libsqlite3-sys 0.28.0

Native bindings to the libsqlite3 library
Documentation
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
use std::env;
use std::path::Path;

/// Tells whether we're building for Windows. This is more suitable than a plain
/// `cfg!(windows)`, since the latter does not properly handle cross-compilation
///
/// Note that there is no way to know at compile-time which system we'll be
/// targetting, and this test must be made at run-time (of the build script) See
/// https://doc.rust-lang.org/cargo/reference/environment-variables.html#environment-variables-cargo-sets-for-build-scripts
fn win_target() -> bool {
    env::var("CARGO_CFG_WINDOWS").is_ok()
}

/// Tells whether we're building for Android.
/// See [`win_target`]
#[cfg(any(feature = "bundled", feature = "bundled-windows"))]
fn android_target() -> bool {
    env::var("CARGO_CFG_TARGET_OS").map_or(false, |v| v == "android")
}

/// Tells whether a given compiler will be used `compiler_name` is compared to
/// the content of `CARGO_CFG_TARGET_ENV` (and is always lowercase)
///
/// See [`win_target`]
fn is_compiler(compiler_name: &str) -> bool {
    env::var("CARGO_CFG_TARGET_ENV").map_or(false, |v| v == compiler_name)
}

/// Copy bindgen file from `dir` to `out_path`.
fn copy_bindings<T: AsRef<Path>>(dir: &str, bindgen_name: &str, out_path: T) {
    let from = if cfg!(feature = "loadable_extension") {
        format!("{dir}/{bindgen_name}_ext.rs")
    } else {
        format!("{dir}/{bindgen_name}.rs")
    };
    std::fs::copy(from, out_path).expect("Could not copy bindings to output directory");
}

fn main() {
    let out_dir = env::var("OUT_DIR").unwrap();
    let out_path = Path::new(&out_dir).join("bindgen.rs");
    if cfg!(feature = "in_gecko") {
        // When inside mozilla-central, we are included into the build with
        // sqlite3.o directly, so we don't want to provide any linker arguments.
        copy_bindings("sqlite3", "bindgen_bundled_version", out_path);
        return;
    }

    println!("cargo:rerun-if-env-changed=LIBSQLITE3_SYS_USE_PKG_CONFIG");
    if env::var_os("LIBSQLITE3_SYS_USE_PKG_CONFIG").map_or(false, |s| s != "0")
        || cfg!(feature = "loadable_extension")
    {
        build_linked::main(&out_dir, &out_path);
    } else if cfg!(all(
        feature = "sqlcipher",
        not(feature = "bundled-sqlcipher")
    )) {
        if cfg!(feature = "bundled") || (win_target() && cfg!(feature = "bundled-windows")) {
            println!(
                "cargo:warning=For backwards compatibility, feature 'sqlcipher' overrides
                features 'bundled' and 'bundled-windows'. If you want a bundled build of
                SQLCipher (available for the moment only on Unix), use feature 'bundled-sqlcipher'
                or 'bundled-sqlcipher-vendored-openssl' to also bundle OpenSSL crypto."
            );
        }
        build_linked::main(&out_dir, &out_path);
    } else if cfg!(feature = "bundled")
        || (win_target() && cfg!(feature = "bundled-windows"))
        || cfg!(feature = "bundled-sqlcipher")
    {
        #[cfg(any(
            feature = "bundled",
            feature = "bundled-windows",
            feature = "bundled-sqlcipher"
        ))]
        build_bundled::main(&out_dir, &out_path);
        #[cfg(not(any(
            feature = "bundled",
            feature = "bundled-windows",
            feature = "bundled-sqlcipher"
        )))]
        panic!("The runtime test should not run this branch, which has not compiled any logic.")
    } else {
        build_linked::main(&out_dir, &out_path);
    }
}

#[cfg(any(
    feature = "bundled",
    feature = "bundled-windows",
    feature = "bundled-sqlcipher"
))]
mod build_bundled {
    use std::env;
    use std::ffi::OsString;
    use std::path::{Path, PathBuf};

    use super::{is_compiler, win_target};

    pub fn main(out_dir: &str, out_path: &Path) {
        let lib_name = super::lib_name();

        // This is just a sanity check, the top level `main` should ensure this.
        assert!(!(cfg!(feature = "bundled-windows") && !cfg!(feature = "bundled") && !win_target()),
            "This module should not be used: we're not on Windows and the bundled feature has not been enabled");

        #[cfg(feature = "buildtime_bindgen")]
        {
            use super::{bindings, HeaderLocation};
            let header = HeaderLocation::FromPath(lib_name.to_owned());
            bindings::write_to_out_dir(header, out_path);
        }
        #[cfg(not(feature = "buildtime_bindgen"))]
        {
            super::copy_bindings(lib_name, "bindgen_bundled_version", out_path);
        }
        println!("cargo:include={}/{lib_name}", env!("CARGO_MANIFEST_DIR"));
        println!("cargo:rerun-if-changed={lib_name}/sqlite3.c");
        println!("cargo:rerun-if-changed=sqlite3/wasm32-wasi-vfs.c");
        let mut cfg = cc::Build::new();
        cfg.file(format!("{lib_name}/sqlite3.c"))
            .flag("-DSQLITE_CORE")
            .flag("-DSQLITE_DEFAULT_FOREIGN_KEYS=1")
            .flag("-DSQLITE_ENABLE_API_ARMOR")
            .flag("-DSQLITE_ENABLE_COLUMN_METADATA")
            .flag("-DSQLITE_ENABLE_DBSTAT_VTAB")
            .flag("-DSQLITE_ENABLE_FTS3")
            .flag("-DSQLITE_ENABLE_FTS3_PARENTHESIS")
            .flag("-DSQLITE_ENABLE_FTS5")
            .flag("-DSQLITE_ENABLE_JSON1")
            .flag("-DSQLITE_ENABLE_LOAD_EXTENSION=1")
            .flag("-DSQLITE_ENABLE_MEMORY_MANAGEMENT")
            .flag("-DSQLITE_ENABLE_RTREE")
            .flag("-DSQLITE_ENABLE_STAT2")
            .flag("-DSQLITE_ENABLE_STAT4")
            .flag("-DSQLITE_SOUNDEX")
            .flag("-DSQLITE_THREADSAFE=1")
            .flag("-DSQLITE_USE_URI")
            .flag("-DHAVE_USLEEP=1")
            .flag("-D_POSIX_THREAD_SAFE_FUNCTIONS") // cross compile with MinGW
            .warnings(false);

        if cfg!(feature = "bundled-sqlcipher") {
            cfg.flag("-DSQLITE_HAS_CODEC").flag("-DSQLITE_TEMP_STORE=2");

            let target = env::var("TARGET").unwrap();
            let host = env::var("HOST").unwrap();

            let is_windows = host.contains("windows") && target.contains("windows");
            let is_apple = host.contains("apple") && target.contains("apple");

            let lib_dir = env("OPENSSL_LIB_DIR").map(PathBuf::from);
            let inc_dir = env("OPENSSL_INCLUDE_DIR").map(PathBuf::from);
            let mut use_openssl = false;

            let (lib_dir, inc_dir) = match (lib_dir, inc_dir) {
                (Some(lib_dir), Some(inc_dir)) => {
                    use_openssl = true;
                    (lib_dir, inc_dir)
                }
                (lib_dir, inc_dir) => match find_openssl_dir(&host, &target) {
                    None => {
                        if is_windows && !cfg!(feature = "bundled-sqlcipher-vendored-openssl") {
                            panic!("Missing environment variable OPENSSL_DIR or OPENSSL_DIR is not set")
                        } else {
                            (PathBuf::new(), PathBuf::new())
                        }
                    }
                    Some(openssl_dir) => {
                        let lib_dir = lib_dir.unwrap_or_else(|| openssl_dir.join("lib"));
                        let inc_dir = inc_dir.unwrap_or_else(|| openssl_dir.join("include"));

                        assert!(
                            Path::new(&lib_dir).exists(),
                            "OpenSSL library directory does not exist: {}",
                            lib_dir.to_string_lossy()
                        );

                        if !Path::new(&inc_dir).exists() {
                            panic!(
                                "OpenSSL include directory does not exist: {}",
                                inc_dir.to_string_lossy()
                            );
                        }

                        use_openssl = true;
                        (lib_dir, inc_dir)
                    }
                },
            };

            if cfg!(feature = "bundled-sqlcipher-vendored-openssl") {
                cfg.include(env::var("DEP_OPENSSL_INCLUDE").unwrap());
                // cargo will resolve downstream to the static lib in
                // openssl-sys
            } else if use_openssl {
                cfg.include(inc_dir.to_string_lossy().as_ref());
                let lib_name = if is_windows { "libcrypto" } else { "crypto" };
                println!("cargo:rustc-link-lib=dylib={}", lib_name);
                println!("cargo:rustc-link-search={}", lib_dir.to_string_lossy());
            } else if is_apple {
                cfg.flag("-DSQLCIPHER_CRYPTO_CC");
                println!("cargo:rustc-link-lib=framework=Security");
                println!("cargo:rustc-link-lib=framework=CoreFoundation");
            } else {
                // branch not taken on Windows, just `crypto` is fine.
                println!("cargo:rustc-link-lib=dylib=crypto");
            }
        }

        // on android sqlite can't figure out where to put the temp files.
        // the bundled sqlite on android also uses `SQLITE_TEMP_STORE=3`.
        // https://android.googlesource.com/platform/external/sqlite/+/2c8c9ae3b7e6f340a19a0001c2a889a211c9d8b2/dist/Android.mk
        if super::android_target() {
            cfg.flag("-DSQLITE_TEMP_STORE=3");
        }

        if cfg!(feature = "with-asan") {
            cfg.flag("-fsanitize=address");
        }

        // If explicitly requested: enable static linking against the Microsoft Visual
        // C++ Runtime to avoid dependencies on vcruntime140.dll and similar libraries.
        if cfg!(target_feature = "crt-static") && is_compiler("msvc") {
            cfg.static_crt(true);
        }

        // Older versions of visual studio don't support c99 (including isnan), which
        // causes a build failure when the linker fails to find the `isnan`
        // function. `sqlite` provides its own implementation, using the fact
        // that x != x when x is NaN.
        //
        // There may be other platforms that don't support `isnan`, they should be
        // tested for here.
        if is_compiler("msvc") {
            use cc::windows_registry::{find_vs_version, VsVers};
            let vs_has_nan = match find_vs_version() {
                Ok(ver) => ver != VsVers::Vs12,
                Err(_msg) => false,
            };
            if vs_has_nan {
                cfg.flag("-DHAVE_ISNAN");
            }
        } else {
            cfg.flag("-DHAVE_ISNAN");
        }
        if !win_target() {
            cfg.flag("-DHAVE_LOCALTIME_R");
        }
        if env::var("TARGET").map_or(false, |v| v == "wasm32-wasi") {
            cfg.flag("-USQLITE_THREADSAFE")
                .flag("-DSQLITE_THREADSAFE=0")
                // https://github.com/rust-lang/rust/issues/74393
                .flag("-DLONGDOUBLE_TYPE=double")
                .flag("-D_WASI_EMULATED_MMAN")
                .flag("-D_WASI_EMULATED_GETPID")
                .flag("-D_WASI_EMULATED_SIGNAL")
                .flag("-D_WASI_EMULATED_PROCESS_CLOCKS");

            if cfg!(feature = "wasm32-wasi-vfs") {
                cfg.file("sqlite3/wasm32-wasi-vfs.c");
            }
        }
        if cfg!(feature = "unlock_notify") {
            cfg.flag("-DSQLITE_ENABLE_UNLOCK_NOTIFY");
        }
        if cfg!(feature = "preupdate_hook") {
            cfg.flag("-DSQLITE_ENABLE_PREUPDATE_HOOK");
        }
        if cfg!(feature = "session") {
            cfg.flag("-DSQLITE_ENABLE_SESSION");
        }

        if let Ok(limit) = env::var("SQLITE_MAX_VARIABLE_NUMBER") {
            cfg.flag(&format!("-DSQLITE_MAX_VARIABLE_NUMBER={limit}"));
        }
        println!("cargo:rerun-if-env-changed=SQLITE_MAX_VARIABLE_NUMBER");

        if let Ok(limit) = env::var("SQLITE_MAX_EXPR_DEPTH") {
            cfg.flag(&format!("-DSQLITE_MAX_EXPR_DEPTH={limit}"));
        }
        println!("cargo:rerun-if-env-changed=SQLITE_MAX_EXPR_DEPTH");

        if let Ok(limit) = env::var("SQLITE_MAX_COLUMN") {
            cfg.flag(&format!("-DSQLITE_MAX_COLUMN={limit}"));
        }
        println!("cargo:rerun-if-env-changed=SQLITE_MAX_COLUMN");

        if let Ok(extras) = env::var("LIBSQLITE3_FLAGS") {
            for extra in extras.split_whitespace() {
                if extra.starts_with("-D") || extra.starts_with("-U") {
                    cfg.flag(extra);
                } else if extra.starts_with("SQLITE_") {
                    cfg.flag(&format!("-D{extra}"));
                } else {
                    panic!("Don't understand {} in LIBSQLITE3_FLAGS", extra);
                }
            }
        }
        println!("cargo:rerun-if-env-changed=LIBSQLITE3_FLAGS");

        cfg.compile(lib_name);

        println!("cargo:lib_dir={out_dir}");
    }

    fn env(name: &str) -> Option<OsString> {
        let prefix = env::var("TARGET").unwrap().to_uppercase().replace('-', "_");
        let prefixed = format!("{prefix}_{name}");
        let var = env::var_os(prefixed);

        match var {
            None => env::var_os(name),
            _ => var,
        }
    }

    fn find_openssl_dir(_host: &str, _target: &str) -> Option<PathBuf> {
        let openssl_dir = env("OPENSSL_DIR");
        openssl_dir.map(PathBuf::from)
    }
}

fn env_prefix() -> &'static str {
    if cfg!(any(feature = "sqlcipher", feature = "bundled-sqlcipher")) {
        "SQLCIPHER"
    } else {
        "SQLITE3"
    }
}

fn lib_name() -> &'static str {
    if cfg!(any(feature = "sqlcipher", feature = "bundled-sqlcipher")) {
        "sqlcipher"
    } else {
        "sqlite3"
    }
}

pub enum HeaderLocation {
    FromEnvironment,
    Wrapper,
    FromPath(String),
}

impl From<HeaderLocation> for String {
    fn from(header: HeaderLocation) -> String {
        match header {
            HeaderLocation::FromEnvironment => {
                let prefix = env_prefix();
                let mut header = env::var(format!("{prefix}_INCLUDE_DIR")).unwrap_or_else(|_| {
                    panic!("{prefix}_INCLUDE_DIR must be set if {prefix}_LIB_DIR is set")
                });
                header.push_str(if cfg!(feature = "loadable_extension") {
                    "/sqlite3ext.h"
                } else {
                    "/sqlite3.h"
                });
                header
            }
            HeaderLocation::Wrapper => if cfg!(feature = "loadable_extension") {
                "wrapper_ext.h"
            } else {
                "wrapper.h"
            }
            .into(),
            HeaderLocation::FromPath(path) => format!(
                "{}/{}",
                path,
                if cfg!(feature = "loadable_extension") {
                    "sqlite3ext.h"
                } else {
                    "sqlite3.h"
                }
            ),
        }
    }
}

mod build_linked {
    #[cfg(feature = "vcpkg")]
    extern crate vcpkg;

    use super::{bindings, env_prefix, is_compiler, lib_name, win_target, HeaderLocation};
    use std::env;
    use std::path::Path;

    pub fn main(_out_dir: &str, out_path: &Path) {
        let header = find_sqlite();
        if (cfg!(any(
            feature = "bundled_bindings",
            feature = "bundled",
            feature = "bundled-sqlcipher"
        )) || (win_target() && cfg!(feature = "bundled-windows")))
            && !cfg!(feature = "buildtime_bindgen")
        {
            // Generally means the `bundled_bindings` feature is enabled.
            // Most users are better off with turning
            // on buildtime_bindgen instead, but this is still supported as we
            // have runtime version checks and there are good reasons to not
            // want to run bindgen.
            super::copy_bindings(lib_name(), "bindgen_bundled_version", out_path);
        } else {
            bindings::write_to_out_dir(header, out_path);
        }
    }

    #[cfg(not(feature = "loadable_extension"))]
    fn find_link_mode() -> &'static str {
        // If the user specifies SQLITE3_STATIC (or SQLCIPHER_STATIC), do static
        // linking, unless it's explicitly set to 0.
        match &env::var(format!("{}_STATIC", env_prefix())) {
            Ok(v) if v != "0" => "static",
            _ => "dylib",
        }
    }
    // Prints the necessary cargo link commands and returns the path to the header.
    fn find_sqlite() -> HeaderLocation {
        let link_lib = lib_name();

        println!("cargo:rerun-if-env-changed={}_INCLUDE_DIR", env_prefix());
        println!("cargo:rerun-if-env-changed={}_LIB_DIR", env_prefix());
        println!("cargo:rerun-if-env-changed={}_STATIC", env_prefix());
        if cfg!(feature = "vcpkg") && is_compiler("msvc") {
            println!("cargo:rerun-if-env-changed=VCPKGRS_DYNAMIC");
        }

        // dependents can access `DEP_SQLITE3_LINK_TARGET` (`sqlite3` being the
        // `links=` value in our Cargo.toml) to get this value. This might be
        // useful if you need to ensure whatever crypto library sqlcipher relies
        // on is available, for example.
        #[cfg(not(feature = "loadable_extension"))]
        println!("cargo:link-target={link_lib}");

        // Allow users to specify where to find SQLite.
        if let Ok(dir) = env::var(format!("{}_LIB_DIR", env_prefix())) {
            // Try to use pkg-config to determine link commands
            let pkgconfig_path = Path::new(&dir).join("pkgconfig");
            env::set_var("PKG_CONFIG_PATH", pkgconfig_path);
            #[cfg(not(feature = "loadable_extension"))]
            if pkg_config::Config::new().probe(link_lib).is_err() {
                // Otherwise just emit the bare minimum link commands.
                println!("cargo:rustc-link-lib={}={link_lib}", find_link_mode());
                println!("cargo:rustc-link-search={dir}");
            }
            return HeaderLocation::FromEnvironment;
        }

        if let Some(header) = try_vcpkg() {
            return header;
        }

        // See if pkg-config can do everything for us.
        if let Ok(mut lib) = pkg_config::Config::new()
            .print_system_libs(false)
            .probe(link_lib)
        {
            if let Some(header) = lib.include_paths.pop() {
                HeaderLocation::FromPath(header.to_string_lossy().into())
            } else {
                HeaderLocation::Wrapper
            }
        } else {
            // No env var set and pkg-config couldn't help; just output the link-lib
            // request and hope that the library exists on the system paths. We used to
            // output /usr/lib explicitly, but that can introduce other linking problems;
            // see https://github.com/rusqlite/rusqlite/issues/207.
            #[cfg(not(feature = "loadable_extension"))]
            println!("cargo:rustc-link-lib={}={link_lib}", find_link_mode());
            HeaderLocation::Wrapper
        }
    }

    fn try_vcpkg() -> Option<HeaderLocation> {
        if cfg!(feature = "vcpkg") && is_compiler("msvc") {
            // See if vcpkg can find it.
            if let Ok(mut lib) = vcpkg::Config::new().probe(lib_name()) {
                if let Some(header) = lib.include_paths.pop() {
                    return Some(HeaderLocation::FromPath(header.to_string_lossy().into()));
                }
            }
            None
        } else {
            None
        }
    }
}

#[cfg(not(feature = "buildtime_bindgen"))]
mod bindings {
    #![allow(dead_code)]
    use super::HeaderLocation;

    use std::path::Path;

    static PREBUILT_BINDGENS: &[&str] = &["bindgen_3.14.0"];

    pub fn write_to_out_dir(_header: HeaderLocation, out_path: &Path) {
        let name = PREBUILT_BINDGENS[PREBUILT_BINDGENS.len() - 1];
        super::copy_bindings("bindgen-bindings", name, out_path);
    }
}

#[cfg(feature = "buildtime_bindgen")]
mod bindings {
    use super::HeaderLocation;
    use bindgen::callbacks::{IntKind, ParseCallbacks};

    use std::path::Path;
    #[derive(Debug)]
    struct SqliteTypeChooser;

    impl ParseCallbacks for SqliteTypeChooser {
        fn int_macro(&self, name: &str, _value: i64) -> Option<IntKind> {
            if name == "SQLITE_SERIALIZE_NOCOPY"
                || name.starts_with("SQLITE_DESERIALIZE_")
                || name.starts_with("SQLITE_PREPARE_")
            {
                Some(IntKind::UInt)
            } else {
                None
            }
        }
    }

    // Are we generating the bundled bindings? Used to avoid emitting things
    // that would be problematic in bundled builds. This env var is set by
    // `upgrade.sh`.
    fn generating_bundled_bindings() -> bool {
        // Hacky way to know if we're generating the bundled bindings
        println!("cargo:rerun-if-env-changed=LIBSQLITE3_SYS_BUNDLING");
        match std::env::var("LIBSQLITE3_SYS_BUNDLING") {
            Ok(v) => v != "0",
            Err(_) => false,
        }
    }

    pub fn write_to_out_dir(header: HeaderLocation, out_path: &Path) {
        let header: String = header.into();
        let mut bindings = bindgen::builder()
            .default_macro_constant_type(bindgen::MacroTypeVariation::Signed)
            .disable_nested_struct_naming()
            .trust_clang_mangling(false)
            .header(header.clone())
            .parse_callbacks(Box::new(SqliteTypeChooser));
        if cfg!(feature = "loadable_extension") {
            bindings = bindings.ignore_functions(); // see generate_functions
        } else {
            bindings = bindings
                .blocklist_function("sqlite3_auto_extension")
                .raw_line(
                    r#"extern "C" {
    pub fn sqlite3_auto_extension(
        xEntryPoint: ::std::option::Option<
            unsafe extern "C" fn(
                db: *mut sqlite3,
                pzErrMsg: *mut *const ::std::os::raw::c_char,
                pThunk: *const sqlite3_api_routines,
            ) -> ::std::os::raw::c_int,
        >,
    ) -> ::std::os::raw::c_int;
}"#,
                )
                .blocklist_function("sqlite3_cancel_auto_extension")
                .raw_line(
                    r#"extern "C" {
    pub fn sqlite3_cancel_auto_extension(
        xEntryPoint: ::std::option::Option<
            unsafe extern "C" fn(
                db: *mut sqlite3,
                pzErrMsg: *mut *const ::std::os::raw::c_char,
                pThunk: *const sqlite3_api_routines,
            ) -> ::std::os::raw::c_int,
        >,
    ) -> ::std::os::raw::c_int;
}"#,
                );
        }

        if cfg!(any(feature = "sqlcipher", feature = "bundled-sqlcipher")) {
            bindings = bindings.clang_arg("-DSQLITE_HAS_CODEC");
        }
        if cfg!(feature = "unlock_notify") {
            bindings = bindings.clang_arg("-DSQLITE_ENABLE_UNLOCK_NOTIFY");
        }
        if cfg!(feature = "preupdate_hook") {
            bindings = bindings.clang_arg("-DSQLITE_ENABLE_PREUPDATE_HOOK");
        }
        if cfg!(feature = "session") {
            bindings = bindings.clang_arg("-DSQLITE_ENABLE_SESSION");
        }

        // When cross compiling unless effort is taken to fix the issue, bindgen
        // will find the wrong headers. There's only one header included by the
        // amalgamated `sqlite.h`: `stdarg.h`.
        //
        // Thankfully, there's almost no case where rust code needs to use
        // functions taking `va_list` (It's nearly impossible to get a `va_list`
        // in Rust unless you get passed it by C code for some reason).
        //
        // Arguably, we should never be including these, but we include them for
        // the cases where they aren't totally broken...
        let target_arch = std::env::var("TARGET").unwrap();
        let host_arch = std::env::var("HOST").unwrap();
        let is_cross_compiling = target_arch != host_arch;

        // Note that when generating the bundled file, we're essentially always
        // cross compiling.
        if generating_bundled_bindings() || is_cross_compiling {
            // Get rid of va_list, as it's not
            bindings = bindings
                .blocklist_function("sqlite3_vmprintf")
                .blocklist_function("sqlite3_vsnprintf")
                .blocklist_function("sqlite3_str_vappendf")
                .blocklist_type("va_list")
                .blocklist_item("__.*");
        }

        let bindings = bindings
            .layout_tests(false)
            .generate()
            .unwrap_or_else(|_| panic!("could not run bindgen on header {}", header));

        #[cfg(feature = "loadable_extension")]
        {
            let mut output = Vec::new();
            bindings
                .write(Box::new(&mut output))
                .expect("could not write output of bindgen");
            let mut output = String::from_utf8(output).expect("bindgen output was not UTF-8?!");
            super::loadable_extension::generate_functions(&mut output);
            std::fs::write(out_path, output.as_bytes())
                .unwrap_or_else(|_| panic!("Could not write to {:?}", out_path));
        }
        #[cfg(not(feature = "loadable_extension"))]
        bindings
            .write_to_file(out_path)
            .unwrap_or_else(|_| panic!("Could not write to {:?}", out_path));
    }
}

#[cfg(all(feature = "buildtime_bindgen", feature = "loadable_extension"))]
mod loadable_extension {
    /// try to generate similar rust code for all `#define sqlite3_xyz
    /// sqlite3_api->abc` macros` in sqlite3ext.h
    pub fn generate_functions(output: &mut String) {
        // (1) parse sqlite3_api_routines fields from bindgen output
        let ast: syn::File = syn::parse_str(output).expect("could not parse bindgen output");
        let sqlite3_api_routines: syn::ItemStruct = ast
            .items
            .into_iter()
            .find_map(|i| {
                if let syn::Item::Struct(s) = i {
                    if s.ident == "sqlite3_api_routines" {
                        Some(s)
                    } else {
                        None
                    }
                } else {
                    None
                }
            })
            .expect("could not find sqlite3_api_routines");
        let sqlite3_api_routines_ident = sqlite3_api_routines.ident;
        let p_api = quote::format_ident!("p_api");
        let mut stores = Vec::new();
        let mut malloc = Vec::new();
        // (2) `#define sqlite3_xyz sqlite3_api->abc` => `pub unsafe fn
        // sqlite3_xyz(args) -> ty {...}` for each `abc` field:
        for field in sqlite3_api_routines.fields {
            let ident = field.ident.expect("unamed field");
            let span = ident.span();
            let name = ident.to_string();
            if name == "vmprintf" || name == "xvsnprintf" || name == "str_vappendf" {
                continue; // skip va_list
            } else if name == "aggregate_count"
                || name == "expired"
                || name == "global_recover"
                || name == "thread_cleanup"
                || name == "transfer_bindings"
            {
                continue; // omit deprecated
            }
            let sqlite3_name = match name.as_ref() {
                "xthreadsafe" => "sqlite3_threadsafe".to_owned(),
                "interruptx" => "sqlite3_interrupt".to_owned(),
                _ => {
                    format!("sqlite3_{name}")
                }
            };
            let ptr_name =
                syn::Ident::new(format!("__{}", sqlite3_name.to_uppercase()).as_ref(), span);
            let sqlite3_fn_name = syn::Ident::new(&sqlite3_name, span);
            let method =
                extract_method(&field.ty).unwrap_or_else(|| panic!("unexpected type for {name}"));
            let arg_names: syn::punctuated::Punctuated<&syn::Ident, syn::token::Comma> = method
                .inputs
                .iter()
                .map(|i| &i.name.as_ref().unwrap().0)
                .collect();
            let args = &method.inputs;
            // vtab_config/sqlite3_vtab_config: ok
            let varargs = &method.variadic;
            if varargs.is_some() && "db_config" != name && "log" != name && "vtab_config" != name {
                continue; // skip ...
            }
            let ty = &method.output;
            let tokens = if "db_config" == name {
                quote::quote! {
                    static #ptr_name: ::std::sync::atomic::AtomicPtr<()> = ::std::sync::atomic::AtomicPtr::new(::std::ptr::null_mut());
                    pub unsafe fn #sqlite3_fn_name(#args arg3: ::std::os::raw::c_int, arg4: *mut ::std::os::raw::c_int) #ty {
                        let ptr = #ptr_name.load(::std::sync::atomic::Ordering::Acquire);
                        assert!(!ptr.is_null(), "SQLite API not initialized");
                        let fun: unsafe extern "C" fn(#args #varargs) #ty = ::std::mem::transmute(ptr);
                        (fun)(#arg_names, arg3, arg4)
                    }
                }
            } else if "log" == name {
                quote::quote! {
                    static #ptr_name: ::std::sync::atomic::AtomicPtr<()> = ::std::sync::atomic::AtomicPtr::new(::std::ptr::null_mut());
                    pub unsafe fn #sqlite3_fn_name(#args arg3: *const ::std::os::raw::c_char) #ty {
                        let ptr = #ptr_name.load(::std::sync::atomic::Ordering::Acquire);
                        assert!(!ptr.is_null(), "SQLite API not initialized");
                        let fun: unsafe extern "C" fn(#args #varargs) #ty = ::std::mem::transmute(ptr);
                        (fun)(#arg_names, arg3)
                    }
                }
            } else {
                quote::quote! {
                    static #ptr_name: ::std::sync::atomic::AtomicPtr<()> = ::std::sync::atomic::AtomicPtr::new(::std::ptr::null_mut());
                    pub unsafe fn #sqlite3_fn_name(#args) #ty {
                        let ptr = #ptr_name.load(::std::sync::atomic::Ordering::Acquire);
                        assert!(!ptr.is_null(), "SQLite API not initialized or SQLite feature omitted");
                        let fun: unsafe extern "C" fn(#args #varargs) #ty = ::std::mem::transmute(ptr);
                        (fun)(#arg_names)
                    }
                }
            };
            output.push_str(&prettyplease::unparse(
                &syn::parse2(tokens).expect("could not parse quote output"),
            ));
            output.push('\n');
            if name == "malloc" {
                &mut malloc
            } else {
                &mut stores
            }
            .push(quote::quote! {
                if let Some(fun) = (*#p_api).#ident {
                    #ptr_name.store(
                        fun as usize as *mut (),
                        ::std::sync::atomic::Ordering::Release,
                    );
                }
            });
        }
        // (3) generate rust code similar to SQLITE_EXTENSION_INIT2 macro
        let tokens = quote::quote! {
            /// Like SQLITE_EXTENSION_INIT2 macro
            pub unsafe fn rusqlite_extension_init2(#p_api: *mut #sqlite3_api_routines_ident) -> ::std::result::Result<(),crate::InitError> {
                #(#malloc)* // sqlite3_malloc needed by to_sqlite_error
                if let Some(fun) = (*#p_api).libversion_number {
                    let version = fun();
                    if SQLITE_VERSION_NUMBER > version {
                        return Err(crate::InitError::VersionMismatch{compile_time: SQLITE_VERSION_NUMBER, runtime: version});
                    }
                } else {
                    return Err(crate::InitError::NullFunctionPointer);
                }
                #(#stores)*
                Ok(())
            }
        };
        output.push_str(&prettyplease::unparse(
            &syn::parse2(tokens).expect("could not parse quote output"),
        ));
        output.push('\n');
    }

    fn extract_method(ty: &syn::Type) -> Option<&syn::TypeBareFn> {
        match ty {
            syn::Type::Path(tp) => tp.path.segments.last(),
            _ => None,
        }
        .map(|seg| match &seg.arguments {
            syn::PathArguments::AngleBracketed(args) => args.args.first(),
            _ => None,
        })?
        .map(|arg| match arg {
            syn::GenericArgument::Type(t) => Some(t),
            _ => None,
        })?
        .map(|ty| match ty {
            syn::Type::BareFn(r) => Some(r),
            _ => None,
        })?
    }
}