export type DiffViewLine = {
    kind: 'added';
    newLineNo: number;
    text: string;
} | {
    kind: 'removed';
    oldLineNo: number;
    text: string;
} | {
    kind: 'context';
    oldLineNo: number;
    newLineNo: number;
    text: string;
};
/** Compute a line-level diff view-model. `oldContent === null` ⇒ new file
 *  (every line added). */
export declare function computeDiffLines(oldContent: string | null, newContent: string): DiffViewLine[];