make gleam no_std compatible

.travis.yml

@@ -3,3 +3,7 @@ rust:
   - nightly
   - beta
   - stable
+
+script:
+  - cargo check --verbose --no-default-features
+  - cargo check --verbose --no-default-features --features="std"

Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "gleam"
-version = "0.13.1"
+version = "0.15.0"
 license = "Apache-2.0/MIT"
 authors = ["The Servo Project Developers"]
 build = "build.rs"
@@ -9,4 +9,8 @@ repository = "https://github.com/servo/gleam"
 description = "Generated OpenGL bindings and wrapper for Servo."
 
 [build-dependencies]
-gl_generator = "0.14"
+gl_generator = { version = "0.15", git = "https://github.com/fschutt/gl-rs", branch = "no_std", default-features = false }
+
+[features]
+default = ["std"]
+std = []

src/gl.rs

@@ -7,14 +7,19 @@
 // option. This file may not be copied, modified, or distributed
 // except according to those terms.
 
+extern crate core;
+extern crate alloc;
+
 use ffi;
-use std::ffi::{CStr, CString};
-use std::mem;
-use std::mem::size_of;
-use std::os::raw::{c_char, c_int, c_void};
-use std::ptr;
-use std::rc::Rc;
-use std::str;
+use core::mem;
+use core::mem::size_of;
+use ffi::__gl_imports::{c_void, c_int};
+use core::ptr;
+use alloc::rc::Rc;
+use alloc::vec::Vec;
+use alloc::string::String;
+use core::str;
+#[cfg(feature = "std")]
 use std::time::{Duration, Instant};
 
 pub use ffi::types::*;
@@ -104,6 +109,7 @@ macro_rules! declare_gl_apis {
             })+
         }
 
+        #[cfg(feature = "std")]
         impl<F: Fn(&str, Duration)> Gl for ProfilingGl<F> {
             $($(unsafe $($garbo)*)* fn $name(&self $(, $arg:$t)*) $(-> $retty)* {
                 let start = Instant::now();
@@ -783,12 +789,14 @@ impl<F: 'static + Fn(&dyn Gl, &str, GLenum)> ErrorReactingGl<F> {
 
 /// A wrapper around GL context that times each call and invokes the callback
 /// if the call takes longer than the threshold.
+#[cfg(feature = "std")]
 pub struct ProfilingGl<F> {
     gl: Rc<dyn Gl>,
     threshold: Duration,
     callback: F,
 }
 
+#[cfg(feature = "std")]
 impl<F: 'static + Fn(&str, Duration)> ProfilingGl<F> {
     pub fn wrap(fns: Rc<dyn Gl>, threshold: Duration, callback: F) -> Rc<dyn Gl> {
         Rc::new(ProfilingGl {

src/gl_fns.rs

@@ -7,6 +7,8 @@
 // option. This file may not be copied, modified, or distributed
 // except according to those terms.
 
+use utils::cstring_from_str;
+
 pub struct GlFns {
     ffi_gl_: GlFfi,
 }
@@ -399,7 +401,7 @@ impl Gl for GlFns {
     }
 
     fn bind_attrib_location(&self, program: GLuint, index: GLuint, name: &str) {
-        let c_string = CString::new(name).unwrap();
+        let c_string = cstring_from_str(name);
         unsafe {
             self.ffi_gl_
                 .BindAttribLocation(program, index, c_string.as_ptr())
@@ -421,15 +423,15 @@ impl Gl for GlFns {
     }
 
     fn get_uniform_block_index(&self, program: GLuint, name: &str) -> GLuint {
-        let c_string = CString::new(name).unwrap();
+        let c_string = cstring_from_str(name);
         unsafe {
             self.ffi_gl_
                 .GetUniformBlockIndex(program, c_string.as_ptr())
         }
     }
 
     fn get_uniform_indices(&self, program: GLuint, names: &[&str]) -> Vec<GLuint> {
-        let c_strings: Vec<CString> = names.iter().map(|n| CString::new(*n).unwrap()).collect();
+        let c_strings: Vec<Vec<u8>> = names.iter().map(|n| cstring_from_str(*n)).collect();
         let pointers: Vec<*const GLchar> = c_strings.iter().map(|string| string.as_ptr()).collect();
         let mut result = Vec::with_capacity(c_strings.len());
         unsafe {
@@ -1623,17 +1625,17 @@ impl Gl for GlFns {
     }
 
     fn get_attrib_location(&self, program: GLuint, name: &str) -> c_int {
-        let name = CString::new(name).unwrap();
+        let name = cstring_from_str(name);
         unsafe { self.ffi_gl_.GetAttribLocation(program, name.as_ptr()) }
     }
 
     fn get_frag_data_location(&self, program: GLuint, name: &str) -> c_int {
-        let name = CString::new(name).unwrap();
+        let name = cstring_from_str(name);
         unsafe { self.ffi_gl_.GetFragDataLocation(program, name.as_ptr()) }
     }
 
     fn get_uniform_location(&self, program: GLuint, name: &str) -> c_int {
-        let name = CString::new(name).unwrap();
+        let name = cstring_from_str(name);
         unsafe { self.ffi_gl_.GetUniformLocation(program, name.as_ptr()) }
     }
 
@@ -1786,10 +1788,9 @@ impl Gl for GlFns {
         unsafe {
             let llstr = self.ffi_gl_.GetString(which);
             if !llstr.is_null() {
-                return str::from_utf8_unchecked(CStr::from_ptr(llstr as *const c_char).to_bytes())
-                    .to_string();
+                cstr_from_ptr(llstr).to_string()
             } else {
-                return "".to_string();
+                String::new()
             }
         }
     }
@@ -1798,10 +1799,9 @@ impl Gl for GlFns {
         unsafe {
             let llstr = self.ffi_gl_.GetStringi(which, index);
             if !llstr.is_null() {
-                str::from_utf8_unchecked(CStr::from_ptr(llstr as *const c_char).to_bytes())
-                    .to_string()
+                cstr_from_ptr(llstr).to_string()
             } else {
-                "".to_string()
+                String::new()
             }
         }
     }
@@ -2098,7 +2098,7 @@ impl Gl for GlFns {
             return;
         }
 
-        let c_string = CString::new(name).unwrap();
+        let c_string = cstring_from_str(name);
 
         unsafe {
             self.ffi_gl_.BindFragDataLocationIndexed(
@@ -2115,7 +2115,7 @@ impl Gl for GlFns {
             return -1;
         }
 
-        let c_string = CString::new(name).unwrap();
+        let c_string = cstring_from_str(name);
 
         unsafe { self.ffi_gl_.GetFragDataIndex(program, c_string.as_ptr()) }
     }

src/gles_fns.rs

@@ -7,6 +7,9 @@
 // option. This file may not be copied, modified, or distributed
 // except according to those terms.
 
+use alloc::string::ToString;
+use utils::cstr_from_ptr;
+
 pub struct GlesFns {
     ffi_gl_: GlesFfi,
 }
@@ -414,7 +417,7 @@ impl Gl for GlesFns {
     }
 
     fn bind_attrib_location(&self, program: GLuint, index: GLuint, name: &str) {
-        let c_string = CString::new(name).unwrap();
+        let c_string = cstring_from_str(name);
         unsafe {
             self.ffi_gl_
                 .BindAttribLocation(program, index, c_string.as_ptr())
@@ -436,15 +439,15 @@ impl Gl for GlesFns {
     }
 
     fn get_uniform_block_index(&self, program: GLuint, name: &str) -> GLuint {
-        let c_string = CString::new(name).unwrap();
+        let c_string = cstring_from_str(name);
         unsafe {
             self.ffi_gl_
                 .GetUniformBlockIndex(program, c_string.as_ptr())
         }
     }
 
     fn get_uniform_indices(&self, program: GLuint, names: &[&str]) -> Vec<GLuint> {
-        let c_strings: Vec<CString> = names.iter().map(|n| CString::new(*n).unwrap()).collect();
+        let c_strings: Vec<Vec<u8>> = names.iter().map(|n| cstring_from_str(*n)).collect();
         let pointers: Vec<*const GLchar> = c_strings.iter().map(|string| string.as_ptr()).collect();
         let mut result = Vec::with_capacity(c_strings.len());
         unsafe {
@@ -1622,7 +1625,7 @@ impl Gl for GlesFns {
     }
 
     fn get_attrib_location(&self, program: GLuint, name: &str) -> c_int {
-        let name = CString::new(name).unwrap();
+        let name = cstring_from_str(name);
         unsafe { self.ffi_gl_.GetAttribLocation(program, name.as_ptr()) }
     }
 
@@ -1632,7 +1635,7 @@ impl Gl for GlesFns {
     }
 
     fn get_uniform_location(&self, program: GLuint, name: &str) -> c_int {
-        let name = CString::new(name).unwrap();
+        let name = cstring_from_str(name);
         unsafe { self.ffi_gl_.GetUniformLocation(program, name.as_ptr()) }
     }
 
@@ -1776,10 +1779,9 @@ impl Gl for GlesFns {
         unsafe {
             let llstr = self.ffi_gl_.GetString(which);
             if !llstr.is_null() {
-                return str::from_utf8_unchecked(CStr::from_ptr(llstr as *const c_char).to_bytes())
-                    .to_string();
+                cstr_from_ptr(llstr).to_string()
             } else {
-                return "".to_string();
+                String::new()
             }
         }
     }
@@ -1788,10 +1790,9 @@ impl Gl for GlesFns {
         unsafe {
             let llstr = self.ffi_gl_.GetStringi(which, index);
             if !llstr.is_null() {
-                str::from_utf8_unchecked(CStr::from_ptr(llstr as *const c_char).to_bytes())
-                    .to_string()
+                cstr_from_ptr(llstr).to_string()
             } else {
-                "".to_string()
+                String::new()
             }
         }
     }

src/lib.rs

@@ -7,9 +7,13 @@
 // option. This file may not be copied, modified, or distributed
 // except according to those terms.
 
+#![cfg_attr(not(feature = "std"), no_std)]
 #![crate_name = "gleam"]
 #![crate_type = "lib"]
 
+#[macro_use]
+extern crate alloc;
+
 pub mod gl;
 
 mod ffi {
@@ -23,3 +27,28 @@ mod ffi_gl {
 mod ffi_gles {
     include!(concat!(env!("OUT_DIR"), "/gles_bindings.rs"));
 }
+
+pub(crate) mod utils {
+    use alloc::vec::Vec;
+
+    /// CString is not available on libcore, but all that CString does
+    /// is to cast the string to bytes, then append a "0" at the end.
+    pub fn cstring_from_str(s: &str) -> Vec<u8> { let mut v: Vec<u8> = s.into(); v.push(0); v }
+    /// no-std port of Cstr::from_ptr
+    pub unsafe fn cstr_from_ptr<'a>(ptr: *const crate::ffi::__gl_imports::c_uchar) -> &'a str {
+
+        #[inline]
+        unsafe fn strlen(mut s: *const crate::ffi::__gl_imports::c_uchar) -> usize {
+            let mut result = 0;
+            while *s != 0 {
+                s = s.offset(1);
+                result += 1;
+            }
+            result
+        }
+
+        let len = strlen(ptr);
+        let ptr = ptr as *const u8; // c_char is always one byte, safe cast
+        core::str::from_utf8_unchecked(core::slice::from_raw_parts(ptr, len as usize + 1))
+    }
+}