gasm 0.0.1

Utility for building Gear programs
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

// This file is part of Gear.

// Copyright (C) 2022 Gear Technologies Inc.
// SPDX-License-Identifier: GPL-3.0-or-later WITH Classpath-exception-2.0

// This program is free software: you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.

// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU General Public License for more details.

// You should have received a copy of the GNU General Public License
// along with this program. If not, see <https://www.gnu.org/licenses/>.

use anyhow::{Context, Result};
use std::{
    env, fs,
    path::{Path, PathBuf},
};
use toml::value::Table;

use crate::{
    crate_info::CrateInfo,
    optimize::{OptType, Optimizer},
};

/// Temporary project generated to build a WASM output.
///
/// This project is required due to the cargo locking during build.
pub struct WasmProject {
    original_dir: PathBuf,
    out_dir: PathBuf,
    target_dir: PathBuf,
    wasm_target_dir: PathBuf,
    file_base_name: Option<String>,
    profile: String,
}

impl WasmProject {
    /// Create a new `WasmProject`.
    pub fn new() -> Self {
        let original_dir: PathBuf = env::var("CARGO_MANIFEST_DIR")
            .expect("`CARGO_MANIFEST_DIR` is always set in build scripts")
            .into();

        let out_dir: PathBuf = env::var("OUT_DIR")
            .expect("`OUT_DIR` is always set in build scripts")
            .into();

        let profile = out_dir
            .components()
            .rev()
            .take_while(|c| c.as_os_str() != "target")
            .collect::<Vec<_>>()
            .into_iter()
            .rev()
            .take_while(|c| c.as_os_str() != "build")
            .last()
            .expect("Path should have subdirs in the `target` dir")
            .as_os_str()
            .to_string_lossy()
            .into();

        let mut target_dir = out_dir.clone();
        while target_dir.pop() {
            if target_dir.ends_with("target") {
                break;
            }
        }

        let mut wasm_target_dir = target_dir.clone();
        wasm_target_dir.push("wasm32-unknown-unknown");
        wasm_target_dir.push(&profile);

        target_dir.push("wasm-projects");
        target_dir.push(&profile);

        WasmProject {
            original_dir,
            out_dir,
            target_dir,
            wasm_target_dir,
            file_base_name: None,
            profile,
        }
    }

    /// Return the path to the temporary generated `Cargo.toml`.
    pub fn manifest_path(&self) -> PathBuf {
        self.out_dir.join("Cargo.toml")
    }

    /// Return the path to the target directory.
    pub fn target_dir(&self) -> PathBuf {
        self.target_dir.clone()
    }

    /// Return the profile name based on the `OUT_DIR` path.
    pub fn profile(&self) -> &str {
        &self.profile
    }

    /// Generate a temporary cargo project that includes the original package as a dependency.
    pub fn generate(&mut self) -> Result<()> {
        let original_manifest = self.original_dir.join("Cargo.toml");
        let crate_info = CrateInfo::from_manifest(&original_manifest)?;
        self.file_base_name = Some(crate_info.snake_case_name.clone());

        let mut package = Table::new();
        package.insert("name".into(), format!("{}-wasm", &crate_info.name).into());
        package.insert("version".into(), crate_info.version.into());
        package.insert("edition".into(), "2021".into());

        let mut lib = Table::new();
        lib.insert("name".into(), crate_info.snake_case_name.into());
        lib.insert("crate-type".into(), vec!["cdylib".to_string()].into());

        let mut release_profile = Table::new();
        release_profile.insert("lto".into(), true.into());
        release_profile.insert("opt-level".into(), "s".into());

        let mut profile = Table::new();
        profile.insert("dev".into(), release_profile.clone().into());
        profile.insert("release".into(), release_profile.into());

        let mut crate_package = Table::new();
        crate_package.insert("package".into(), crate_info.name.into());
        crate_package.insert(
            "path".into(),
            self.original_dir.display().to_string().into(),
        );
        crate_package.insert("default-features".into(), false.into());

        let mut dependencies = Table::new();
        dependencies.insert("orig-project".into(), crate_package.into());

        let mut features = Table::new();
        for feature in crate_info.features.keys() {
            if feature != "default" {
                features.insert(
                    feature.into(),
                    vec![format!("orig-project/{feature}")].into(),
                );
            }
        }

        let mut cargo_toml = Table::new();
        cargo_toml.insert("package".into(), package.into());
        cargo_toml.insert("lib".into(), lib.into());
        cargo_toml.insert("dependencies".into(), dependencies.into());
        cargo_toml.insert("profile".into(), profile.into());
        cargo_toml.insert("features".into(), features.into());
        cargo_toml.insert("workspace".into(), Table::new().into());

        fs::write(self.manifest_path(), toml::to_string_pretty(&cargo_toml)?)?;

        let src_dir = self.out_dir.join("src");
        fs::create_dir_all(&src_dir)?;
        fs::write(
            src_dir.join("lib.rs"),
            "#![no_std] pub use orig_project::*;",
        )?;

        // Copy original `Cargo.lock` if any
        let from_lock = self.original_dir.join("Cargo.lock");
        let to_lock = self.out_dir.join("Cargo.lock");
        let _ = fs::copy(from_lock, to_lock);

        Ok(())
    }

    /// Post-processing after the WASM binary has been built.
    ///
    /// - Copy WASM binary from `OUT_DIR` to `target/wasm32-unknown-unknown/<profile>`
    /// - Generate optimized and metadata WASM binaries from the built program
    /// - Generate `wasm_binary.rs` source file in `OUT_DIR`
    pub fn postprocess(&self) -> Result<()> {
        let file_base_name = self
            .file_base_name
            .as_ref()
            .expect("Run `WasmProject::create_project()` first");

        let from_path = self
            .target_dir
            .join(format!("wasm32-unknown-unknown/{}", self.profile))
            .join(format!("{}.wasm", &file_base_name));

        fs::create_dir_all(&self.target_dir)?;
        fs::create_dir_all(&self.wasm_target_dir)?;

        let [to_path, to_opt_path, to_meta_path] = [".wasm", ".opt.wasm", ".meta.wasm"]
            .map(|ext| self.wasm_target_dir.join([file_base_name, ext].concat()));

        // Optimize source.
        fs::copy(&from_path, &to_path).context("unable to copy WASM file")?;
        let _ = crate::optimize::optimize_wasm(to_path.clone(), "s", false);

        // Generate wasm binaries
        Self::generate_wasm(from_path, &to_opt_path, &to_meta_path)?;

        let wasm_binary_path = self.original_dir.join(".binpath");

        let mut relative_path = pathdiff::diff_paths(&to_path, &self.original_dir)
            .expect("Unable to calculate relative path");

        // Remove extension
        relative_path.set_extension("");

        fs::write(wasm_binary_path, format!("{}", relative_path.display()))
            .context("unable to write `.binpath`")?;

        let wasm_binary_rs = self.out_dir.join("wasm_binary.rs");
        fs::write(
            wasm_binary_rs,
            format!(
                r#"#[allow(unused)]
pub const WASM_BINARY: &[u8] = include_bytes!("{}");
#[allow(unused)]
pub const WASM_BINARY_OPT: &[u8] = include_bytes!("{}");
#[allow(unused)]
pub const WASM_BINARY_META: &[u8] = include_bytes!("{}");
"#,
                display_path(to_path),
                display_path(to_opt_path),
                display_path(to_meta_path),
            ),
        )
        .context("unable to write `wasm_binary.rs`")?;

        Ok(())
    }

    fn generate_wasm(from: PathBuf, to_opt: &Path, to_meta: &Path) -> Result<()> {
        let mut optimizer = Optimizer::new(from)?;
        optimizer.insert_stack_and_export();
        optimizer.strip_custom_sections();

        // Generate *.opt.wasm.
        let opt = optimizer.optimize(OptType::Opt)?;
        fs::write(to_opt, opt)?;

        // Generate *.meta.wasm.
        let meta = optimizer.optimize(OptType::Meta)?;
        fs::write(to_meta, meta)?;

        Ok(())
    }
}

// Windows has path like `path\to\somewhere` which is incorrect for `include_*` Rust's macros
fn display_path(path: PathBuf) -> String {
    path.display().to_string().replace('\\', "/")
}