Flag options for different stat categories

.vscode/launch.json

@@ -6,7 +6,7 @@
             "type": "gdb",
             "request": "launch",
             "target": "./target/debug/zi",
-            "arguments": "--help",
+            "arguments": "test.zip",
             "cwd": "${workspaceRoot}"
         }
     ]

src/flat_writer.rs

@@ -1,7 +1,9 @@
 use ::glob;
 use ::zip;
 use std::fs;
+
 use zip_info::WriteZipInfo;
+use zip_info::StatArgs;
 
 /// Info Writer for multiple archive files:
 pub struct MultiArchiveFlatWriter<'a> {
@@ -17,12 +19,12 @@ impl<'a> MultiArchiveFlatWriter<'a> {
 impl<'a> WriteZipInfo for MultiArchiveFlatWriter<'a> {
     /// Given path names for multiple archives, concatenate their
     /// names, contents, and stats:
-    fn write_zip_info(&mut self, exclude: &str) -> String {
+    fn write_zip_info(&mut self, exclude: &str, stat_args: &StatArgs) -> String {
         let mut output = Vec::new();
 
         for path_name in self.path_names {
             let archive_info = ZipInfoFlatWriter::new(path_name.as_str())
-                .write_zip_info(exclude);
+                .write_zip_info(exclude, stat_args);
 
             output.push(archive_info);
         }
@@ -49,7 +51,7 @@ impl<'a> ZipInfoFlatWriter<'a> {
 
 impl<'a> WriteZipInfo for ZipInfoFlatWriter<'a> {
     /// Concatenate Zip file name with indented stats for an archive:
-    fn write_zip_info(&mut self, exclude: &str) -> String {
+    fn write_zip_info(&mut self, exclude: &str, stat_args: &StatArgs) -> String {
         let mut info = format!("{}", self.path_name);
 
         let exclude_pattern = glob::Pattern::new(exclude).unwrap();
@@ -58,29 +60,36 @@ impl<'a> WriteZipInfo for ZipInfoFlatWriter<'a> {
             let archive_item = self.archive.by_index(i).unwrap();
 
             if !exclude_pattern.matches(archive_item.name()) {
-                info = format!("{}{}", info, info_for_archive_item(archive_item));
+                info = format!("{}{}", info, info_for_archive_item(archive_item, stat_args));
             }
         }
 
         info
     }
 }
 
-fn info_for_archive_item(archive_item: zip::read::ZipFile) -> String {
+fn info_for_archive_item(archive_item: zip::read::ZipFile, stat_args: &StatArgs) -> String {
     let mut info = String::new();
     let item_path = archive_item.name();
     info = format!("{}\n\t{}", info, item_path);
 
-    let compression_type = archive_item.compression();
-    info = format!("{}\n\t\tCompression type: {}", info, compression_type);
+    if stat_args.flag_compression_type {
+        let compression_type = archive_item.compression();
+        info = format!("{}\n\t\tCompression type: {}", info, compression_type);
+    }
 
+    // Can't think of a way to avoid evaluating original_size or compressed_size without dependent typing...
     let original_size = archive_item.size();
-    info = format!("{}\n\t\tOriginal size: {}", info, original_size);
+    if stat_args.flag_original_size {
+        info = format!("{}\n\t\tOriginal size: {}", info, original_size);
+    }
 
     let compressed_size = archive_item.compressed_size();
-    info = format!("{}\n\t\tCompressed size: {}", info, compressed_size);
+    if stat_args.flag_compressed_size {
+        info = format!("{}\n\t\tCompressed size: {}", info, compressed_size);
+    }
 
-    if original_size > 0 {
+    if stat_args.flag_compression_rate && original_size > 0 {
         let compression_rate =
             (original_size as f64 - compressed_size as f64)
             / original_size as f64;

src/json_writer.rs

@@ -4,14 +4,20 @@ use ::zip;
 use std::collections::HashMap;
 use std::fs;
 
-pub fn zips_to_json(file_paths: &[&str], exclude: &str) -> String {
-    let multi_archive = MultiArchiveJsonWriter::from(file_paths, exclude);
-    serde_json::to_string(&multi_archive).unwrap()
+use zip_info::StatArgs;
+
+pub fn zips_to_json(file_paths: &[&str], exclude: &str, stat_args: &StatArgs) -> String {
+    zips_to_json_with_printer(file_paths, exclude, stat_args, serde_json::to_string)
+}
+
+pub fn zips_to_json_pretty(file_paths: &[&str], exclude: &str, stat_args: &StatArgs) -> String {
+    zips_to_json_with_printer(file_paths, exclude, stat_args, serde_json::to_string_pretty)
 }
 
-pub fn zips_to_json_pretty(file_paths: &[&str], exclude: &str) -> String {
-    let multi_archive = MultiArchiveJsonWriter::from(file_paths,exclude);
-    serde_json::to_string_pretty(&multi_archive).unwrap()
+fn zips_to_json_with_printer<F>(file_paths: &[&str], exclude: &str, stat_args: &StatArgs, printer: F) -> String 
+    where F: Fn(&MultiArchiveJsonWriter) -> serde_json::Result<String> {
+    let multi_archive = MultiArchiveJsonWriter::from(file_paths, exclude, stat_args);
+    printer(&multi_archive).unwrap()
 }
 
 #[derive(Serialize, Deserialize, Debug, PartialEq)]
@@ -28,13 +34,13 @@ impl MultiArchiveJsonWriter {
     /// Create and fill MultiArchiveJsonWriter representing
     /// zero to many .zip files:
     pub fn from(
-        file_paths: &[&str], exclude: &str) -> MultiArchiveJsonWriter {
+        file_paths: &[&str], exclude: &str, stat_args: &StatArgs) -> MultiArchiveJsonWriter {
         let mut multi_archive = MultiArchiveJsonWriter::new();
 
         for path in file_paths {
             multi_archive.archives.insert(
                 String::from(*path),
-                ZipArchiveJsonWriter::from(*path, exclude),
+                ZipArchiveJsonWriter::from(*path, exclude, stat_args),
             );
         }
 
@@ -55,7 +61,7 @@ impl ZipArchiveJsonWriter {
 
     /// Create and fill ZipArchiveJsonWriter representing a
     /// .zip file:
-    pub fn from(file_path: &str, exclude: &str) -> ZipArchiveJsonWriter {
+    pub fn from(file_path: &str, exclude: &str, stat_args: &StatArgs) -> ZipArchiveJsonWriter {
         let mut archive_writer = ZipArchiveJsonWriter::new();
         let exclude_pattern = glob::Pattern::new(exclude).unwrap();
 
@@ -71,10 +77,15 @@ impl ZipArchiveJsonWriter {
             if !exclude_pattern.matches(zip_object.name()) {
                 archive_writer.objects.insert(
                     String::from(zip_object.name()),
+                    // I wanted to prevent the evaluation of as many of these parameters at this level as possible
+                    // but it seems that because compression rate depends on both .size() and .compressed_size(), we
+                    // need both to be passed in to calculate compression_rate if needed. (No way to encode this 
+                    // dependency here without dependent types.)
                     ZipObjectJsonWriter::new(
-                        zip_object.compression(),
+                        if stat_args.flag_compression_type { Some(zip_object.compression()) } else { None },
                         zip_object.size(),
                         zip_object.compressed_size(),
+                        stat_args,
                     ),
                 );
             }
@@ -84,33 +95,51 @@ impl ZipArchiveJsonWriter {
     }
 }
 
+// We are going to use Option types here to denote that not
+// all of these are going to be calculated, based on certain
+// command-line flags given to this program.
+//
+// TODO: Figure out how to get the JSON serializer to dump fields
+// that are set to null, if this is something that we want in the
+// feature.
 #[derive(Serialize, Deserialize, Debug, PartialEq)]
 struct ZipObjectJsonWriter {
-    compression_type: String,
-    original_size: u64,
-    compressed_size: u64,
-    compression_rate: String,
+    #[serde(skip_serializing_if="Option::is_none")]
+    compression_type: Option<String>,
+    #[serde(skip_serializing_if="Option::is_none")]
+    original_size: Option<u64>,
+    #[serde(skip_serializing_if="Option::is_none")]
+    compressed_size: Option<u64>,
+    #[serde(skip_serializing_if="Option::is_none")]
+    compression_rate: Option<String>,
 }
 
 impl ZipObjectJsonWriter {
     pub fn new(
-        compression_type: zip::CompressionMethod,
+        compression_type: Option<zip::CompressionMethod>,
         original_size: u64,
         compressed_size: u64,
+        stat_args: &StatArgs,
     ) -> ZipObjectJsonWriter {
-        let compression_rate = match original_size {
-            0 => 0.0 as f64,
-            _ => {
-                (original_size as f64 - compressed_size as f64)
-                / original_size as f64
-            },
-        };
+        let compression_rate =
+            if stat_args.flag_compression_rate {
+                Some(match original_size {
+                    0 => 0.0 as f64,
+                    _ => {
+                        (original_size as f64 - compressed_size as f64)
+                        / original_size as f64
+                    },
+                })
+            }
+            else {
+                None
+            };
 
         ZipObjectJsonWriter {
-            compression_type: format!("{}", compression_type),
-            original_size: original_size,
-            compressed_size: compressed_size,
-            compression_rate: format!("{:.*}%", 2, compression_rate * 100.0),
+            compression_type: compression_type.and_then(|v| Some(format!("{}", v))),
+            original_size: if stat_args.flag_original_size { Some(original_size) } else { None },
+            compressed_size: if stat_args.flag_compressed_size { Some(compressed_size) } else { None },
+            compression_rate: compression_rate.and_then(|v| Some(format!("{:.*}%", 2, v * 100.0))),
         }
     }
 }
@@ -121,10 +150,10 @@ mod tests {
 
     fn get_zip_object() -> ZipObjectJsonWriter {
         ZipObjectJsonWriter {
-            compression_type: format!("{}", zip::CompressionMethod::Deflated),
-            original_size: 100,
-            compressed_size: 50,
-            compression_rate: String::from("50%"),
+            compression_type: Some(format!("{}", zip::CompressionMethod::Deflated)),
+            original_size: Some(100),
+            compressed_size: Some(50),
+            compression_rate: Some(String::from("50%")),
         }
     }
 
@@ -137,28 +166,31 @@ mod tests {
     #[test]
     fn test_new_zip_object_calculates_percentages() {
         let zip_object = ZipObjectJsonWriter::new(
-            zip::CompressionMethod::Deflated,
+            Some(zip::CompressionMethod::Deflated),
             100,
             50,
+            &StatArgs::default(),
         );
 
-        assert_eq!("50.00%", zip_object.compression_rate);
+        assert_eq!("50.00%", zip_object.compression_rate.unwrap_or_default());
 
         let zip_object_empty = ZipObjectJsonWriter::new(
-            zip::CompressionMethod::Stored,
+            Some(zip::CompressionMethod::Stored),
             0,
             0,
+            &StatArgs::default(),
         );
 
-        assert_eq!("0.00%", zip_object_empty.compression_rate);
+        assert_eq!("0.00%", zip_object_empty.compression_rate.unwrap_or_default());
 
         let zip_object_grew = ZipObjectJsonWriter::new(
-            zip::CompressionMethod::Deflated,
+            Some(zip::CompressionMethod::Deflated),
             100,
             150,
+            &StatArgs::default(),
         );
 
-        assert_eq!("-50.00%", zip_object_grew.compression_rate);
+        assert_eq!("-50.00%", zip_object_grew.compression_rate.unwrap_or_default());
     }
 
     #[test]

src/main.rs

@@ -15,10 +15,12 @@ mod flat_writer;
 mod json_writer;
 
 use zip_info::WriteZipInfo;
+use zip_info::Args;
+use zip_info::StatArgs;
 
 /// The Docopt usage string
 const USAGE: &'static str = "
-Usage: zi [-j | -p] [--exclude=<glob>] <path> ...
+Usage: zi [-j | -p] [--exclude=<glob>] [options] <path> ...
        zi --help
 
 zi presents information about Zip archives.
@@ -29,21 +31,20 @@ Common options:
     -p, --pretty-json  Structure the output in easy-to-read JSON
     --exclude=<glob>   Ignore objects in the archives whose name
                        is like this glob pattern.
+More options:
+    --compression-type  Show the compression type of each file.
+    --original-size     Show the original size of each file.
+    --compressed-size   Show the compressed size of each file.
+    --compression-rate  Show the compression rate of each file.
 ";
 
-#[derive(Debug, RustcDecodable)]
-struct Args {
-    arg_path: Vec<String>,
-    flag_json: bool,
-    flag_pretty_json: bool,
-    flag_exclude: String,
-}
-
 fn main() {
     let args: Args = Docopt::new(USAGE)
                             .and_then(|d| d.decode())
                             .unwrap_or_else(|e| e.exit());
 
+    let stat_args = StatArgs::new(&args);
+
     // XXX We divide up the display functionality here since
     // the original flat writer works differently than the JSON
     // writer. Ultimately, the JSON writer should be a generic
@@ -54,7 +55,7 @@ fn main() {
             args.arg_path.as_slice()
         );
 
-        println!("{}", multiwriter.write_zip_info(args.flag_exclude.as_str()));
+        println!("{}", multiwriter.write_zip_info(args.flag_exclude.as_str(), &stat_args));
     } else {
         // Convert String to &str for json printing since
         // Docopt appears not to be able to handle Vec<&str>:
@@ -69,6 +70,6 @@ fn main() {
             _ => json_writer::zips_to_json_pretty,
         };
 
-        println!("{}", s(path_names.as_slice(), args.flag_exclude.as_str()));
+        println!("{}", s(path_names.as_slice(), args.flag_exclude.as_str(), &stat_args));
     }
 }

src/zip_info.rs

@@ -1,5 +1,59 @@
 pub trait WriteZipInfo {
-    fn write_zip_info(&mut self, exclude: &str) -> String;
+    fn write_zip_info(&mut self, exclude: &str, stat_args: &StatArgs) -> String;
+}
+
+// Struct for our command-line arguments
+#[derive(Debug, RustcDecodable)]
+pub struct Args {
+    pub arg_path: Vec<String>,
+    pub flag_json: bool,
+    pub flag_pretty_json: bool,
+    pub flag_exclude: String,
+    pub flag_compression_type: bool,
+    pub flag_original_size: bool,
+    pub flag_compressed_size: bool,
+    pub flag_compression_rate: bool,
+}
+
+// We will need to pass this down in the main thread, to the individual printers,
+// and there is no point in passing down the whole Args struct, in the spirit of encapsulation.
+#[derive(Debug)]
+pub struct StatArgs {
+    pub flag_compression_type: bool,
+    pub flag_original_size: bool,
+    pub flag_compressed_size: bool,
+    pub flag_compression_rate: bool,
+}
+
+impl StatArgs {
+    pub fn new(args: &Args) -> StatArgs {
+        let mut stat_args = StatArgs {
+            flag_compression_type: args.flag_compression_type,
+            flag_original_size: args.flag_original_size,
+            flag_compressed_size: args.flag_compressed_size,
+            flag_compression_rate: args.flag_compression_rate,
+        };
+
+        // If none of these are explicitly specified, we print all of them.
+        if stat_args.is_all_false() {
+            stat_args = StatArgs::default();
+        }
+
+        stat_args
+    }
+
+    pub fn default() -> StatArgs {
+        StatArgs {
+            flag_compression_type: true,
+            flag_original_size: true,
+            flag_compressed_size: true,
+            flag_compression_rate: true,
+        }
+    }
+
+    fn is_all_false(&self) -> bool {
+        !(self.flag_compression_type || self.flag_original_size || self.flag_compressed_size || self.flag_compression_rate)
+    }
 }
 
 #[cfg(test)]