Implement caching for diff in IntelliJ extension

extensions/intellij/src/main/kotlin/com/github/continuedev/continueintellijextension/activities/ContinuePluginStartupActivity.kt

@@ -1,4 +1,5 @@
 package com.github.continuedev.continueintellijextension.activities
+import IntelliJIDE
 import com.intellij.openapi.fileEditor.FileEditorManagerListener
 import com.github.continuedev.continueintellijextension.auth.AuthListener
 import com.github.continuedev.continueintellijextension.auth.ContinueAuthService
@@ -185,6 +186,8 @@ class ContinuePluginStartupActivity : StartupActivity, DumbAware {
 
                     // Notify core of content changes
                     if (changedURIs.isNotEmpty()) {
+                        continuePluginService.updateLastFileSaveTimestamp()
+
                         val data = mapOf("uris" to changedURIs)
                         continuePluginService.coreMessenger?.request("files/changed", data, null) { _ -> }
                     }

extensions/intellij/src/main/kotlin/com/github/continuedev/continueintellijextension/continue/GitService.kt

@@ -0,0 +1,94 @@
+package com.github.continuedev.continueintellijextension.`continue`
+
+import com.github.continuedev.continueintellijextension.services.ContinuePluginService
+import com.github.continuedev.continueintellijextension.utils.toUriOrNull
+import com.intellij.openapi.project.Project
+import com.intellij.openapi.project.guessProjectDir
+import kotlinx.coroutines.Dispatchers
+import kotlinx.coroutines.withContext
+import java.io.BufferedReader
+import java.io.File
+import java.io.InputStreamReader
+import java.net.URI
+
+class GitService(
+    private val project: Project,
+    private val continuePluginService: ContinuePluginService
+) {
+    // Add a simple cache for diff results
+    private data class DiffCache(
+        val timestamp: Long,
+        val diffs: List<String>
+    )
+
+    // Cache the last diff result
+    private var diffCache: DiffCache? = null
+    private var lastFileSaveTimestamp: Long = System.currentTimeMillis()
+
+    /**
+     * Updates the timestamp when a file is saved
+     */
+    fun updateLastFileSaveTimestamp() {
+        lastFileSaveTimestamp = System.currentTimeMillis()
+    }
+
+    /**
+     * Returns the git diff for all workspace directories
+     */
+    suspend fun getDiff(includeUnstaged: Boolean): List<String> {
+        // Check if we have a valid cache entry
+        if (diffCache != null && diffCache!!.timestamp == lastFileSaveTimestamp) {
+            return diffCache!!.diffs
+        }
+
+        // If no cache hit, compute the diff
+        val workspaceDirs = workspaceDirectories()
+        val diffs = mutableListOf<String>()
+
+        for (workspaceDir in workspaceDirs) {
+            val output = StringBuilder()
+            val builder = if (includeUnstaged) {
+                ProcessBuilder("git", "diff")
+            } else {
+                ProcessBuilder("git", "diff", "--cached")
+            }
+            builder.directory(File(URI(workspaceDir)))
+            val process = withContext(Dispatchers.IO) {
+                builder.start()
+            }
+
+            val reader = BufferedReader(InputStreamReader(process.inputStream))
+            var line: String? = withContext(Dispatchers.IO) {
+                reader.readLine()
+            }
+            while (line != null) {
+                output.append(line)
+                output.append("\n")
+                line = withContext(Dispatchers.IO) {
+                    reader.readLine()
+                }
+            }
+
+            withContext(Dispatchers.IO) {
+                process.waitFor()
+            }
+
+            diffs.add(output.toString())
+        }
+
+        // Cache the result
+        diffCache = DiffCache(lastFileSaveTimestamp, diffs)
+        return diffs
+    }
+
+    private fun workspaceDirectories(): Array<String> {
+        val dirs = this.continuePluginService.workspacePaths
+
+        if (dirs?.isNotEmpty() == true) {
+            return dirs
+        }
+
+        return listOfNotNull(project.guessProjectDir()?.toUriOrNull()).toTypedArray()
+    }
+
+}

extensions/intellij/src/main/kotlin/com/github/continuedev/continueintellijextension/continue/IdeProtocolClient.kt

@@ -45,6 +45,10 @@ class IdeProtocolClient(
         )
     }
 
+    fun updateLastFileSaveTimestamp() {
+        (ide as IntelliJIDE).updateLastFileSaveTimestamp()
+    }
+
     fun handleMessage(msg: String, respond: (Any?) -> Unit) {
         coroutineScope.launch(Dispatchers.IO) {
             val message = Gson().fromJson(msg, Message::class.java)

extensions/intellij/src/main/kotlin/com/github/continuedev/continueintellijextension/continue/IntelliJIde.kt

@@ -1,13 +1,9 @@
 import com.github.continuedev.continueintellijextension.*
 import com.github.continuedev.continueintellijextension.constants.getContinueGlobalPath
+import com.github.continuedev.continueintellijextension.`continue`.GitService
 import com.github.continuedev.continueintellijextension.services.ContinueExtensionSettings
 import com.github.continuedev.continueintellijextension.services.ContinuePluginService
-import com.github.continuedev.continueintellijextension.utils.OS
-import com.github.continuedev.continueintellijextension.utils.getMachineUniqueID
-import com.github.continuedev.continueintellijextension.utils.getOS
-import com.github.continuedev.continueintellijextension.utils.toUriOrNull
-import com.github.continuedev.continueintellijextension.utils.Desktop
-import com.google.gson.Gson
+import com.github.continuedev.continueintellijextension.utils.*
 import com.intellij.codeInsight.daemon.impl.HighlightInfo
 import com.intellij.execution.configurations.GeneralCommandLine
 import com.intellij.execution.util.ExecUtil
@@ -31,28 +27,26 @@ import com.intellij.openapi.vfs.LocalFileSystem
 import com.intellij.openapi.vfs.VirtualFileManager
 import com.intellij.psi.PsiDocumentManager
 import com.intellij.testFramework.LightVirtualFile
-import com.intellij.util.containers.toArray
 import kotlinx.coroutines.*
-import okhttp3.MediaType.Companion.toMediaType
-import okhttp3.OkHttpClient
-import okhttp3.Request
-import okhttp3.RequestBody.Companion.toRequestBody
 import java.awt.Toolkit
 import java.awt.datatransfer.DataFlavor
 import java.io.BufferedReader
 import java.io.File
 import java.io.FileInputStream
 import java.io.InputStreamReader
 import java.net.URI
-import java.net.URL
 import java.nio.charset.Charset
 import java.nio.file.Paths
 
 class IntelliJIDE(
     private val project: Project,
     private val continuePluginService: ContinuePluginService,
 
-    ) : IDE {
+) : IDE {
+
+    private val gitService = GitService(project, continuePluginService)
+
+
     private val ripgrep: String
 
     init {
@@ -66,6 +60,13 @@ class IntelliJIDE(
             Paths.get(pluginPath.toString(), "ripgrep", "bin", "rg" + if (os == OS.WINDOWS) ".exe" else "").toString()
     }
 
+    /**
+     * Updates the timestamp when a file is saved
+     */
+    override fun updateLastFileSaveTimestamp() {
+        gitService.updateLastFileSaveTimestamp()
+    }
+
     override suspend fun getIdeInfo(): IdeInfo {
         val applicationInfo = ApplicationInfo.getInstance()
         val ideName: String = applicationInfo.fullApplicationName
@@ -110,41 +111,7 @@ class IntelliJIDE(
     }
 
     override suspend fun getDiff(includeUnstaged: Boolean): List<String> {
-        val workspaceDirs = workspaceDirectories()
-        val diffs = mutableListOf<String>()
-
-        for (workspaceDir in workspaceDirs) {
-            val output = StringBuilder()
-            val builder = if (includeUnstaged) {
-                ProcessBuilder("git", "diff")
-            } else {
-                ProcessBuilder("git", "diff", "--cached")
-            }
-            builder.directory(File(URI(workspaceDir)))
-            val process = withContext(Dispatchers.IO) {
-                builder.start()
-            }
-
-            val reader = BufferedReader(InputStreamReader(process.inputStream))
-            var line: String? = withContext(Dispatchers.IO) {
-                reader.readLine()
-            }
-            while (line != null) {
-                output.append(line)
-                output.append("\n")
-                line = withContext(Dispatchers.IO) {
-                    reader.readLine()
-                }
-            }
-
-            withContext(Dispatchers.IO) {
-                process.waitFor()
-            }
-
-            diffs.add(output.toString())
-        }
-
-        return diffs
+        return gitService.getDiff(includeUnstaged)
     }
 
     override suspend fun getClipboardContent(): Map<String, String> {
@@ -185,7 +152,7 @@ class IntelliJIDE(
     }
 
     override suspend fun getWorkspaceConfigs(): List<ContinueRcJson> {
-        val workspaceDirs = workspaceDirectories()
+        val workspaceDirs = this.getWorkspaceDirs()
 
         val configs = mutableListOf<String>()
 
@@ -434,7 +401,7 @@ class IntelliJIDE(
     }
 
     override suspend fun getTags(artifactId: String): List<IndexTag> {
-        val workspaceDirs = workspaceDirectories()
+        val workspaceDirs = this.getWorkspaceDirs()
 
         // Collect branches concurrently using Kotlin coroutines
         val branches = withContext(Dispatchers.IO) {
@@ -577,4 +544,5 @@ class IntelliJIDE(
 
         return listOfNotNull(project.guessProjectDir()?.toUriOrNull()).toTypedArray()
     }
+
 }

extensions/intellij/src/main/kotlin/com/github/continuedev/continueintellijextension/services/ContinuePluginService.kt

@@ -41,4 +41,8 @@ class ContinuePluginService : Disposable, DumbAware {
     ) {
         continuePluginWindow?.browser?.sendToWebview(messageType, data, messageId)
     }
+
+    fun updateLastFileSaveTimestamp() {
+        ideProtocolClient?.updateLastFileSaveTimestamp()
+    }
 }

extensions/intellij/src/main/kotlin/com/github/continuedev/continueintellijextension/types.kt

@@ -192,6 +192,10 @@ interface IDE {
 
     // Callbacks
     fun onDidChangeActiveTextEditor(callback: (filepath: String) -> Unit)
+
+    fun updateLastFileSaveTimestamp() {
+        // Default implementation does nothing
+    }
 }
 
 data class GetGhTokenArgs(