long): INode = PNodeAdapter(id, this)
+fun IBranch.getRootNode(): INode = getNode(ITree.ROOT_ID)

model-api/src/commonMain/kotlin/org/modelix/model/data/ModelData.kt

@@ -74,3 +74,16 @@ fun NodeData.uid(model: ModelData): String {
         (id ?: throw IllegalArgumentException("Node has no ID"))
 }
 fun ModelData.nodeUID(node: NodeData): String = node.uid(this)
+
+fun INode.asData(): NodeData = NodeData(
+    id = reference.serialize(),
+    concept = concept?.getUID(),
+    role = roleInParent,
+    properties = getPropertyRoles().associateWithNotNull { getPropertyValue(it) },
+    references = getReferenceRoles().associateWithNotNull { getReferenceTargetRef(it)?.serialize() },
+    children = allChildren.map { it.asData() }
+)
+
+public inline fun <K, V : Any> Iterable<K>.associateWithNotNull(valueSelector: (K) -> V?): Map<K, V> {
+    return associateWith { valueSelector(it) }.filterValues { it != null } as Map<K, V>
+}

model-client/build.gradle.kts

@@ -34,6 +34,7 @@ tasks.named("check") {
 val kotlinCoroutinesVersion: String by rootProject
 val kotlinLoggingVersion: String by rootProject
 val ktorVersion: String by rootProject
+val kotlinxSerializationVersion: String by rootProject
 
 kotlin {
     jvm()
@@ -51,11 +52,16 @@ kotlin {
         val commonMain by getting {
             dependencies {
                 api(project(":model-api"))
+                implementation(project(":model-server-api"))
                 kotlin("stdlib-common")
                 implementation("org.jetbrains.kotlinx:kotlinx-collections-immutable:0.3.4")
                 implementation("org.jetbrains.kotlinx:kotlinx-coroutines-core:$kotlinCoroutinesVersion")
                 implementation("io.github.microutils:kotlin-logging:$kotlinLoggingVersion")
                 implementation("org.jetbrains.kotlinx:kotlinx-datetime:0.4.0")
+                implementation("org.jetbrains.kotlinx:kotlinx-serialization-json:$kotlinxSerializationVersion")
+                implementation("io.ktor:ktor-client-core:$ktorVersion")
+                implementation("io.ktor:ktor-client-content-negotiation:$ktorVersion")
+                implementation("io.ktor:ktor-serialization-kotlinx-json:$ktorVersion")
             }
         }
         val commonTest by getting {

model-client/src/commonMain/kotlin/org/modelix/model/IVersion.kt

@@ -0,0 +1,21 @@
+/*
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.modelix.model
+
+import org.modelix.model.api.ITree
+
+interface IVersion {
+    fun getShaHash(): String
+    fun getTree(): ITree
+}

model-client/src/commonMain/kotlin/org/modelix/model/client2/IModelClientV2.kt

@@ -0,0 +1,45 @@
+/*
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.modelix.model.client2
+
+import org.modelix.model.IVersion
+import org.modelix.model.api.IIdGenerator
+import org.modelix.model.lazy.BranchReference
+import org.modelix.model.lazy.RepositoryId
+import org.modelix.model.server.api.ModelQuery
+
+interface IModelClientV2 {
+    fun getClientId(): Int
+    fun getIdGenerator(): IIdGenerator
+    fun getUserId(): String?
+
+    suspend fun initRepository(repository: RepositoryId): IVersion
+    suspend fun listRepositories(): List<RepositoryId>
+
+    suspend fun listBranches(repository: RepositoryId): List<BranchReference>
+
+    suspend fun loadVersion(versionHash: String, baseVersion: IVersion?): IVersion
+
+    /**
+     * The pushed version is merged automatically by the server with the current head.
+     * The merge result is returned.
+     */
+    suspend fun push(branch: BranchReference, version: IVersion): IVersion
+
+    suspend fun pull(branch: BranchReference, lastKnownVersion: IVersion?): IVersion
+    suspend fun pull(branch: BranchReference, lastKnownVersion: IVersion?, filter: ModelQuery): IVersion
+
+    suspend fun poll(branch: BranchReference, lastKnownVersion: IVersion?): IVersion
+    suspend fun poll(branch: BranchReference, lastKnownVersion: IVersion?, filter: ModelQuery): IVersion
+}