| /** | |
| * Request-header reconstruction utilities over full `request/header` session | |
| * events. Anyone holding a session log reconstructs the {@link EpochHeader} | |
| * any request was built under by taking the latest canonical snapshot; the | |
| * loop uses the same equality helper to avoid logging unchanged headers. | |
| * | |
| * @module dsh-session/request-header | |
| */ | |
| import { callConfigEquals } from '@deepseek-ai/dsh-llm' | |
| import type { ToolSchema } from '@deepseek-ai/dsh-llm' | |
| import type { EpochHeader, SessionEvent } from './types.ts' | |
| /** | |
| * Normalize a header to canonical form: an empty tool list becomes an absent | |
| * field, matching how requests are built. Logging, folding, and comparison use | |
| * this one representation. | |
| * @param header - the header to normalize (not mutated). | |
| * @returns the canonical header. | |
| */ | |
| export function canonicalHeader(header: EpochHeader): EpochHeader { | |
| const adapterDefaults = header.adapterDefaults | |
| return { | |
| config: header.config, | |
| ...adapterDefaults?.reasoningEffort === true || adapterDefaults?.maxTokens === true | |
| ? { adapterDefaults } | |
| : {}, | |
| ...header.tools !== undefined && header.tools.length > 0 ? { tools: header.tools } : {}, | |
| } | |
| } | |
| /** Canonical JSON equality for tool schemas assembled through the same path. */ | |
| function sameSchema(a: ToolSchema, b: ToolSchema): boolean { | |
| return JSON.stringify(a) === JSON.stringify(b) | |
| } | |
| /** | |
| * Field-wise equality over canonical headers. Tool schemas compare in order. | |
| * @param a - one canonical header. | |
| * @param b - the other. | |
| * @returns whether config, adapter defaults, and tools all match. | |
| */ | |
| export function headerEquals(a: EpochHeader, b: EpochHeader): boolean { | |
| if ( | |
| !callConfigEquals(a.config, b.config) | |
| || a.adapterDefaults?.reasoningEffort !== b.adapterDefaults?.reasoningEffort | |
| || a.adapterDefaults?.maxTokens !== b.adapterDefaults?.maxTokens | |
| ) return false | |
| const at = a.tools ?? [] | |
| const bt = b.tools ?? [] | |
| return at.length === bt.length && at.every((tool, i) => sameSchema(tool, bt[i] as ToolSchema)) | |
| } | |
| /** | |
| * Fold the header events of a log (or any prefix) into the | |
| * {@link EpochHeader} in force after the last snapshot. Non-header events are | |
| * skipped. This is the pure offline reconstruction path; the live session | |
| * tracks the same fold incrementally. | |
| * @param events - session events in log order. | |
| * @param from - a previously folded state to continue from. | |
| * @returns the latest canonical header, or undefined when none exists yet. | |
| */ | |
| export function foldRequestHeader(events: readonly SessionEvent[], from?: EpochHeader): EpochHeader | undefined { | |
| let state = from | |
| for (const event of events) { | |
| if (event.type === 'request/header') state = canonicalHeader(event.data.header) | |
| } | |
| return state | |
| } | |