Add env_logger to binaries (#66)

This adds logging to inferno-collapse-perf and inferno-flamegraph. 
The following flags were added:
-v increases verbosity
-q silences all logs

Cargo.toml

@@ -27,6 +27,7 @@ object = "0.11"
 gimli = "0.16"
 memmap = "0.7"
 log = "0.4"
+env_logger = "0.6.0"
 quick-xml = "0.13.3"
 num-format = { version = "0.4", default-features = false }
 str_stack = "0.1"

src/bin/collapse-perf.rs

@@ -1,3 +1,4 @@
+use env_logger::Env;
 use std::io;
 use std::path::PathBuf;
 use structopt::StructOpt;
@@ -53,6 +54,14 @@ struct Opt {
     #[structopt(long = "event-filter", value_name = "EVENT")]
     event_filter: Option<String>,
 
+    /// Silence all log output
+    #[structopt(short = "q", long = "quiet")]
+    quiet: bool,
+
+    /// Verbose logging mode (-v, -vv, -vvv)
+    #[structopt(short = "v", long = "verbose", parse(from_occurrences))]
+    verbose: usize,
+
     /// perf script output file, or STDIN if not specified
     infile: Option<PathBuf>,
 }
@@ -76,6 +85,20 @@ impl Opt {
 }
 
 fn main() -> io::Result<()> {
-    let (infile, options) = Opt::from_args().into_parts();
+    let opt = Opt::from_args();
+
+    // Initialize logger
+    if !opt.quiet {
+        env_logger::Builder::from_env(Env::default().default_filter_or(match opt.verbose {
+            0 => "warn",
+            1 => "info",
+            2 => "debug",
+            _ => "trace",
+        }))
+        .default_format_timestamp(false)
+        .init();
+    }
+
+    let (infile, options) = opt.into_parts();
     Folder::from(options).collapse_file(infile.as_ref())
 }

src/bin/flamegraph.rs

@@ -1,3 +1,4 @@
+use env_logger::Env;
 use std::fs::File;
 use std::io::{self, BufReader, Read};
 use std::path::PathBuf;
@@ -48,6 +49,14 @@ struct Opt {
     /// Factor to scale sample counts by
     #[structopt(long = "factor", default_value = "1.0")]
     factor: f64,
+
+    /// Silence all log output
+    #[structopt(short = "q", long = "quiet")]
+    quiet: bool,
+
+    /// Verbose logging mode (-v, -vv, -vvv)
+    #[structopt(short = "v", long = "verbose", parse(from_occurrences))]
+    verbose: usize,
 }
 
 impl Into<Options> for Opt {
@@ -78,6 +87,18 @@ impl Into<Options> for Opt {
 fn main() -> quick_xml::Result<()> {
     let opt = Opt::from_args();
 
+    // Initialize logger
+    if !opt.quiet {
+        env_logger::Builder::from_env(Env::default().default_filter_or(match opt.verbose {
+            0 => "warn",
+            1 => "info",
+            2 => "debug",
+            _ => "trace",
+        }))
+        .default_format_timestamp(false)
+        .init();
+    }
+
     if opt.infiles.is_empty() || opt.infiles.len() == 1 && opt.infiles[0].to_str() == Some("-") {
         let stdin = io::stdin();
         let r = BufReader::with_capacity(128 * 1024, stdin.lock());