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
use core::marker::PhantomData;

use crate::common::{DebugInfoOffset, Format};
use crate::read::{parse_debug_info_offset, Error, Reader, ReaderOffset, Result, UnitOffset};

// The various "Accelerated Access" sections (DWARF standard v4 Section 6.1) all have
// similar structures. They consist of a header with metadata and an offset into the
// .debug_info section for the entire compilation unit, and a series
// of following entries that list addresses (for .debug_aranges) or names
// (for .debug_pubnames and .debug_pubtypes) that are covered.
//
// Because these three tables all have similar structures, we abstract out some of
// the parsing mechanics.

pub trait LookupParser<R: Reader> {
    /// The type of the produced header.
    type Header;
    /// The type of the produced entry.
    type Entry;

    /// Parse a header from `input`. Returns a tuple of `input` sliced to contain just the entries
    /// corresponding to this header (without the header itself), and the parsed representation of
    /// the header itself.
    fn parse_header(input: &mut R) -> Result<(R, Self::Header)>;

    /// Parse a single entry from `input`. Returns either a parsed representation of the entry
    /// or None if `input` is exhausted.
    fn parse_entry(input: &mut R, header: &Self::Header) -> Result<Option<Self::Entry>>;
}

#[derive(Clone, Debug)]
pub struct DebugLookup<R, Parser>
where
    R: Reader,
    Parser: LookupParser<R>,
{
    input_buffer: R,
    phantom: PhantomData<Parser>,
}

impl<R, Parser> From<R> for DebugLookup<R, Parser>
where
    R: Reader,
    Parser: LookupParser<R>,
{
    fn from(input_buffer: R) -> Self {
        DebugLookup {
            input_buffer,
            phantom: PhantomData,
        }
    }
}

impl<R, Parser> DebugLookup<R, Parser>
where
    R: Reader,
    Parser: LookupParser<R>,
{
    pub fn items(&self) -> LookupEntryIter<R, Parser> {
        LookupEntryIter {
            current_set: None,
            remaining_input: self.input_buffer.clone(),
        }
    }

    pub fn reader(&self) -> &R {
        &self.input_buffer
    }
}

#[derive(Clone, Debug)]
pub struct LookupEntryIter<R, Parser>
where
    R: Reader,
    Parser: LookupParser<R>,
{
    current_set: Option<(R, Parser::Header)>, // Only none at the very beginning and end.
    remaining_input: R,
}

impl<R, Parser> LookupEntryIter<R, Parser>
where
    R: Reader,
    Parser: LookupParser<R>,
{
    /// Advance the iterator and return the next entry.
    ///
    /// Returns the newly parsed entry as `Ok(Some(Parser::Entry))`. Returns
    /// `Ok(None)` when iteration is complete and all entries have already been
    /// parsed and yielded. If an error occurs while parsing the next entry,
    /// then this error is returned as `Err(e)`, and all subsequent calls return
    /// `Ok(None)`.
    ///
    /// Can be [used with `FallibleIterator`](./index.html#using-with-fallibleiterator).
    pub fn next(&mut self) -> Result<Option<Parser::Entry>> {
        loop {
            if let Some((ref mut input, ref header)) = self.current_set {
                if !input.is_empty() {
                    match Parser::parse_entry(input, header) {
                        Ok(Some(entry)) => return Ok(Some(entry)),
                        Ok(None) => {}
                        Err(e) => {
                            input.empty();
                            self.remaining_input.empty();
                            return Err(e);
                        }
                    }
                }
            }
            if self.remaining_input.is_empty() {
                self.current_set = None;
                return Ok(None);
            }
            match Parser::parse_header(&mut self.remaining_input) {
                Ok(set) => {
                    self.current_set = Some(set);
                }
                Err(e) => {
                    self.current_set = None;
                    self.remaining_input.empty();
                    return Err(e);
                }
            }
        }
    }
}

#[derive(Debug, Clone, PartialEq, Eq)]
pub struct PubStuffHeader<T = usize> {
    format: Format,
    length: T,
    version: u16,
    unit_offset: DebugInfoOffset<T>,
    unit_length: T,
}

pub trait PubStuffEntry<R: Reader> {
    fn new(
        die_offset: UnitOffset<R::Offset>,
        name: R,
        unit_header_offset: DebugInfoOffset<R::Offset>,
    ) -> Self;
}

#[derive(Clone, Debug)]
pub struct PubStuffParser<R, Entry>
where
    R: Reader,
    Entry: PubStuffEntry<R>,
{
    // This struct is never instantiated.
    phantom: PhantomData<(R, Entry)>,
}

impl<R, Entry> LookupParser<R> for PubStuffParser<R, Entry>
where
    R: Reader,
    Entry: PubStuffEntry<R>,
{
    type Header = PubStuffHeader<R::Offset>;
    type Entry = Entry;

    /// Parse an pubthings set header. Returns a tuple of the
    /// pubthings to be parsed for this set, and the newly created PubThingHeader struct.
    fn parse_header(input: &mut R) -> Result<(R, Self::Header)> {
        let (length, format) = input.read_initial_length()?;
        let mut rest = input.split(length)?;

        let version = rest.read_u16()?;
        if version != 2 {
            return Err(Error::UnknownVersion(u64::from(version)));
        }

        let unit_offset = parse_debug_info_offset(&mut rest, format)?;
        let unit_length = rest.read_length(format)?;

        let header = PubStuffHeader {
            format,
            length,
            version,
            unit_offset,
            unit_length,
        };
        Ok((rest, header))
    }

    /// Parse a single pubthing. Return `None` for the null pubthing, `Some` for an actual pubthing.
    fn parse_entry(input: &mut R, header: &Self::Header) -> Result<Option<Self::Entry>> {
        let offset = input.read_offset(header.format)?;
        if offset.into_u64() == 0 {
            input.empty();
            Ok(None)
        } else {
            let name = input.read_null_terminated_slice()?;
            Ok(Some(Self::Entry::new(
                UnitOffset(offset),
                name,
                header.unit_offset,
            )))
        }
    }
}