Crate jvm_hprof

A library for parsing hprof files.

See parse_hprof to get started, or see the examples in the repo.

Examples

Iterating across all records to count how many of each record type there are (adapted from the analyze_hprof example’s record-counts subcommand):

use std::{fs, collections};
use jvm_hprof::{Hprof, parse_hprof, RecordTag, EnumIterable};

fn count_records(file: fs::File) {
    let memmap = unsafe { memmap::MmapOptions::new().map(&file) }.unwrap();

    let hprof: Hprof = parse_hprof(&memmap[..]).unwrap();

    // start with zero counts for all types
    let mut counts = RecordTag::iter()
        .map(|r| (r, 0_u64))
        .collect::<collections::HashMap<RecordTag, u64>>();

    // overwrite zeros with real counts for each record that exists in the hprof
    hprof
        .records_iter()
        .map(|r| r.unwrap().tag())
        .for_each(|tag| {
            counts.entry(tag).and_modify(|c| *c += 1).or_insert(1);
        });

    let mut counts: Vec<(RecordTag, u64)> = counts
        .into_iter()
        .collect::<Vec<(jvm_hprof::RecordTag, u64)>>();

    // highest count on top
    counts.sort_unstable_by_key(|&(_, count)| count);
    counts.reverse();

    for (tag, count) in counts {
        println!("{:?}: {}", tag, count);
    }
}

Modules

heap_dump

Sub records contained in crate::HeapDumpSegment records.

Structs

Header

Basic metadata about the hprof

HeapDumpSegment

Contents of a Record with tag RecordTag::HeapDump or RecordTag::HeapDumpSegment.

Hprof

The top level of data loaded from an .hprof file.

Id

Ids are used to identify many things in an hprof file: objects, classes, utf8 blobs, etc.

Ids

Iterator that parses ids.

LoadClass

Contents of a Record with tag RecordTag::LoadClass.

Record

The next level down from the Hprof in the hierarchy of data.

RecordTagIter

Records

Iterator over the Record data in an hprof.

Serial

An alternate means of identification used in parallel with Id.

StackFrame

Contents of a Record with tag RecordTag::StackFrame.

StackTrace

Contents of a Record with tag RecordTag::StackTrace.

SubRecords

Iterator over heap_dump::SubRecord data.

Utf8

Contents of a Record with tag RecordTag::Utf8.

Enums

IdSize

Hprof ids can be 32 or 64 bit, depending on the system and JVM that the hprof was captured on.

LineNum

A line referenced from a stack frame.

RecordTag

Indicates what type of data is contained in a particular Record.

Traits

EnumIterable

Allow iterating over enum variants for enums that have #[derive(EnumIter)].

Functions

parse_hprof

Entry point for parsing.