/src/wasm-tools/crates/wasmparser/src/readers/element_section.rs

Source (jump to first uncovered line)
/* Copyright 2018 Mozilla Foundation
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

use super::{
    BinaryReader, BinaryReaderError, InitExpr, Range, Result, SectionIteratorLimited,
    SectionReader, SectionWithLimitedItems, Type,
};
use crate::{ExternalKind, Operator};

#[derive(Clone)]
pub struct Element<'a> {
    pub kind: ElementKind<'a>,
    pub items: ElementItems<'a>,
    pub ty: Type,
}

#[derive(Clone)]
pub enum ElementKind<'a> {
    Passive,
    Active {
        table_index: u32,
        init_expr: InitExpr<'a>,
    },
    Declared,
}

#[derive(Debug, Copy, Clone)]
pub struct ElementItems<'a> {
    exprs: bool,
    offset: usize,
    data: &'a [u8],
}

#[derive(Debug)]
pub enum ElementItem {
    Null(Type),
    Func(u32),
}

impl<'a> ElementItems<'a> {
    pub fn get_items_reader<'b>(&self) -> Result<ElementItemsReader<'b>>
    where
        'a: 'b,
    {
        ElementItemsReader::new(self.data, self.offset, self.exprs)
    }
}

pub struct ElementItemsReader<'a> {
    reader: BinaryReader<'a>,
    count: u32,
    exprs: bool,
}

impl<'a> ElementItemsReader<'a> {
    pub fn new(data: &[u8], offset: usize, exprs: bool) -> Result<ElementItemsReader> {
        let mut reader = BinaryReader::new_with_offset(data, offset);
        let count = reader.read_var_u32()?;
        Ok(ElementItemsReader {
            reader,
            count,
            exprs,
        })
    }

    pub fn original_position(&self) -> usize {
        self.reader.original_position()
    }

    pub fn get_count(&self) -> u32 {
        self.count
    }

    pub fn uses_exprs(&self) -> bool {
        self.exprs
    }

    pub fn read(&mut self) -> Result<ElementItem> {
        if self.exprs {
            let offset = self.reader.original_position();
            let ret = match self.reader.read_operator()? {
                Operator::RefNull { ty } => ElementItem::Null(ty),
                Operator::RefFunc { function_index } => ElementItem::Func(function_index),
                _ => return Err(BinaryReaderError::new("invalid passive segment", offset)),
            };
            match self.reader.read_operator()? {
                Operator::End => {}
                _ => return Err(BinaryReaderError::new("invalid passive segment", offset)),
            }
            Ok(ret)
        } else {
            self.reader.read_var_u32().map(ElementItem::Func)
        }
    }
}

impl<'a> IntoIterator for ElementItemsReader<'a> {
    type Item = Result<ElementItem>;
    type IntoIter = ElementItemsIterator<'a>;
    fn into_iter(self) -> Self::IntoIter {
        let count = self.count;
        ElementItemsIterator {
            reader: self,
            left: count,
            err: false,
        }
    }
}

pub struct ElementItemsIterator<'a> {
    reader: ElementItemsReader<'a>,
    left: u32,
    err: bool,
}

impl<'a> Iterator for ElementItemsIterator<'a> {
    type Item = Result<ElementItem>;
    fn next(&mut self) -> Option<Self::Item> {
        if self.err || self.left == 0 {
            return None;
        }
        let result = self.reader.read();
        self.err = result.is_err();
        self.left -= 1;
        Some(result)
    }
    fn size_hint(&self) -> (usize, Option<usize>) {
        let count = self.reader.get_count() as usize;
        (count, Some(count))
    }
}

#[derive(Clone)]
pub struct ElementSectionReader<'a> {
    reader: BinaryReader<'a>,
    count: u32,
}

impl<'a> ElementSectionReader<'a> {
    pub fn new(data: &'a [u8], offset: usize) -> Result<ElementSectionReader<'a>> {
        let mut reader = BinaryReader::new_with_offset(data, offset);
        let count = reader.read_var_u32()?;
        Ok(ElementSectionReader { reader, count })
    }

    pub fn original_position(&self) -> usize {
        self.reader.original_position()
    }

    pub fn get_count(&self) -> u32 {
        self.count
    }

    /// Reads content of the element section.
    ///
    /// # Examples
    ///
    /// ```no_run
    /// # let data: &[u8] = &[];
    /// use wasmparser::{ElementSectionReader, ElementKind};
    /// let mut element_reader = ElementSectionReader::new(data, 0).unwrap();
    /// for _ in 0..element_reader.get_count() {
    ///     let element = element_reader.read().expect("element");
    ///     if let ElementKind::Active { init_expr, .. } = element.kind {
    ///         let mut init_expr_reader = init_expr.get_binary_reader();
    ///         let op = init_expr_reader.read_operator().expect("op");
    ///         println!("Init const: {:?}", op);
    ///     }
    ///     let mut items_reader = element.items.get_items_reader().expect("items reader");
    ///     for _ in 0..items_reader.get_count() {
    ///         let item = items_reader.read().expect("item");
    ///         println!("  Item: {:?}", item);
    ///     }
    /// }
    /// ```
    pub fn read<'b>(&mut self) -> Result<Element<'b>>
    where
        'a: 'b,
    {
        let flags = self.reader.read_var_u32()?;
        if (flags & !0b111) != 0 {
            return Err(BinaryReaderError::new(
                "invalid flags byte in element segment",
                self.reader.original_position() - 1,
            ));
        }
        let kind = if flags & 0b001 != 0 {
            if flags & 0b010 != 0 {
                ElementKind::Declared
            } else {
                ElementKind::Passive
            }
        } else {
            let table_index = if flags & 0b010 == 0 {
                0
            } else {
                self.reader.read_var_u32()?
            };
            let init_expr = {
                let expr_offset = self.reader.position;
                self.reader.skip_init_expr()?;
                let data = &self.reader.buffer[expr_offset..self.reader.position];
                InitExpr::new(data, self.reader.original_offset + expr_offset)
            };
            ElementKind::Active {
                table_index,
                init_expr,
            }
        };
        let exprs = flags & 0b100 != 0;
        let ty = if flags & 0b011 != 0 {
            if exprs {
                self.reader.read_type()?
            } else {
                match self.reader.read_external_kind()? {
                    ExternalKind::Function => Type::FuncRef,
                    _ => {
                        return Err(BinaryReaderError::new(
                            "only the function external type is supported in elem segment",
                            self.reader.original_position() - 1,
                        ));
                    }
                }
            }
        } else {
            Type::FuncRef
        };
        let data_start = self.reader.position;
        let items_count = self.reader.read_var_u32()?;
        if exprs {
            for _ in 0..items_count {
                self.reader.skip_init_expr()?;
            }
        } else {
            for _ in 0..items_count {
                self.reader.skip_var_32()?;
            }
        }
        let data_end = self.reader.position;
        let items = ElementItems {
            offset: self.reader.original_offset + data_start,
            data: &self.reader.buffer[data_start..data_end],
            exprs,
        };
        Ok(Element { kind, items, ty })
    }
}

impl<'a> SectionReader for ElementSectionReader<'a> {
    type Item = Element<'a>;
    fn read(&mut self) -> Result<Self::Item> {
        ElementSectionReader::read(self)
    }
    fn eof(&self) -> bool {
        self.reader.eof()
    }
    fn original_position(&self) -> usize {
        ElementSectionReader::original_position(self)
    }
    fn range(&self) -> Range {
        self.reader.range()
    }
}

impl<'a> SectionWithLimitedItems for ElementSectionReader<'a> {
    fn get_count(&self) -> u32 {
        ElementSectionReader::get_count(self)
    }
}

impl<'a> IntoIterator for ElementSectionReader<'a> {
    type Item = Result<Element<'a>>;
    type IntoIter = SectionIteratorLimited<ElementSectionReader<'a>>;

    fn into_iter(self) -> Self::IntoIter {
        SectionIteratorLimited::new(self)
    }
}

Coverage Report

Created: 2021-03-22 08:29

Line	Count	Source (jump to first uncovered line)
1		/* Copyright 2018 Mozilla Foundation
2		*
3		* Licensed under the Apache License, Version 2.0 (the "License");
4		* you may not use this file except in compliance with the License.
5		* You may obtain a copy of the License at
6		*
7		* http://www.apache.org/licenses/LICENSE-2.0
8		*
9		* Unless required by applicable law or agreed to in writing, software
10		* distributed under the License is distributed on an "AS IS" BASIS,
11		* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
12		* See the License for the specific language governing permissions and
13		* limitations under the License.
14		*/
15
16		use super::{
17		BinaryReader, BinaryReaderError, InitExpr, Range, Result, SectionIteratorLimited,
18		SectionReader, SectionWithLimitedItems, Type,
19		};
20		use crate::{ExternalKind, Operator};
21
22	0	#[derive(Clone)]
23		pub struct Element<'a> {
24		pub kind: ElementKind<'a>,
25		pub items: ElementItems<'a>,
26		pub ty: Type,
27		}
28
29	0	#[derive(Clone)]
30		pub enum ElementKind<'a> {
31		Passive,
32		Active {
33		table_index: u32,
34		init_expr: InitExpr<'a>,
35		},
36		Declared,
37		}
38
39	0	#[derive(Debug, Copy, Clone)]
40		pub struct ElementItems<'a> {
41		exprs: bool,
42		offset: usize,
43		data: &'a [u8],
44		}
45
46		#[derive(Debug)]
47		pub enum ElementItem {
48		Null(Type),
49		Func(u32),
50		}
51
52		impl<'a> ElementItems<'a> {
53	860k	pub fn get_items_reader<'b>(&self) -> Result<ElementItemsReader<'b>>
54	860k	where
55	860k	'a: 'b,
56	860k	{
57	860k	ElementItemsReader::new(self.data, self.offset, self.exprs)
58	860k	}
59		}
60
61		pub struct ElementItemsReader<'a> {
62		reader: BinaryReader<'a>,
63		count: u32,
64		exprs: bool,
65		}
66
67		impl<'a> ElementItemsReader<'a> {
68	860k	pub fn new(data: &[u8], offset: usize, exprs: bool) -> Result<ElementItemsReader> {
69	860k	let mut reader = BinaryReader::new_with_offset(data, offset);
70	860k	let count = reader.read_var_u32()?;
71	860k	Ok(ElementItemsReader {
72	860k	reader,
73	860k	count,
74	860k	exprs,
75	860k	})
76	860k	}
77
78	36.7M	pub fn original_position(&self) -> usize {
79	36.7M	self.reader.original_position()
80	36.7M	}
81
82	1.60M	pub fn get_count(&self) -> u32 {
83	1.60M	self.count
84	1.60M	}
85
86	2.02M	pub fn uses_exprs(&self) -> bool {
87	2.02M	self.exprs
88	2.02M	}
89
90	38.6M	pub fn read(&mut self) -> Result<ElementItem> {
91	38.6M	if self.exprs {
92	35.2M	let offset = self.reader.original_position();
93	35.2M	let ret = match self.reader.read_operator()? {
94	35.2M	Operator::RefNull { ty } => ElementItem::Null(ty),
95	41.0k	Operator::RefFunc { function_index } => ElementItem::Func(function_index),
96	23	_ => return Err(BinaryReaderError::new("invalid passive segment", offset)),
97		};
98	35.2M	match self.reader.read_operator()? {
99	35.2M	Operator::End => {}
100	14	_ => return Err(BinaryReaderError::new("invalid passive segment", offset)),
101		}
102	35.2M	Ok(ret)
103		} else {
104	3.34M	self.reader.read_var_u32().map(ElementItem::Func)
105		}
106	38.6M	}
107		}
108
109		impl<'a> IntoIterator for ElementItemsReader<'a> {
110		type Item = Result<ElementItem>;
111		type IntoIter = ElementItemsIterator<'a>;
112		fn into_iter(self) -> Self::IntoIter {
113		let count = self.count;
114		ElementItemsIterator {
115		reader: self,
116		left: count,
117		err: false,
118		}
119		}
120		}
121
122		pub struct ElementItemsIterator<'a> {
123		reader: ElementItemsReader<'a>,
124		left: u32,
125		err: bool,
126		}
127
128		impl<'a> Iterator for ElementItemsIterator<'a> {
129		type Item = Result<ElementItem>;
130	0	fn next(&mut self) -> Option<Self::Item> {
131	0	if self.err \|\| self.left == 0 {
132	0	return None;
133	0	}
134	0	let result = self.reader.read();
135	0	self.err = result.is_err();
136	0	self.left -= 1;
137	0	Some(result)
138	0	}
139		fn size_hint(&self) -> (usize, Option<usize>) {
140		let count = self.reader.get_count() as usize;
141		(count, Some(count))
142		}
143		}
144
145	151k	#[derive(Clone)]
146		pub struct ElementSectionReader<'a> {
147		reader: BinaryReader<'a>,
148		count: u32,
149		}
150
151		impl<'a> ElementSectionReader<'a> {
152	8.33M	pub fn new(data: &'a [u8], offset: usize) -> Result<ElementSectionReader<'a>> {
153	8.33M	let mut reader = BinaryReader::new_with_offset(data, offset);
154	8.33M	let count = reader.read_var_u32()?;
155	8.33M	Ok(ElementSectionReader { reader, count })
156	8.33M	}
157
158	748k	pub fn original_position(&self) -> usize {
159	748k	self.reader.original_position()
160	748k	}
161
162	4.14M	pub fn get_count(&self) -> u32 {
163	4.14M	self.count
164	4.14M	}
165
166		/// Reads content of the element section.
167		///
168		/// # Examples
169		///
170		/// ```no_run
171		/// # let data: &[u8] = &[];
172		/// use wasmparser::{ElementSectionReader, ElementKind};
173		/// let mut element_reader = ElementSectionReader::new(data, 0).unwrap();
174		/// for _ in 0..element_reader.get_count() {
175		/// let element = element_reader.read().expect("element");
176		/// if let ElementKind::Active { init_expr, .. } = element.kind {
177		/// let mut init_expr_reader = init_expr.get_binary_reader();
178		/// let op = init_expr_reader.read_operator().expect("op");
179		/// println!("Init const: {:?}", op);
180		/// }
181		/// let mut items_reader = element.items.get_items_reader().expect("items reader");
182		/// for _ in 0..items_reader.get_count() {
183		/// let item = items_reader.read().expect("item");
184		/// println!(" Item: {:?}", item);
185		/// }
186		/// }
187		/// ```
188	870k	pub fn read<'b>(&mut self) -> Result<Element<'b>>
189	870k	where
190	870k	'a: 'b,
191	870k	{
192	870k	let flags = self.reader.read_var_u32()?;
193	869k	if (flags & !0b111) != 0 {
194	873	return Err(BinaryReaderError::new(
195	873	"invalid flags byte in element segment",
196	873	self.reader.original_position() - 1,
197	873	));
198	868k	}
199	868k	let kind = if flags & 0b001 != 0 {
200	558k	if flags & 0b010 != 0 {
201	213k	ElementKind::Declared
202		} else {
203	345k	ElementKind::Passive
204		}
205		} else {
206	310k	let table_index = if flags & 0b010 == 0 {
207	242k	0
208		} else {
209	67.2k	self.reader.read_var_u32()?
210		};
211	303k	let init_expr = {
212	310k	let expr_offset = self.reader.position;
213	310k	self.reader.skip_init_expr()?;
214	303k	let data = &self.reader.buffer[expr_offset..self.reader.position];
215	303k	InitExpr::new(data, self.reader.original_offset + expr_offset)
216	303k	};
217	303k	ElementKind::Active {
218	303k	table_index,
219	303k	init_expr,
220	303k	}
221		};
222	862k	let exprs = flags & 0b100 != 0;
223	862k	let ty = if flags & 0b011 != 0 {
224	625k	if exprs {
225	579k	self.reader.read_type()?
226		} else {
227	46.3k	match self.reader.read_external_kind()? {
228	46.1k	ExternalKind::Function => Type::FuncRef,
229		_ => {
230	31	return Err(BinaryReaderError::new(
231	31	"only the function external type is supported in elem segment",
232	31	self.reader.original_position() - 1,
233	31	));
234		}
235		}
236		}
237		} else {
238	236k	Type::FuncRef
239		};
240	862k	let data_start = self.reader.position;
241	862k	let items_count = self.reader.read_var_u32()?;
242	862k	if exprs {
243	35.2M	for _ in 0..items_count {
244	35.2M	self.reader.skip_init_expr()?;
245		}
246		} else {
247	3.36M	for _ in 0..items_count {
248	3.36M	self.reader.skip_var_32()?;
249		}
250		}
251	861k	let data_end = self.reader.position;
252	861k	let items = ElementItems {
253	861k	offset: self.reader.original_offset + data_start,
254	861k	data: &self.reader.buffer[data_start..data_end],
255	861k	exprs,
256	861k	};
257	861k	Ok(Element { kind, items, ty })
258	870k	}
259		}
260
261		impl<'a> SectionReader for ElementSectionReader<'a> {
262		type Item = Element<'a>;
263	870k	fn read(&mut self) -> Result<Self::Item> {
264	870k	ElementSectionReader::read(self)
265	870k	}
266	4.13M	fn eof(&self) -> bool {
267	4.13M	self.reader.eof()
268	4.13M	}
269	748k	fn original_position(&self) -> usize {
270	748k	ElementSectionReader::original_position(self)
271	748k	}
272	299k	fn range(&self) -> Range {
273	299k	self.reader.range()
274	299k	}
275		}
276
277		impl<'a> SectionWithLimitedItems for ElementSectionReader<'a> {
278	4.14M	fn get_count(&self) -> u32 {
279	4.14M	ElementSectionReader::get_count(self)
280	4.14M	}
281		}
282
283		impl<'a> IntoIterator for ElementSectionReader<'a> {
284		type Item = Result<Element<'a>>;
285		type IntoIter = SectionIteratorLimited<ElementSectionReader<'a>>;
286
287	3.99M	fn into_iter(self) -> Self::IntoIter {
288	3.99M	SectionIteratorLimited::new(self)
289	3.99M	}
290		}