# name: test/sql/functions/duck_vfs.test
# description: duckfn::duck_vfs 便捷读写在真实（本地）文件系统上的行为：存在性、覆盖、追加、FailIfExists、字节数、缺失文件报错
# group: [functions]
require duckfn
# ============================================================================
# 这些是「原生」用例：duck_vfs 走 DuckDB 的 VFS，在真实磁盘（__TEST_DIR__）上语义
# 与 POSIX 一致 —— 缺失文件 open 失败，故 dfn_file_exists 为 false；覆盖会把更长的
# 旧文件截短；追加接到末尾。
#
# 浏览器 / DuckDB-Wasm 上这一层**不可靠**：那套裸文件系统对不存在的文件 open 也「成功」
# 并返回零填充的垃圾，且写 / 追加的字节序不按 POSIX 走，而 DuckDB 的 C API 没有真正的
# 存在性接口可供扩展侧纠正。所以文件系统相关的示例在文档站保持普通代码块，wasm 端不
# 纳入本用例（sqllogictest 只在原生 DuckDB 上跑）。
#
# These are the *native* cases. On a real (local) file system duck_vfs behaves
# like POSIX. On the browser / DuckDB-Wasm build the raw file system is not
# faithful (a missing file opens "successfully" and reads back zero-filled
# bytes; write/append order is wrong) and DuckDB's C API exposes no real
# existence primitive to correct it — hence file-system examples stay plain
# code blocks on the docs site, and this suite only runs on native DuckDB.
# ============================================================================
# ---------------------------------------------------------------------------
# 存在性：从未写过的文件不存在
# ---------------------------------------------------------------------------
query T
SELECT dfn_file_exists('__TEST_DIR__/dfn_vfs_missing.txt');
----
false
# ---------------------------------------------------------------------------
# 写文本 → 字节数、存在、大小、内容
# ---------------------------------------------------------------------------
query I
SELECT dfn_file_write_text('__TEST_DIR__/dfn_vfs_a.txt', 'hello');
----
5
query T
SELECT dfn_file_exists('__TEST_DIR__/dfn_vfs_a.txt');
----
true
query T
SELECT dfn_file_exists('__TEST_DIR__/dfn_vfs_missing.txt');
----
false
query I
SELECT dfn_file_size('__TEST_DIR__/dfn_vfs_a.txt');
----
5
query T
SELECT dfn_file_read_text('__TEST_DIR__/dfn_vfs_a.txt');
----
hello
# ---------------------------------------------------------------------------
# 追加：接到末尾，长度随之增长
# ---------------------------------------------------------------------------
query I
SELECT dfn_file_append_text('__TEST_DIR__/dfn_vfs_a.txt', '!!');
----
2
query I
SELECT dfn_file_size('__TEST_DIR__/dfn_vfs_a.txt');
----
7
query T
SELECT dfn_file_read_text('__TEST_DIR__/dfn_vfs_a.txt');
----
hello!!
# ---------------------------------------------------------------------------
# 覆盖（Replace）：把更长的旧文件写成更短的新内容，不留残渣
# ---------------------------------------------------------------------------
query I
SELECT dfn_file_write_text('__TEST_DIR__/dfn_vfs_a.txt', 'hi');
----
2
query T
SELECT dfn_file_read_text('__TEST_DIR__/dfn_vfs_a.txt');
----
hi
query I
SELECT dfn_file_size('__TEST_DIR__/dfn_vfs_a.txt');
----
2
# ---------------------------------------------------------------------------
# FailIfExists：文件已存在则报错，且不改动原内容
# ---------------------------------------------------------------------------
statement error
SELECT dfn_file_write_text_new('__TEST_DIR__/dfn_vfs_a.txt', 'nope');
----
already exists
query T
SELECT dfn_file_read_text('__TEST_DIR__/dfn_vfs_a.txt');
----
hi
# FailIfExists：文件不存在则正常写入
query I
SELECT dfn_file_write_text_new('__TEST_DIR__/dfn_vfs_new.txt', 'first');
----
5
# ---------------------------------------------------------------------------
# 错误路径：缺失文件读 / 取字节数都报错（带 duckfn 前缀，不依赖各平台系统措辞）
# ---------------------------------------------------------------------------
statement error
SELECT dfn_file_read_text('__TEST_DIR__/dfn_vfs_missing.txt');
----
duckfn::duck_vfs::read
statement error
SELECT dfn_file_size('__TEST_DIR__/dfn_vfs_missing.txt');
----
duckfn::duck_vfs::size