perf(app): fix composer lag via buffered blob draft storage

packages/app/src/components/prompt-input-v2.tsx

@@ -344,7 +344,7 @@ export function usePromptInputV2Controller(props: PromptInputV2ControllerProps):
       if (item?.commentID) comments.remove(item.path, item.commentID)
     },
     openAttachment: (attachment) =>
-      dialog.show(() => <ImagePreview src={attachment.dataUrl} alt={attachment.filename} />),
+      dialog.show(() => <ImagePreview src={attachment.blob.url} alt={attachment.filename} />),
     openContext(key) {
       const item = controller.contextItem(key)
       if (item) openComment(item, props, sync, layout, files, comments)
@@ -377,6 +377,7 @@ export function usePromptInputV2Controller(props: PromptInputV2ControllerProps):
         }),
       readClipboardImage: platform.readClipboardImage,
       getPathForFile: platform.getPathForFile,
+      store: platform.draftStore?.putBlob,
     },
     view: {
       placeholder: designPlaceholder,

packages/app/src/components/prompt-input.tsx

@@ -1489,7 +1489,7 @@ export const PromptInput: Component<PromptInputProps> = (props) => {
         <PromptImageAttachments
           attachments={imageAttachments()}
           onOpen={(attachment) =>
-            dialog.show(() => <ImagePreview src={attachment.dataUrl} alt={attachment.filename} />)
+            dialog.show(() => <ImagePreview src={attachment.blob.url} alt={attachment.filename} />)
           }
           onRemove={removeAttachment}
           removeLabel={language.t("prompt.attachment.remove")}

packages/app/src/components/prompt-input/attachments.ts

@@ -3,28 +3,13 @@ import { makeEventListener } from "@solid-primitives/event-listener"
 import { showToast } from "@/utils/toast"
 import { type ContentPart, type ImageAttachmentPart, type usePrompt } from "@/context/prompt"
 import { useLanguage } from "@/context/language"
+import { usePlatform } from "@/context/platform"
 import { uuid } from "@/utils/uuid"
 import { getCursorPosition } from "./editor-dom"
+import { createBlobReference, type DraftStore } from "@/utils/draft-store"
 import { attachmentMime } from "./files"
 import { normalizePaste, pasteMode } from "./paste"
 
-function dataUrl(file: File, mime: string) {
-  return new Promise<string>((resolve) => {
-    const reader = new FileReader()
-    reader.addEventListener("error", () => resolve(""))
-    reader.addEventListener("load", () => {
-      const value = typeof reader.result === "string" ? reader.result : ""
-      const idx = value.indexOf(",")
-      if (idx === -1) {
-        resolve(value)
-        return
-      }
-      resolve(`data:${mime};base64,${value.slice(idx + 1)}`)
-    })
-    reader.readAsDataURL(file)
-  })
-}
-
 type PromptTarget = Pick<ReturnType<ReturnType<typeof usePrompt>["capture"]>, "current" | "cursor" | "set">
 type AttachmentTarget = { prompt: PromptTarget; cursor: number | undefined }
 
@@ -36,6 +21,7 @@ type PromptAttachmentsCoreInput = {
   warn?: () => void
   readClipboardImage?: () => Promise<File | null>
   getPathForFile?: (file: File) => string
+  draftStore?: DraftStore
 }
 
 export type PromptAttachmentsInput = {
@@ -65,16 +51,13 @@ export function createPromptAttachmentsCore(input: PromptAttachmentsCoreInput) {
       return false
     }
 
-    const url = await dataUrl(file, mime)
-    if (!url) return false
-
     const attachment: ImageAttachmentPart = {
       type: "image",
       id: uuid(),
       filename: file.name,
       sourcePath: input.getPathForFile?.(file) || undefined,
       mime,
-      dataUrl: url,
+      blob: input.draftStore ? await input.draftStore.putBlob(file) : await createBlobReference(file),
     }
     target.prompt.set([...target.prompt.current(), attachment], target.cursor)
     return true
@@ -166,8 +149,10 @@ export function createPromptAttachmentsCore(input: PromptAttachmentsCoreInput) {
 
 export function createPromptAttachments(input: PromptAttachmentsInput) {
   const language = useLanguage()
+  const platform = usePlatform()
   const attachments = createPromptAttachmentsCore({
     ...input,
+    draftStore: platform.draftStore,
     capture: input.prompt.capture,
     warn: () => {
       showToast({

packages/app/src/components/prompt-input/build-request-parts.ts

@@ -22,7 +22,7 @@ type ContextFile = {
 type BuildRequestPartsInput = {
   prompt: Prompt
   context: ContextFile[]
-  images: ImageAttachmentPart[]
+  images: (Omit<ImageAttachmentPart, "blob"> & { dataUrl: string })[]
   text: string
   messageID: string
   sessionID: string

packages/app/src/components/prompt-input/history-store.ts

@@ -1,7 +1,13 @@
 import { createStore, type SetStoreFunction, type Store } from "solid-js/store"
 import type { Prompt } from "@/context/prompt"
 import { Persist, persisted } from "@/utils/persist"
-import { prependHistoryEntry, type PromptHistoryComment, type PromptHistoryStoredEntry } from "./history"
+import {
+  clonePromptHistoryComments,
+  clonePromptParts,
+  prependHistoryEntry,
+  type PromptHistoryComment,
+  type PromptHistoryStoredEntry,
+} from "./history"
 
 export type PromptInputHistory = {
   entries: (mode: "normal" | "shell") => PromptHistoryStoredEntry[]
@@ -35,13 +41,23 @@ export function createPromptInputHistory(): PromptInputHistory {
 }
 
 export function createPersistedPromptInputHistory() {
-  const [normal, setNormal] = persisted(
-    Persist.global("prompt-history", ["prompt-history.v1"]),
+  const [normal, setNormal, normalInit] = persisted(
+    Persist.prompt(Persist.global("prompt-history", ["prompt-history.v1"])),
     createStore<PromptHistoryState>({ entries: [] }),
   )
-  const [shell, setShell] = persisted(
-    Persist.global("prompt-history-shell", ["prompt-history-shell.v1"]),
+  const [shell, setShell, shellInit] = persisted(
+    Persist.prompt(Persist.global("prompt-history-shell", ["prompt-history-shell.v1"])),
     createStore<PromptHistoryState>({ entries: [] }),
   )
-  return createPromptInputHistoryStore(normal, setNormal, shell, setShell)
+  const history = createPromptInputHistoryStore(normal, setNormal, shell, setShell)
+  return {
+    ...history,
+    add(prompt: Prompt, mode: "normal" | "shell", comments: PromptHistoryComment[]) {
+      const ready = mode === "shell" ? shellInit : normalInit
+      if (!(ready instanceof Promise)) return history.add(prompt, mode, comments)
+      const saved = clonePromptParts(prompt)
+      const metadata = clonePromptHistoryComments(comments)
+      void ready.then(() => history.add(saved, mode, metadata))
+    },
+  }
 }

packages/app/src/components/prompt-input/history.test.ts

@@ -112,7 +112,7 @@ describe("prompt-input history", () => {
         end: 12,
         selection: { startLine: 1, startChar: 1, endLine: 2, endChar: 1 },
       },
-      { type: "image", id: "1", filename: "img.png", mime: "image/png", dataUrl: "data:image/png;base64,abc" },
+      { type: "image", id: "1", filename: "img.png", mime: "image/png", blob: { id: "blob", url: "blob:test" } },
     ]
     const copy = clonePromptParts(original)
     expect(copy).not.toBe(original)

packages/app/src/components/prompt-input/image-attachments.tsx

@@ -100,7 +100,7 @@ export const PromptImageAttachments: Component<PromptImageAttachmentsProps> = (p
                   }
                 >
                   <img
-                    src={attachment.dataUrl}
+                    src={attachment.blob.url}
                     alt={attachment.filename}
                     class={props.newLayoutDesigns ? imageClassV2 : imageClass}
                     onClick={() => props.onOpen(attachment)}

packages/app/src/components/prompt-input/submit.ts

@@ -22,6 +22,7 @@ import { ScopedKey } from "@/utils/server-scope"
 import { createPromptSubmissionState } from "./submission-state"
 import { normalizeSessionInfo } from "@/utils/session"
 import { Event } from "@opencode-ai/schema/event"
+import { blobDataUrl } from "@/utils/draft-store"
 
 type PendingPrompt = {
   abort: AbortController
@@ -95,10 +96,12 @@ export async function sendFollowupDraft(input: FollowupSendInput) {
           providerID: input.draft.model.providerID,
           variant: input.draft.variant,
         },
-        files: images.map((attachment) => ({
-          uri: attachment.dataUrl,
-          name: attachment.filename,
-        })),
+        files: await Promise.all(
+          images.map(async (attachment) => ({
+            uri: await blobDataUrl(attachment.blob, attachment.mime),
+            name: attachment.filename,
+          })),
+        ),
       })
       return true
     } catch (err) {
@@ -108,10 +111,16 @@ export async function sendFollowupDraft(input: FollowupSendInput) {
   }
 
   const messageID = input.messageID ?? Identifier.ascending("message")
+  const encodedImages = await Promise.all(
+    images.map(async (attachment) => ({
+      ...attachment,
+      dataUrl: await blobDataUrl(attachment.blob, attachment.mime),
+    })),
+  )
   const { requestParts, optimisticParts } = buildRequestParts({
     prompt: input.draft.prompt,
     context: input.draft.context,
-    images,
+    images: encodedImages,
     text,
     sessionID: input.draft.sessionID,
     messageID,
@@ -516,10 +525,12 @@ export function createPromptSubmit(input: PromptSubmitInput) {
             arguments: args.join(" "),
             agent,
             model: { id: model.modelID, providerID: model.providerID, variant },
-            files: images.map((attachment) => ({
-              uri: attachment.dataUrl,
-              name: attachment.filename,
-            })),
+            files: await Promise.all(
+              images.map(async (attachment) => ({
+                uri: await blobDataUrl(attachment.blob, attachment.mime),
+                name: attachment.filename,
+              })),
+            ),
           })
           .catch((err) => {
             serverSync().session.set("session_status", session.id, { type: "idle" })

packages/app/src/context/platform.tsx

@@ -5,6 +5,7 @@ import type { DesktopMenuAction } from "../desktop-menu"
 import { ServerConnection } from "./server"
 import type { WslServersPlatform } from "../wsl/types"
 import type { UpdaterPlatform } from "../updater"
+import type { DraftStore } from "@/utils/draft-store"
 
 type PickerPaths = string | string[] | null
 type OpenDirectoryPickerOptions = { title?: string; multiple?: boolean }
@@ -64,6 +65,9 @@ type PlatformBase = {
   /** Storage mechanism, defaults to localStorage */
   storage?: (name?: string) => SyncStorage | AsyncStorage
 
+  /** Prompt drafts, history, and their blobs. */
+  draftStore?: DraftStore
+
   /** Stable platform window identity for window-scoped persistence */
   windowID?: string
 

packages/app/src/context/prompt-state.ts

@@ -5,6 +5,7 @@ import { createStore, type SetStoreFunction } from "solid-js/store"
 import type { FileSelection } from "@/context/file"
 import { Persist, persisted } from "@/utils/persist"
 import type { ServerScope } from "@/utils/server-scope"
+import type { BlobReference } from "@/utils/draft-store"
 
 interface PartBase {
   content: string
@@ -37,7 +38,7 @@ export interface ImageAttachmentPart {
   filename: string
   sourcePath?: string
   mime: string
-  dataUrl: string
+  blob: BlobReference
 }
 
 export type ContentPart = TextPart | FileAttachmentPart | AgentPart | ImageAttachmentPart
@@ -168,9 +169,9 @@ function createPromptActions(setStore: SetStoreFunction<PromptStore>) {
 }
 
 function promptTarget(serverScope: ServerScope, scope: PromptScope) {
-  if ("draftID" in scope) return Persist.draft(scope.draftID, "prompt")
+  if ("draftID" in scope) return Persist.prompt(Persist.draft(scope.draftID, "prompt"))
   const legacy = `${scope.dir}/prompt${scope.id ? "/" + scope.id : ""}.v2`
-  return Persist.serverScoped(serverScope, scope.dir, scope.id, "prompt", [legacy])
+  return Persist.prompt(Persist.serverScoped(serverScope, scope.dir, scope.id, "prompt", [legacy]))
 }
 
 function promptStore(initial?: InitialPrompt): PromptStore {
@@ -245,7 +246,7 @@ export function createPromptSession(serverScope: ServerScope, scope: PromptScope
 }
 
 export function createDraftPromptSession(draftID: string, initial?: InitialPrompt) {
-  return createPersistedPrompt(Persist.draft(draftID, "prompt"), initial)
+  return createPersistedPrompt(Persist.prompt(Persist.draft(draftID, "prompt")), initial)
 }
 
 export type PromptSession = ReturnType<typeof createPromptSession>

packages/app/src/context/tabs.tsx

@@ -101,7 +101,10 @@ export const { use: useTabs, provider: TabsProvider } = createSimpleContext({
     }
 
     const removeDraftPersisted = (draftID: string) => {
-      for (const key of draftPersistedKeys()) removePersisted(Persist.draft(draftID, key), platform)
+      for (const key of draftPersistedKeys()) {
+        const target = Persist.draft(draftID, key)
+        removePersisted(key === "prompt" ? Persist.prompt(target) : target, platform)
+      }
     }
 
     const removeInfo = (key: string) => {

packages/app/src/entry.tsx

@@ -4,6 +4,7 @@ import * as Sentry from "@sentry/solid"
 import { render } from "solid-js/web"
 import { AppBaseProviders, AppInterface } from "@/app"
 import { type Platform, PlatformProvider } from "@/context/platform"
+import { createBrowserDraftStore } from "@/utils/draft-store"
 import { dict as en } from "@/i18n/en"
 import { dict as zh } from "@/i18n/zh"
 import { authFromToken } from "@/utils/server"
@@ -116,6 +117,7 @@ const clearAuthToken = () => {
 
 const platform: Platform = {
   platform: "web",
+  draftStore: createBrowserDraftStore(),
   version: pkg.version,
   openExternal,
   restart,

packages/app/src/index.ts

@@ -27,3 +27,4 @@ export {
   type WslServersState,
 } from "./wsl/types"
 export { ServerConnection } from "./context/server"
+export { createDraftStore, type DraftStore } from "./utils/draft-store"