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
use crate::cmd::{cfg_spinner, fail_spinner, run_stage, succeed_spinner};
use crate::errors::*;
use crate::parse::Opts;
use cargo_lock::Lockfile;
use cargo_metadata::MetadataCommand;
use console::Emoji;
use directories::ProjectDirs;
use flate2::read::GzDecoder;
use futures::future::try_join;
use indicatif::ProgressBar;
use reqwest::Client;
use std::borrow::BorrowMut;
use std::fs;
use std::fs::File;
use std::{
    path::{Path, PathBuf},
    process::Command,
};
use tar::Archive;
use tokio::io::AsyncWriteExt;

static INSTALLING: Emoji<'_, '_> = Emoji("📥", "");
static GENERATING_LOCKFILE: Emoji<'_, '_> = Emoji("🔏", "");

// For each of the tools installed in this file, we preferentially
// manually download it. If that can't be achieved due to a platform
// mismatch, then we'll see if the user already has a version installed.
//
// Importantly, if the user has specified an environment variable specifying
// where a tool can be found, we'll use that no matter what.

/// Gets the directory to store tools in. This will preferentially use the
/// system-wide cache, falling back to a local version.
///
/// If the user specifies that we're running on CI, we'll use the local version
/// regardless.
pub fn get_tools_dir(project: &Path, no_system_cache: bool) -> Result<PathBuf, InstallError> {
    match ProjectDirs::from("", "perseus", "perseus_cli") {
        Some(dirs) if !no_system_cache => {
            let target = dirs.cache_dir().join("tools");
            if target.exists() {
                Ok(target)
            } else {
                // Try to create the system-wide cache
                if fs::create_dir_all(&target).is_ok() {
                    Ok(target)
                } else {
                    // Failed, so we'll resort to the local cache
                    let target = project.join("dist/tools");
                    if !target.exists() {
                        // If this fails, we have no recourse, so we'll have to fail
                        fs::create_dir_all(&target)
                            .map_err(|err| InstallError::CreateToolsDirFailed { source: err })?;
                    }
                    // It either already existed or we've just created it
                    Ok(target)
                }
            }
        }
        _ => {
            let target = project.join("dist/tools");
            if !target.exists() {
                // If this fails, we have no recourse, so we'll have to fail
                fs::create_dir_all(&target)
                    .map_err(|err| InstallError::CreateToolsDirFailed { source: err })?;
            }
            // It either already existed or we've just created it
            Ok(target)
        }
    }
}

/// A representation of the paths to all the external tools we need.
/// This includes `cargo`, simply for convenience, even though it's not
/// actually independently installed.
///
/// This does not contain metadata for the installation process, but is rather
/// intended to be passed around through the rest of the CLI.
#[derive(Clone)]
pub struct Tools {
    /// The path to `cargo` on the engine-side.
    pub cargo_engine: String,
    /// The path to `cargo` on the browser-side.
    pub cargo_browser: String,
    /// The path to `wasm-bindgen`.
    pub wasm_bindgen: String,
    /// The path to `wasm-opt`.
    pub wasm_opt: String,
}
impl Tools {
    /// Gets a new instance of `Tools` by installing the tools if necessary.
    ///
    /// If tools are installed, this will create a CLI spinner automatically.
    pub async fn new(dir: &Path, global_opts: &Opts) -> Result<Self, InstallError> {
        // First, make sure `Cargo.lock` exists, since we'll need it for determining the
        // right version of `wasm-bindgen`
        let metadata = MetadataCommand::new()
            .no_deps()
            .cargo_path(&global_opts.cargo_engine_path)
            .exec()
            .map_err(|err| InstallError::MetadataFailed { source: err })?;
        let workspace_root = metadata.workspace_root.into_std_path_buf();
        let lockfile_path = workspace_root.join("Cargo.lock");
        if !lockfile_path.exists() {
            let lf_msg = format!("{} Generating Cargo lockfile", GENERATING_LOCKFILE);
            let lf_spinner = cfg_spinner(ProgressBar::new_spinner(), &lf_msg);
            let (_stdout, _stderr, exit_code) = run_stage(
                vec![&format!(
                    "{} generate-lockfile",
                    global_opts.cargo_engine_path
                )],
                &workspace_root,
                &lf_spinner,
                &lf_msg,
                vec![
                    ("RUSTFLAGS", "--cfg=engine"),
                    ("CARGO_TERM_COLOR", "always"),
                ],
                // Sure, the user *might* want logs on this process (but this will only be run the
                // first time)
                global_opts.verbose,
            )
            .map_err(|err| InstallError::LockfileGenerationFailed { source: err })?;
            if exit_code != 0 {
                // The output has already been handled, just terminate
                return Err(InstallError::LockfileGenerationNonZero { code: exit_code });
            }
        }
        let lockfile = Lockfile::load(lockfile_path)
            .map_err(|err| InstallError::LockfileLoadFailed { source: err })?;

        let target = get_tools_dir(dir, global_opts.no_system_tools_cache)?;

        // Instantiate the tools
        let wasm_bindgen = Tool::new(
            ToolType::WasmBindgen,
            &global_opts.wasm_bindgen_path,
            &global_opts.wasm_bindgen_version,
        );
        let wasm_opt = Tool::new(
            ToolType::WasmOpt,
            &global_opts.wasm_opt_path,
            &global_opts.wasm_opt_version,
        );

        // Get the statuses of all the tools
        let wb_status = wasm_bindgen.get_status(&target, &lockfile)?;
        let wo_status = wasm_opt.get_status(&target, &lockfile)?;
        // Figure out if everything is present
        // This is the only case in which we don't have to start the spinner
        if let (ToolStatus::Available(wb_path), ToolStatus::Available(wo_path)) =
            (&wb_status, &wo_status)
        {
            #[cfg(unix)]
            let (wb_path, wo_path) = (wb_path.to_string(), wo_path.to_string());
            #[cfg(windows)]
            let (wb_path, wo_path) = (format!("& \'{}\'", wb_path), format!("& \'{}\'", wo_path));
            Ok(Tools {
                cargo_engine: global_opts.cargo_engine_path.clone(),
                cargo_browser: global_opts.cargo_browser_path.clone(),
                wasm_bindgen: wb_path,
                wasm_opt: wo_path,
            })
        } else {
            // We need to install some things, which may take some time
            let spinner_msg = format!("{} Installing external tools", INSTALLING);
            let spinner = cfg_spinner(ProgressBar::new_spinner(), &spinner_msg);

            // Install all the tools in parallel
            // These functions sanity-check their statuses, so we don't need to worry about
            // installing unnecessarily
            let res = try_join(
                wasm_bindgen.install(wb_status, &target),
                wasm_opt.install(wo_status, &target),
            )
            .await;
            if let Err(err) = res {
                fail_spinner(&spinner, &spinner_msg);
                return Err(err);
            }
            // If we're here, we have the paths
            succeed_spinner(&spinner, &spinner_msg);
            let paths = res.unwrap();
            #[cfg(unix)]
            let (wb_path, wo_path) = paths;
            #[cfg(windows)]
            let (wb_path, wo_path) = (format!("& \'{}\'", paths.0), format!("& \'{}\'", paths.1));

            Ok(Tools {
                cargo_engine: global_opts.cargo_engine_path.clone(),
                cargo_browser: global_opts.cargo_browser_path.clone(),
                wasm_bindgen: wb_path,
                wasm_opt: wo_path,
            })
        }
    }
}

/// The data we need about an external tool to be able to install it.
///
/// This does not contain data about arguments to these tools, that's passed
/// through the global options to the CLI directly (with defaults hardcoded).
pub struct Tool {
    /// The name of the tool. This will also be used for the name of the
    /// directory in `dist/tools/` in which the tool is stored (with the
    /// version number added on).
    pub name: String,
    /// A path provided by the user to the tool. If this is present, then the
    /// tool won't be installed, we'll use what the user has given us
    /// instead.
    pub user_given_path: Option<String>,
    /// A specific version number provided by the user. By default, the latest
    /// version is used.
    pub user_given_version: Option<String>,
    /// The path to the binary within the directory that is extracted from the
    /// downloaded archive.
    pub final_path: String,
    /// The name of the GitHub repo from which the tool can be downloaded.
    pub gh_repo: String,
    /// The name of the directory that will be extracted. This should contain
    /// `%version` to be replaced with the actual version and/or
    /// `%artifact_name` to be replaced with that.
    pub extracted_dir_name: String,
    /// The actual type of the tool. (All tools have the same data.)
    pub tool_type: ToolType,
}
impl Tool {
    /// Creates a new instance of this `struct`.
    pub fn new(
        tool_type: ToolType,
        user_given_path: &Option<String>,
        user_given_version: &Option<String>,
    ) -> Self {
        // Correct the final path for Windows (on which it'll have a `.exe` extension)
        #[cfg(unix)]
        let final_path = tool_type.final_path();
        #[cfg(windows)]
        let final_path = tool_type.final_path() + ".exe";

        Self {
            name: tool_type.name(),
            user_given_path: user_given_path.to_owned(),
            user_given_version: user_given_version.to_owned(),
            final_path,
            gh_repo: tool_type.gh_repo(),
            extracted_dir_name: tool_type.extracted_dir_name(),
            tool_type,
        }
    }
    /// Gets the name of the artifact to download based on the tool data and the
    /// version to download. Note that the version provided here entirely
    /// overrides anything the user might have provided.
    ///
    /// If no precompiled binary is expected to be available for the current
    /// platform, this will return `None`.
    fn get_artifact_name(&self, version: &str) -> Option<String> {
        match &self.tool_type {
            // --- `wasm-bindgen` ---
            // Linux
            ToolType::WasmBindgen if cfg!(target_os = "linux") && cfg!(target_arch = "x86_64") => {
                Some("wasm-bindgen-%version-x86_64-unknown-linux-musl")
            }
            // MacOS (Intel)
            ToolType::WasmBindgen if cfg!(target_os = "macos") && cfg!(target_arch = "x86_64") => {
                Some("wasm-bindgen-%version-x86_64-apple-darwin")
            }
            // MacOS (Apple Silicon)
            ToolType::WasmBindgen if cfg!(target_os = "macos") && cfg!(target_arch = "aarch64") => {
                Some("wasm-bindgen-%version-a   arch64-apple-darwin")
            }
            // Windows
            ToolType::WasmBindgen
                if cfg!(target_os = "windows") && cfg!(target_arch = "x86_64") =>
            {
                Some("wasm-bindgen-%version-x86_64-pc-windows-msvc")
            }
            ToolType::WasmBindgen => None,
            // --- `wasm-opt` ---
            // Linux
            ToolType::WasmOpt if cfg!(target_os = "linux") && cfg!(target_arch = "x86_64") => {
                Some("binaryen-%version-x86_64-linux")
            }
            // MacOS (Intel)
            ToolType::WasmOpt if cfg!(target_os = "macos") && cfg!(target_arch = "x86_64") => {
                Some("binaryen-%version-x86_64-macos")
            }
            // MacOS (Apple Silicon)
            ToolType::WasmOpt if cfg!(target_os = "macos") && cfg!(target_arch = "aarch64") => {
                Some("binaryen-%version-arm64-macos")
            }
            // Windows
            ToolType::WasmOpt if cfg!(target_os = "windows") && cfg!(target_arch = "x86_64") => {
                Some("binaryen-%version-x86_64-windows")
            }
            ToolType::WasmOpt => None,
        }
        .map(|s| s.replace("%version", version))
    }
    /// Gets the path to the already-installed version of the tool to use. This
    /// should take the full path to `dist/tools/`. This will automatically
    /// handle whether or not to install a new version, use a version already
    /// installed globally on the user's system, etc. If this returns
    /// `ToolStatus::NeedsInstall`, we can be sure that there are binaries
    /// available, and the same if it returns `ToolStatus::NeedsLatestInstall`.
    pub fn get_status(
        &self,
        target: &Path,
        lockfile: &Lockfile,
    ) -> Result<ToolStatus, InstallError> {
        // The status information will be incomplete from this first pass
        let initial_status = {
            // If there's a directory that matches with a given user version, we'll use it.
            // If not, we'll use the latest version. Only if there are no
            // installed versions available will this return `None`, or if the user wants a
            // specific one that doesn't exist.

            // If the user has given us a path, that overrides everything
            if let Some(path) = &self.user_given_path {
                Ok(ToolStatus::Available(path.to_string()))
            } else {
                // If they've given us a version, we'll check if that directory exists (we don't
                // care about any others)
                if let Some(version) = &self.user_given_version {
                    // If the user wants the latest version, just force an update
                    if version == "latest" {
                        Ok(ToolStatus::NeedsLatestInstall)
                    } else {
                        let expected_path = target.join(format!("{}-{}", self.name, version));
                        Ok(if fs::metadata(&expected_path).is_ok() {
                            ToolStatus::Available(
                                expected_path
                                    .join(&self.final_path)
                                    .to_string_lossy()
                                    .to_string(),
                            )
                        } else {
                            ToolStatus::NeedsInstall {
                                version: version.to_string(),
                                // This will be filled in on the second pass-through
                                artifact_name: String::new(),
                            }
                        })
                    }
                } else {
                    // We have no further information from the user, so we'll use whatever matches
                    // the user's `Cargo.lock`, or, if they haven't specified anything, we'll try
                    // the latest version.
                    // Either way, we need to know what we've got installed already by walking the
                    // directory.
                    let mut versions: Vec<String> = Vec::new();
                    for entry in fs::read_dir(target)
                        .map_err(|err| InstallError::ReadToolsDirFailed { source: err })?
                    {
                        let entry = entry
                            .map_err(|err| InstallError::ReadToolsDirFailed { source: err })?;
                        let dir_name = entry.file_name().to_string_lossy().to_string();
                        if dir_name.starts_with(&self.name) {
                            let dir_name_ref = dir_name.to_string();
                            // Valid directory names are of the form `<tool-name>-<tool-version>`
                            let version = dir_name
                                .strip_prefix(&format!("{}-", self.name))
                                .ok_or(InstallError::InvalidToolsDirName { name: dir_name_ref })?;
                            versions.push(version.to_string());
                        }
                    }
                    // Now order those from most recent to least recent
                    versions.sort();
                    let versions = versions.into_iter().rev().collect::<Vec<String>>();

                    // Now figure out what would match the current setup by checking `Cargo.lock`
                    // (it's entirely possible that there are multiple versions
                    // of `wasm-bindgen` in here, but that would be the user's problem).
                    // It doesn't matter that we do this erroneously for other tools, since they'll
                    // just return `None`.
                    match self.get_pkg_version_from_lockfile(lockfile)? {
                        Some(version) => {
                            if versions.contains(&version) {
                                let path_to_version = target
                                    .join(format!("{}-{}/{}", self.name, version, self.final_path));
                                Ok(ToolStatus::Available(
                                    path_to_version.to_string_lossy().to_string(),
                                ))
                            } else {
                                Ok(ToolStatus::NeedsInstall {
                                    version,
                                    // This will be filled in on the second pass-through
                                    artifact_name: String::new(),
                                })
                            }
                        }
                        // There's nothing in the lockfile, so we'll go with the latest we have
                        // installed
                        None => {
                            // If there are any at all, pick the first one
                            if !versions.is_empty() {
                                let latest_available_version = &versions[0];
                                // We know the directory for this version had a valid name, so we
                                // can determine exactly where it
                                // was
                                let path_to_latest_version = target.join(format!(
                                    "{}-{}/{}",
                                    self.name, latest_available_version, self.final_path
                                ));
                                Ok(ToolStatus::Available(
                                    path_to_latest_version.to_string_lossy().to_string(),
                                ))
                            } else {
                                // We don't check the latest version here because we haven't started
                                // the spinner yet
                                Ok(ToolStatus::NeedsLatestInstall)
                            }
                        }
                    }
                }
            }
        }?;
        // If we're considering installing something, we should make sure that there are
        // actually precompiled binaries available for this platform (if there
        // aren't, then we'll try to fall back on anything the user has installed
        // locally, and if they have nothing, an error will be returned)
        match initial_status {
            ToolStatus::Available(path) => Ok(ToolStatus::Available(path)),
            ToolStatus::NeedsInstall { version, .. } => {
                // This will be `None` if there are no precompiled binaries available
                let artifact_name = self.get_artifact_name(&version);
                if let Some(artifact_name) = artifact_name {
                    // There are precompiled binaries available, which we prefer to preinstalled
                    // global ones
                    Ok(ToolStatus::NeedsInstall {
                        version,
                        artifact_name,
                    })
                } else {
                    // If the user has something, we're good, but, if not, we have to fail
                    let preinstalled_path = self.get_path_to_preinstalled()?;
                    // We've got something, but it might not be the right version, so if the user
                    // told us to use a specific version, we should warn them
                    if self.user_given_version.is_some() {
                        eprintln!("[WARNING]: You requested a specific version, but no precompiled binaries of '{}' are available for your platform, so the version already installed on your system is being used. This may not correspond to the requested version!", self.name);
                    }
                    Ok(ToolStatus::Available(preinstalled_path))
                }
            }
            ToolStatus::NeedsLatestInstall => {
                // To get the proper artifact name for this, we would have to request the latest
                // version, but we don't want to do that until a CLI spinner has
                // been started, which is after the execution of this function (so we just use a
                // dummy version to check if there would be binaries)
                // This will be `None` if there are no precompiled binaries available
                let artifact_name = self.get_artifact_name("dummy");
                if artifact_name.is_some() {
                    // There are precompiled binaries available, which we prefer to preinstalled
                    // global ones
                    Ok(ToolStatus::NeedsLatestInstall)
                } else {
                    // If the user has something, we're good, but, if not, we have to fail
                    let preinstalled_path = self.get_path_to_preinstalled()?;
                    // The user can't have requested a specific version if we're in the market for
                    // the latest one, so we can wrap up here
                    Ok(ToolStatus::Available(preinstalled_path))
                }
            }
        }
    }
    /// Gets the latest version for this tool from its GitHub repository. One
    /// should only bother executing this if we know there are precompiled
    /// binaries for this platform.
    pub async fn get_latest_version(&self) -> Result<String, InstallError> {
        let json = Client::new()
            .get(&format!(
                "https://api.github.com/repos/{}/releases/latest",
                self.gh_repo
            ))
            // This needs to display the name of the app for GH
            .header("User-Agent", "perseus-cli")
            .send()
            .await
            .map_err(|err| InstallError::GetLatestToolVersionFailed {
                source: err,
                tool: self.name.to_string(),
            })?
            .json::<serde_json::Value>()
            .await
            .map_err(|err| InstallError::GetLatestToolVersionFailed {
                source: err,
                tool: self.name.to_string(),
            })?;
        let latest_version =
            json.get("name")
                .ok_or_else(|| InstallError::ParseToolVersionFailed {
                    tool: self.name.to_string(),
                })?;

        Ok(latest_version
            .as_str()
            .ok_or_else(|| InstallError::ParseToolVersionFailed {
                tool: self.name.to_string(),
            })?
            .to_string())
    }
    /// Installs the tool, taking the predetermined status as an argument to
    /// avoid installing if the tool is actually already available, since
    /// this method will be called on all tools if even one
    /// is not available.
    pub async fn install(&self, status: ToolStatus, target: &Path) -> Result<String, InstallError> {
        // Do a sanity check to prevent installing something that already exists
        match status {
            ToolStatus::Available(path) => Ok(path),
            ToolStatus::NeedsInstall {
                version,
                artifact_name,
            } => self.install_version(&version, &artifact_name, target).await,
            ToolStatus::NeedsLatestInstall => {
                let latest_version = self.get_latest_version().await?;
                // We *do* know at this point that there do exist precompiled binaries
                let artifact_name = self.get_artifact_name(&latest_version).unwrap();
                self.install_version(&latest_version, &artifact_name, target)
                    .await
            }
        }
    }
    /// Checks if the user already has this tool installed. This should only be
    /// called if there are no precompiled binaries available of this tool
    /// for the user's platform. In that case, this will also warn the user
    /// if they've asked for a specific version that their own version might not
    /// be that (we don't bother trying to parse the version of their
    /// installed program).
    ///
    /// If there's nothing the user has installed, then this will return an
    /// error, and hence it should only be called after all other options
    /// have been exhausted.
    fn get_path_to_preinstalled(&self) -> Result<String, InstallError> {
        #[cfg(unix)]
        let shell_exec = "sh";
        #[cfg(windows)]
        let shell_exec = "powershell";
        #[cfg(unix)]
        let shell_param = "-c";
        #[cfg(windows)]
        let shell_param = "-command";

        let check_cmd = format!("{} --version", self.name); // Not exactly bulletproof, but it works!
        let res = Command::new(shell_exec)
            .args([shell_param, &check_cmd])
            .output();
        if let Err(err) = res {
            // Unlike `wasm-pack`, we don't try to install with `cargo install`, because
            // that's a little pointless to me (the user will still have to get
            // `wasm-opt` somehow...)
            //
            // TODO Installation script that can build manually on any platform
            Err(InstallError::ExternalToolUnavailable {
                tool: self.name.to_string(),
                source: err,
            })
        } else {
            // It works, so we don't need to install anything
            Ok(self.name.to_string())
        }
    }
    /// Installs the given version of the tool, returning the path to the final
    /// binary.
    async fn install_version(
        &self,
        version: &str,
        artifact_name: &str,
        target: &Path,
    ) -> Result<String, InstallError> {
        let url = format!(
            "https://github.com/{gh_repo}/releases/download/{version}/{artifact_name}.tar.gz",
            artifact_name = artifact_name,
            version = version,
            gh_repo = self.gh_repo
        );
        let dir_name = format!("{}-{}", self.name, version);
        let tar_name = format!("{}.tar.gz", &dir_name);
        let dir_path = target.join(&dir_name);
        let tar_path = target.join(&tar_name);

        // Deal with placeholders in the name to expect from the extracted directory
        let extracted_dir_name = self
            .extracted_dir_name
            .replace("%artifact_name", artifact_name)
            .replace("%version", version);

        // Download the tarball (source https://github.com/seanmonstar/reqwest/issues/1266#issuecomment-1106187437)
        // We do this by chunking to minimize memory usage (we're downloading fairly
        // large files!)
        let mut res = Client::new().get(url).send().await.map_err(|err| {
            InstallError::BinaryDownloadRequestFailed {
                source: err,
                tool: self.name.to_string(),
            }
        })?;
        let mut file = tokio::fs::File::create(&tar_path)
            .await
            .map_err(|err| InstallError::CreateToolDownloadDestFailed { source: err })?;
        while let Some(mut item) = res
            .chunk()
            .await
            .map_err(|err| InstallError::ChunkBinaryDownloadFailed { source: err })?
        {
            file.write_all_buf(item.borrow_mut())
                .await
                .map_err(|err| InstallError::WriteBinaryDownloadChunkFailed { source: err })?;
        }
        // Now unzip the tarball
        // TODO Async?
        let tar_gz = File::open(&tar_path)
            .map_err(|err| InstallError::CreateToolExtractDestFailed { source: err })?;
        let mut archive = Archive::new(GzDecoder::new(tar_gz));
        // We'll extract straight into `dist/tools/` and then rename the resulting
        // directory
        archive
            .unpack(target)
            .map_err(|err| InstallError::ToolExtractFailed {
                source: err,
                tool: self.name.to_string(),
            })?;

        // Now delete the original archive file
        fs::remove_file(&tar_path)
            .map_err(|err| InstallError::ArchiveDeletionFailed { source: err })?;
        // Finally, rename the extracted directory
        fs::rename(
            target.join(extracted_dir_name), // We extracted into the root of the target
            &dir_path,
        )
        .map_err(|err| InstallError::DirRenameFailed { source: err })?;

        // Return the path inside the directory we extracted
        Ok(dir_path
            .join(&self.final_path)
            .to_str()
            .unwrap()
            .to_string())
    }
    /// Gets the version of a specific package in `Cargo.lock`, assuming it has
    /// already been generated.
    fn get_pkg_version_from_lockfile(
        &self,
        lockfile: &Lockfile,
    ) -> Result<Option<String>, InstallError> {
        let version = lockfile
            .packages
            .iter()
            .find(|p| p.name.as_str() == self.name)
            .map(|p| p.version.to_string());
        Ok(version)
    }
}

/// A tool's status on-system.
pub enum ToolStatus {
    /// The tool needs to be installed.
    NeedsInstall {
        version: String,
        artifact_name: String,
    },
    /// The latest version of the tool needs to be determined from its repo and
    /// then installed.
    NeedsLatestInstall,
    /// The tool is already available at the attached path.
    Available(String),
}

/// The types of tools we can install.
pub enum ToolType {
    /// The `wasm-bindgen` CLI, used for producing final Wasm and JS artifacts.
    WasmBindgen,
    /// Binaryen's `wasm-opt` CLI, used for optimizing Wasm in release builds
    /// to achieve significant savings in bundle sizes.
    WasmOpt,
}
impl ToolType {
    /// Gets the tool's name.
    pub fn name(&self) -> String {
        match &self {
            Self::WasmBindgen => "wasm-bindgen",
            Self::WasmOpt => "wasm-opt",
        }
        .to_string()
    }
    /// Get's the path to the tool's binary inside the extracted directory
    /// from the downloaded archive.
    ///
    /// Note that the return value of this function is uncorrected for Windows.
    pub fn final_path(&self) -> String {
        match &self {
            Self::WasmBindgen => "wasm-bindgen",
            Self::WasmOpt => "bin/wasm-opt",
        }
        .to_string()
    }
    /// Gets the GitHub repo to install this tool from.
    pub fn gh_repo(&self) -> String {
        match &self {
            Self::WasmBindgen => "rustwasm/wasm-bindgen",
            Self::WasmOpt => "WebAssembly/binaryen",
        }
        .to_string()
    }
    /// Gets the name of the directory that will be extracted from the
    /// downloaded archive for this tool.
    ///
    /// This will return a `String` that might include placeholders for the
    /// version and downloaded artifact name.
    pub fn extracted_dir_name(&self) -> String {
        match &self {
            Self::WasmBindgen => "%artifact_name",
            Self::WasmOpt => "binaryen-%version",
        }
        .to_string()
    }
}