feat: add compat.nanodbc and compat.unixodbc - #210
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nanodbc is a thin C++ wrapper over the platform ODBC driver manager, frozen upstream at v2.14.0 (March 2022). Two fixes make the four-year-old source compile and run under the mcpp toolchain: - a force-included char_traits<unsigned char> shim for libc++ (the standard's own customization point, guarded on _LIBCPP_VERSION; delivered via cxxflags, since cflags never reaches .cpp TUs) - a per-platform answer to the driver manager: windows links the SDK's odbc32, macOS the OS's iODBC, and linux takes the new compat.unixodbc, because mcpp's runtime closure rejects a NEEDED libodbc.so.2 that only the host can provide (its PT_INTERP is a private loader) compat.unixodbc builds the unixODBC 2.3.14 driver manager statically from source (Shape E over A): DM + odbcinst + ini/log/lst + libltdl in one odbc target, exactly upstream's libodbc.a symbol set, so consumers carry no libodbc.so.2 NEEDED at all. The non-obvious pieces, both verified against the libtool build of the same tarball: - libtool-free ltdl wiring: -DLTDLOPEN=libltdlc plus a generated lt_libltdlc_LTX_preloaded_symbols table (reconstructed from the libtool object's relocations) registers the dlopen loader - one merged config.h: ltdl's configure output folded into the top-level one (ltdl sources never read the clashing macros), sidestepping a quoted -DLT_CONFIG_H that does not survive the descriptor -> command-line pipeline The member test is deliberately database-free: connecting to a nonexistent DSN must throw nanodbc::database_error, and the SQL state prefix plus the manager's own message text prove the diagnostics came from the real driver manager. nanodbc 2.14.0's frozen off-by-one (it drops the last SQL-state character) is asserted as a prefix, not equality. Verified: mcpp test -p nanodbc 1/1 cold with no host paths; all lint scripts; mcpp xpkg parse for all 98 descriptors under the pinned 2026.8.10.3; sha256 double-checked for both tarballs. CN mirrors are plain-string GLOBAL for now (no mcpp-res write access), same fallback as compat.libmysqlclient.
Sunrisepeak
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Aug 15, 2026
| -- cxxflags, not cflags -- this package has no C sources. | ||
| cxxflags = { "-include", "mcpp_nanodbc_char_traits.h" }, | ||
| generated_files = { | ||
| ["mcpp_generated/include/mcpp_nanodbc_char_traits.h"] = "// libc++ lacks std::char_traits<unsigned char> (SQLCHAR); nanodbc.cpp uses its ::length().\n// <string> must come FIRST: force-inclusion runs before any libc++ header, so\n// _LIBCPP_VERSION is only defined after <string> has been seen.\n#ifndef MCPP_NANODBC_CHAR_TRAITS_H\n#define MCPP_NANODBC_CHAR_TRAITS_H\n#include <cstdio>\n#include <cstring>\n#include <string>\n#if defined(_LIBCPP_VERSION)\nnamespace std {\ntemplate <>\nstruct char_traits<unsigned char> {\n using char_type = unsigned char;\n using int_type = int;\n using off_type = streamoff;\n using pos_type = fpos<mbstate_t>;\n using state_type = mbstate_t;\n static void assign(char_type& c1, char_type c2) noexcept { c1 = c2; }\n static bool eq(char_type c1, char_type c2) noexcept { return c1 == c2; }\n static bool lt(char_type c1, char_type c2) noexcept { return c1 < c2; }\n static int compare(const char_type* s1, const char_type* s2, size_t n) {\n return n == 0 ? 0 : memcmp(s1, s2, n);\n }\n static size_t length(const char_type* s) {\n return strlen(reinterpret_cast<const char*>(s));\n }\n static const char_type* find(const char_type* s, size_t n, const char_type& a) {\n return static_cast<const char_type*>(memchr(s, a, n));\n }\n static char_type* move(char_type* s1, const char_type* s2, size_t n) {\n return static_cast<char_type*>(memmove(s1, s2, n));\n }\n static char_type* copy(char_type* s1, const char_type* s2, size_t n) {\n return static_cast<char_type*>(memcpy(s1, s2, n));\n }\n static char_type* assign(char_type* s, size_t n, char_type a) {\n return static_cast<char_type*>(memset(s, a, n));\n }\n static int_type not_eof(int_type c) noexcept { return eq_int_type(c, eof()) ? 0 : c; }\n static char_type to_char_type(int_type c) noexcept { return static_cast<char_type>(c); }\n static int_type to_int_type(char_type c) noexcept { return static_cast<int_type>(c); }\n static bool eq_int_type(int_type c1, int_type c2) noexcept { return c1 == c2; }\n static int_type eof() noexcept { return static_cast<int_type>(EOF); }\n};\n} // namespace std\n#endif\n#endif\n", |
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6eef45b提交让ai修改了
… error With string_view support on (C++17+), NANODBC_INSTANTIATE_BIND_STRINGS over std::string and std::string_view emit identical explicit instantiation definitions (both reduce to value_type = char; likewise the u16 pair). Same TU, identical specializations, semantics unaffected -- but GCC (the linux default leg) rejects duplicates where clang accepts silently. CI run 31890353516, workspace (linux default). -fpermissive is GCC's own downgrade for exactly this diagnostic and clang ignores the flag, so the linux leg serves both toolchains.
Review feedback: the single \n-escaped line was unreadable. Lua's .. concatenation is NOT an option here -- the mcpp segment parser rejects it (malformed mcpp segment near key 'string'), so the shim moves to the [==[ ]==] form compat.ffmpeg and compat.sdl2 already use for their generated configs. Content byte-identical to the one-liner.
…syntax boundaries
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跟进两个评审/CI 问题,均已修复且全绿:
第二轮 CI 全部通过(linux default / linux llvm / macos / windows / lint / mirror-cn-reachable)。 |
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Closes #209.
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形态
nanodbc 为 Shape A(
nanodbc.cpp单 TU);unixodbc 为 Shape E 叠 A —— 冻结 configure 快照 + 纯 C 源码直编,消费端零 configure/make,DM + odbcinst + ini/log/lst + libltdl 编入单一odbc目标(即上游libodbc.a的符号集)。三个值得审的判断
-lodbc能编能链,但运行时闭包检查拒绝:mcpp 二进制的 PT_INTERP 是私有 loader,宿主/usr/lib不可达(同 mcpp#352)。静态源码构建让产物不带libodbc.so.2NEEDED,闭包天然通过,亦无宿主 glibc 错配。conan / vcpkg 对 linux ODBC 也是同样结论。dlopen驱动;静态构建下 libtool 的-dlpreopen接线用-DLTDLOPEN=libltdlc+ 一张生成的lt_libltdlc_LTX_preloaded_symbols表(从 libtool 目标文件的重定位还原)复刻。两份 config.h(顶层 / libltdl)合并为一份 —— ltdl 源码不读冲突宏,且带引号的-DLT_CONFIG_H无法穿过描述符 → 命令行管道(实测)。char_traits<unsigned char>:force-include 显式特化(标准定制点,_LIBCPP_VERSION为界,-include走cxxflags,仅作用于本包编译)。nanodbc 截掉 SQL state 末字符的上游 off-by-one 不改源码,测试按真实行为断言前缀。验证
mcpp test -p nanodbc冷构建 1 passed / 0 failed(无任何宿主 include/lib 路径注入,全链路自包含)。lt_dlopen+lt_dlsym行为一致。check_mirror_urls/check_package_name/check_cross_package_refs/check_platform_version_parity全过。mcpp xpkg parse:全部 98 个描述符在钉住的 2026.8.10.3 下通过。测试断言什么
无数据库、无驱动的错误路径:连接不存在的 DSN 必抛
nanodbc::database_error,断言 SQL state 为 "IM002" 的非空前缀(nanodbc 的 off-by-one 会报 "IM00")且what()含管理器原文 "Data source name not found" —— 诊断确实来自真实 driver manager 而非空壳。CN 镜像
无
mcpp-res写权限,暂为纯字符串 GLOBAL url(lint 允许,同compat.libmysqlclient先例),维护者建仓后可补。