Conditional import deps for `arrow-deps` sub-crate

[apache]

Conditional import deps for `arrow-deps` sub-crate

[messense]

@waynexia #108

[messense]

Since ceresdb-client-py only needs the Datum type, what do you think about the following change? Just feature-gate arrow-deps for now.

diff --git a/common_types/Cargo.toml b/common_types/Cargo.toml
index ed2736d..59558f6 100644
--- a/common_types/Cargo.toml
+++ b/common_types/Cargo.toml
@@ -7,11 +7,12 @@ edition = "2018"
 # See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
 
 [features]
+default = ["arrow_deps"]
 test = []
 
 [dependencies]
 # In alphabetical order
-arrow_deps = { path = "../arrow_deps" }
+arrow_deps = { path = "../arrow_deps", optional = true }
 byteorder = "1.2"
 bytes = { path = "../components/bytes" }
 chrono = "0.4"
diff --git a/common_types/src/datum.rs b/common_types/src/datum.rs
index 4e9dc03..84ff4e4 100644
--- a/common_types/src/datum.rs
+++ b/common_types/src/datum.rs
@@ -4,6 +4,7 @@
 
 use std::{convert::TryFrom, fmt, str};
 
+#[cfg(feature = "arrow_deps")]
 use arrow_deps::{
     arrow::datatypes::{DataType, TimeUnit},
     datafusion::scalar::ScalarValue,
@@ -156,6 +157,7 @@ impl DatumKind {
 
     /// Create DatumKind from [arrow_deps::arrow::datatypes::DataType], if the
     /// type is not supported, returns None
+    #[cfg(feature = "arrow_deps")]
     pub fn from_data_type(data_type: &DataType) -> Option<Self> {
         match data_type {
             DataType::Null => Some(Self::Null),
@@ -223,6 +225,7 @@ impl DatumKind {
     }
 }
 
+#[cfg(feature = "arrow_deps")]
 impl From<DatumKind> for DataType {
     fn from(kind: DatumKind) -> Self {
         match kind {
@@ -609,6 +612,7 @@ impl Datum {
         }
     }
 
+    #[cfg(feature = "arrow_deps")]
     pub fn as_scalar_value(&self) -> Option<ScalarValue> {
         match self {
             Datum::Null => None,
@@ -787,6 +791,7 @@ impl<'a> DatumView<'a> {
         }
     }
 
+    #[cfg(feature = "arrow_deps")]
     pub fn from_scalar_value(val: &'a ScalarValue) -> Option<Self> {
         match val {
             ScalarValue::Boolean(v) => v.map(DatumView::Boolean),
diff --git a/common_types/src/lib.rs b/common_types/src/lib.rs
index e247e2f..a07ca1c 100644
--- a/common_types/src/lib.rs
+++ b/common_types/src/lib.rs
@@ -3,14 +3,20 @@
 //! Contains common types
 
 pub mod bytes;
+#[cfg(feature = "arrow_deps")]
 pub mod column;
+#[cfg(feature = "arrow_deps")]
 pub mod column_schema;
 pub mod datum;
 pub mod hash;
+#[cfg(feature = "arrow_deps")]
 pub mod projected_schema;
+#[cfg(feature = "arrow_deps")]
 pub mod record_batch;
 pub mod request_id;
+#[cfg(feature = "arrow_deps")]
 pub mod row;
+#[cfg(feature = "arrow_deps")]
 pub mod schema;
 pub mod string;
 pub mod time;

[waynexia]

Since ceresdb-client-py only needs the Datum type, what do you think about the following change? Just feature-gate arrow-deps for now.

This looks pretty neat to me 👍 would you like to submit this patch?