Multirust-compatible racer wrapper with OS X support

README.md

This wrapper automatically sets the RUST_SRC_DIRECTORY environment variable for whatever rust compiler is currently active, automatically creating a new checkout whenever necessary. This should be compatible with all of the multirust-alike tools, but it has only been tested with rustup.rs

Installation

Simply place this somewhere on your path before the main racer binary and set the execute bit.

Uninstallation

See rm(1).

Bugs

If you keep up to date with nightly, this will likely result in your disk slowly filling with copies of the rust source tree. While there are far worse uses for the disk space, you also likely have better. You may simply delete all directories beginning with rust- in $RUST_SOURCE_ROOT (${RUSTUP_HOME}/src or ${HOME}/.multirust/src, whichever is defined) to reclaim the disk space. (Strictly speaking, you can also remove the git directory, but it will automatically be redownloaded the next time the wrapper is run so this usually doens't make sense.)

Changes

1. OSX support
2. Pass correct CARGO_HOME variable to racer

racer

#!/bin/bash

# Set a default for RUSTUP_HOME
: ${RUSTUP_HOME:=${HOME}/.multirust}
: ${RUST_SOURCE_ROOT:=${RUSTUP_HOME}/src}

[[ -d ${RUST_SOURCE_ROOT} ]] || mkdir -p "${RUST_SOURCE_ROOT}"

SELF_FOUND=0
# TODO: This doesn't deal well with path entries that contain spaces
for cmd in $(which -a "$(basename "$0")"); do
    if (( $SELF_FOUND == 1 )); then
        NEXT_RACER="${cmd}"
    elif [[ "${cmd}" -ef "$0" ]]; then
        SELF_FOUND=1
    fi
done
if ! (( $SELF_FOUND )); then
   : ${NEXT_RACER:=racer}
fi

function last_modified() {
    FILE=$1
    MODIFIED=0
    if [[ "$OSTYPE" == "linux-gnu" ]]; then
        MODIFIED=$(stat -c %Y "${FILE}")
    elif [[ "$OSTYPE" == darwin* ]]; then
        MODIFIED=$(stat -f %m "${FILE}")
    else
        # TODO: check BSD
        # `man stat` on OS X says:
        # > The stat utility appeared in NetBSD 1.6 and FreeBSD 4.10.
        # so I assume it's safe to use same parameters as OSX
        MODIFIED=$(stat -f %m "${FILE}")
    fi
    echo $MODIFIED
}

function vivify() {
    HASH=$1
    
    export GIT_DIR="$RUSTUP_HOME/src/git"
    if ! [[ -d "${GIT_DIR}" ]]; then
        git clone --bare --quiet https://github.com/rust-lang/rust "${GIT_DIR}"
    fi
    
    if (( $(date +%s) - 3600*12 > $(last_modified "${GIT_DIR}") )); then
        git fetch --all
    fi
    
    TREE="$(git rev-parse --verify --quiet "${HASH}^{tree}")"
    if [[ $? -ne 0 ]]; then
        echo "Inable to resolve ${HASH}" >/dev/stderr
        exit 1
    fi
    
    if ! [[ -d "${RUST_SOURCE_ROOT}/rust-${TREE}" ]]; then
        git archive --prefix=rust-"${TREE}/" ${HASH} | tar xC "${RUST_SOURCE_ROOT}"
    fi
    echo "${RUST_SOURCE_ROOT}/rust-${TREE}"
}

function rust_version() {
    # Get the current rust compiler version
    local RUST_COMMIT="$(rustc -vV 2>/dev/null |awk '($1 == "commit-hash:") { print $2 }')"
    if (( $? )); then
        echo "Rust isn't installed!" >/dev/stderr
        exit 2
    fi
    echo $RUST_COMMIT
}

exec env RUST_SRC_PATH="$(vivify "$(rust_version)")/src" CARGO_HOME="$HOME/.cargo/" "${NEXT_RACER}" "$@"