| use std::{fs::File, io, path::Path, result}; |
| |
| use { |
| csv_core::{ |
| self, WriteResult, Writer as CoreWriter, |
| WriterBuilder as CoreWriterBuilder, |
| }, |
| serde::Serialize, |
| }; |
| |
| use crate::{ |
| byte_record::ByteRecord, |
| error::{Error, ErrorKind, IntoInnerError, Result}, |
| serializer::{serialize, serialize_header}, |
| {QuoteStyle, Terminator}, |
| }; |
| |
| /// Builds a CSV writer with various configuration knobs. |
| /// |
| /// This builder can be used to tweak the field delimiter, record terminator |
| /// and more. Once a CSV `Writer` is built, its configuration cannot be |
| /// changed. |
| #[derive(Debug)] |
| pub struct WriterBuilder { |
| builder: CoreWriterBuilder, |
| capacity: usize, |
| flexible: bool, |
| has_headers: bool, |
| } |
| |
| impl Default for WriterBuilder { |
| fn default() -> WriterBuilder { |
| WriterBuilder { |
| builder: CoreWriterBuilder::default(), |
| capacity: 8 * (1 << 10), |
| flexible: false, |
| has_headers: true, |
| } |
| } |
| } |
| |
| impl WriterBuilder { |
| /// Create a new builder for configuring CSV writing. |
| /// |
| /// To convert a builder into a writer, call one of the methods starting |
| /// with `from_`. |
| /// |
| /// # Example |
| /// |
| /// ``` |
| /// use std::error::Error; |
| /// use csv::WriterBuilder; |
| /// |
| /// # fn main() { example().unwrap(); } |
| /// fn example() -> Result<(), Box<dyn Error>> { |
| /// let mut wtr = WriterBuilder::new().from_writer(vec![]); |
| /// wtr.write_record(&["a", "b", "c"])?; |
| /// wtr.write_record(&["x", "y", "z"])?; |
| /// |
| /// let data = String::from_utf8(wtr.into_inner()?)?; |
| /// assert_eq!(data, "a,b,c\nx,y,z\n"); |
| /// Ok(()) |
| /// } |
| /// ``` |
| pub fn new() -> WriterBuilder { |
| WriterBuilder::default() |
| } |
| |
| /// Build a CSV writer from this configuration that writes data to the |
| /// given file path. The file is truncated if it already exists. |
| /// |
| /// If there was a problem opening the file at the given path, then this |
| /// returns the corresponding error. |
| /// |
| /// # Example |
| /// |
| /// ```no_run |
| /// use std::error::Error; |
| /// use csv::WriterBuilder; |
| /// |
| /// # fn main() { example().unwrap(); } |
| /// fn example() -> Result<(), Box<dyn Error>> { |
| /// let mut wtr = WriterBuilder::new().from_path("foo.csv")?; |
| /// wtr.write_record(&["a", "b", "c"])?; |
| /// wtr.write_record(&["x", "y", "z"])?; |
| /// wtr.flush()?; |
| /// Ok(()) |
| /// } |
| /// ``` |
| pub fn from_path<P: AsRef<Path>>(&self, path: P) -> Result<Writer<File>> { |
| Ok(Writer::new(self, File::create(path)?)) |
| } |
| |
| /// Build a CSV writer from this configuration that writes data to `wtr`. |
| /// |
| /// Note that the CSV writer is buffered automatically, so you should not |
| /// wrap `wtr` in a buffered writer like `io::BufWriter`. |
| /// |
| /// # Example |
| /// |
| /// ``` |
| /// use std::error::Error; |
| /// use csv::WriterBuilder; |
| /// |
| /// # fn main() { example().unwrap(); } |
| /// fn example() -> Result<(), Box<dyn Error>> { |
| /// let mut wtr = WriterBuilder::new().from_writer(vec![]); |
| /// wtr.write_record(&["a", "b", "c"])?; |
| /// wtr.write_record(&["x", "y", "z"])?; |
| /// |
| /// let data = String::from_utf8(wtr.into_inner()?)?; |
| /// assert_eq!(data, "a,b,c\nx,y,z\n"); |
| /// Ok(()) |
| /// } |
| /// ``` |
| pub fn from_writer<W: io::Write>(&self, wtr: W) -> Writer<W> { |
| Writer::new(self, wtr) |
| } |
| |
| /// The field delimiter to use when writing CSV. |
| /// |
| /// The default is `b','`. |
| /// |
| /// # Example |
| /// |
| /// ``` |
| /// use std::error::Error; |
| /// use csv::WriterBuilder; |
| /// |
| /// # fn main() { example().unwrap(); } |
| /// fn example() -> Result<(), Box<dyn Error>> { |
| /// let mut wtr = WriterBuilder::new() |
| /// .delimiter(b';') |
| /// .from_writer(vec![]); |
| /// wtr.write_record(&["a", "b", "c"])?; |
| /// wtr.write_record(&["x", "y", "z"])?; |
| /// |
| /// let data = String::from_utf8(wtr.into_inner()?)?; |
| /// assert_eq!(data, "a;b;c\nx;y;z\n"); |
| /// Ok(()) |
| /// } |
| /// ``` |
| pub fn delimiter(&mut self, delimiter: u8) -> &mut WriterBuilder { |
| self.builder.delimiter(delimiter); |
| self |
| } |
| |
| /// Whether to write a header row before writing any other row. |
| /// |
| /// When this is enabled and the `serialize` method is used to write data |
| /// with something that contains field names (i.e., a struct), then a |
| /// header row is written containing the field names before any other row |
| /// is written. |
| /// |
| /// This option has no effect when using other methods to write rows. That |
| /// is, if you don't use `serialize`, then you must write your header row |
| /// explicitly if you want a header row. |
| /// |
| /// This is enabled by default. |
| /// |
| /// # Example: with headers |
| /// |
| /// This shows how the header will be automatically written from the field |
| /// names of a struct. |
| /// |
| /// ``` |
| /// use std::error::Error; |
| /// |
| /// use csv::WriterBuilder; |
| /// |
| /// #[derive(serde::Serialize)] |
| /// struct Row<'a> { |
| /// city: &'a str, |
| /// country: &'a str, |
| /// // Serde allows us to name our headers exactly, |
| /// // even if they don't match our struct field names. |
| /// #[serde(rename = "popcount")] |
| /// population: u64, |
| /// } |
| /// |
| /// # fn main() { example().unwrap(); } |
| /// fn example() -> Result<(), Box<dyn Error>> { |
| /// let mut wtr = WriterBuilder::new().from_writer(vec![]); |
| /// wtr.serialize(Row { |
| /// city: "Boston", |
| /// country: "United States", |
| /// population: 4628910, |
| /// })?; |
| /// wtr.serialize(Row { |
| /// city: "Concord", |
| /// country: "United States", |
| /// population: 42695, |
| /// })?; |
| /// |
| /// let data = String::from_utf8(wtr.into_inner()?)?; |
| /// assert_eq!(data, "\ |
| /// city,country,popcount |
| /// Boston,United States,4628910 |
| /// Concord,United States,42695 |
| /// "); |
| /// Ok(()) |
| /// } |
| /// ``` |
| /// |
| /// # Example: without headers |
| /// |
| /// This shows that serializing things that aren't structs (in this case, |
| /// a tuple struct) won't result in a header row being written. This means |
| /// you usually don't need to set `has_headers(false)` unless you |
| /// explicitly want to both write custom headers and serialize structs. |
| /// |
| /// ``` |
| /// use std::error::Error; |
| /// use csv::WriterBuilder; |
| /// |
| /// # fn main() { example().unwrap(); } |
| /// fn example() -> Result<(), Box<dyn Error>> { |
| /// let mut wtr = WriterBuilder::new().from_writer(vec![]); |
| /// wtr.serialize(("Boston", "United States", 4628910))?; |
| /// wtr.serialize(("Concord", "United States", 42695))?; |
| /// |
| /// let data = String::from_utf8(wtr.into_inner()?)?; |
| /// assert_eq!(data, "\ |
| /// Boston,United States,4628910 |
| /// Concord,United States,42695 |
| /// "); |
| /// Ok(()) |
| /// } |
| /// ``` |
| pub fn has_headers(&mut self, yes: bool) -> &mut WriterBuilder { |
| self.has_headers = yes; |
| self |
| } |
| |
| /// Whether the number of fields in records is allowed to change or not. |
| /// |
| /// When disabled (which is the default), writing CSV data will return an |
| /// error if a record is written with a number of fields different from the |
| /// number of fields written in a previous record. |
| /// |
| /// When enabled, this error checking is turned off. |
| /// |
| /// # Example: writing flexible records |
| /// |
| /// ``` |
| /// use std::error::Error; |
| /// use csv::WriterBuilder; |
| /// |
| /// # fn main() { example().unwrap(); } |
| /// fn example() -> Result<(), Box<dyn Error>> { |
| /// let mut wtr = WriterBuilder::new() |
| /// .flexible(true) |
| /// .from_writer(vec![]); |
| /// wtr.write_record(&["a", "b"])?; |
| /// wtr.write_record(&["x", "y", "z"])?; |
| /// |
| /// let data = String::from_utf8(wtr.into_inner()?)?; |
| /// assert_eq!(data, "a,b\nx,y,z\n"); |
| /// Ok(()) |
| /// } |
| /// ``` |
| /// |
| /// # Example: error when `flexible` is disabled |
| /// |
| /// ``` |
| /// use std::error::Error; |
| /// use csv::WriterBuilder; |
| /// |
| /// # fn main() { example().unwrap(); } |
| /// fn example() -> Result<(), Box<dyn Error>> { |
| /// let mut wtr = WriterBuilder::new() |
| /// .flexible(false) |
| /// .from_writer(vec![]); |
| /// wtr.write_record(&["a", "b"])?; |
| /// let err = wtr.write_record(&["x", "y", "z"]).unwrap_err(); |
| /// match *err.kind() { |
| /// csv::ErrorKind::UnequalLengths { expected_len, len, .. } => { |
| /// assert_eq!(expected_len, 2); |
| /// assert_eq!(len, 3); |
| /// } |
| /// ref wrong => { |
| /// panic!("expected UnequalLengths but got {:?}", wrong); |
| /// } |
| /// } |
| /// Ok(()) |
| /// } |
| /// ``` |
| pub fn flexible(&mut self, yes: bool) -> &mut WriterBuilder { |
| self.flexible = yes; |
| self |
| } |
| |
| /// The record terminator to use when writing CSV. |
| /// |
| /// A record terminator can be any single byte. The default is `\n`. |
| /// |
| /// Note that RFC 4180 specifies that record terminators should be `\r\n`. |
| /// To use `\r\n`, use the special `Terminator::CRLF` value. |
| /// |
| /// # Example: CRLF |
| /// |
| /// This shows how to use RFC 4180 compliant record terminators. |
| /// |
| /// ``` |
| /// use std::error::Error; |
| /// use csv::{Terminator, WriterBuilder}; |
| /// |
| /// # fn main() { example().unwrap(); } |
| /// fn example() -> Result<(), Box<dyn Error>> { |
| /// let mut wtr = WriterBuilder::new() |
| /// .terminator(Terminator::CRLF) |
| /// .from_writer(vec![]); |
| /// wtr.write_record(&["a", "b", "c"])?; |
| /// wtr.write_record(&["x", "y", "z"])?; |
| /// |
| /// let data = String::from_utf8(wtr.into_inner()?)?; |
| /// assert_eq!(data, "a,b,c\r\nx,y,z\r\n"); |
| /// Ok(()) |
| /// } |
| /// ``` |
| pub fn terminator(&mut self, term: Terminator) -> &mut WriterBuilder { |
| self.builder.terminator(term.to_core()); |
| self |
| } |
| |
| /// The quoting style to use when writing CSV. |
| /// |
| /// By default, this is set to `QuoteStyle::Necessary`, which will only |
| /// use quotes when they are necessary to preserve the integrity of data. |
| /// |
| /// Note that unless the quote style is set to `Never`, an empty field is |
| /// quoted if it is the only field in a record. |
| /// |
| /// # Example: non-numeric quoting |
| /// |
| /// This shows how to quote non-numeric fields only. |
| /// |
| /// ``` |
| /// use std::error::Error; |
| /// use csv::{QuoteStyle, WriterBuilder}; |
| /// |
| /// # fn main() { example().unwrap(); } |
| /// fn example() -> Result<(), Box<dyn Error>> { |
| /// let mut wtr = WriterBuilder::new() |
| /// .quote_style(QuoteStyle::NonNumeric) |
| /// .from_writer(vec![]); |
| /// wtr.write_record(&["a", "5", "c"])?; |
| /// wtr.write_record(&["3.14", "y", "z"])?; |
| /// |
| /// let data = String::from_utf8(wtr.into_inner()?)?; |
| /// assert_eq!(data, "\"a\",5,\"c\"\n3.14,\"y\",\"z\"\n"); |
| /// Ok(()) |
| /// } |
| /// ``` |
| /// |
| /// # Example: never quote |
| /// |
| /// This shows how the CSV writer can be made to never write quotes, even |
| /// if it sacrifices the integrity of the data. |
| /// |
| /// ``` |
| /// use std::error::Error; |
| /// use csv::{QuoteStyle, WriterBuilder}; |
| /// |
| /// # fn main() { example().unwrap(); } |
| /// fn example() -> Result<(), Box<dyn Error>> { |
| /// let mut wtr = WriterBuilder::new() |
| /// .quote_style(QuoteStyle::Never) |
| /// .from_writer(vec![]); |
| /// wtr.write_record(&["a", "foo\nbar", "c"])?; |
| /// wtr.write_record(&["g\"h\"i", "y", "z"])?; |
| /// |
| /// let data = String::from_utf8(wtr.into_inner()?)?; |
| /// assert_eq!(data, "a,foo\nbar,c\ng\"h\"i,y,z\n"); |
| /// Ok(()) |
| /// } |
| /// ``` |
| pub fn quote_style(&mut self, style: QuoteStyle) -> &mut WriterBuilder { |
| self.builder.quote_style(style.to_core()); |
| self |
| } |
| |
| /// The quote character to use when writing CSV. |
| /// |
| /// The default is `b'"'`. |
| /// |
| /// # Example |
| /// |
| /// ``` |
| /// use std::error::Error; |
| /// use csv::WriterBuilder; |
| /// |
| /// # fn main() { example().unwrap(); } |
| /// fn example() -> Result<(), Box<dyn Error>> { |
| /// let mut wtr = WriterBuilder::new() |
| /// .quote(b'\'') |
| /// .from_writer(vec![]); |
| /// wtr.write_record(&["a", "foo\nbar", "c"])?; |
| /// wtr.write_record(&["g'h'i", "y\"y\"y", "z"])?; |
| /// |
| /// let data = String::from_utf8(wtr.into_inner()?)?; |
| /// assert_eq!(data, "a,'foo\nbar',c\n'g''h''i',y\"y\"y,z\n"); |
| /// Ok(()) |
| /// } |
| /// ``` |
| pub fn quote(&mut self, quote: u8) -> &mut WriterBuilder { |
| self.builder.quote(quote); |
| self |
| } |
| |
| /// Enable double quote escapes. |
| /// |
| /// This is enabled by default, but it may be disabled. When disabled, |
| /// quotes in field data are escaped instead of doubled. |
| /// |
| /// # Example |
| /// |
| /// ``` |
| /// use std::error::Error; |
| /// use csv::WriterBuilder; |
| /// |
| /// # fn main() { example().unwrap(); } |
| /// fn example() -> Result<(), Box<dyn Error>> { |
| /// let mut wtr = WriterBuilder::new() |
| /// .double_quote(false) |
| /// .from_writer(vec![]); |
| /// wtr.write_record(&["a", "foo\"bar", "c"])?; |
| /// wtr.write_record(&["x", "y", "z"])?; |
| /// |
| /// let data = String::from_utf8(wtr.into_inner()?)?; |
| /// assert_eq!(data, "a,\"foo\\\"bar\",c\nx,y,z\n"); |
| /// Ok(()) |
| /// } |
| /// ``` |
| pub fn double_quote(&mut self, yes: bool) -> &mut WriterBuilder { |
| self.builder.double_quote(yes); |
| self |
| } |
| |
| /// The escape character to use when writing CSV. |
| /// |
| /// In some variants of CSV, quotes are escaped using a special escape |
| /// character like `\` (instead of escaping quotes by doubling them). |
| /// |
| /// By default, writing these idiosyncratic escapes is disabled, and is |
| /// only used when `double_quote` is disabled. |
| /// |
| /// # Example |
| /// |
| /// ``` |
| /// use std::error::Error; |
| /// use csv::WriterBuilder; |
| /// |
| /// # fn main() { example().unwrap(); } |
| /// fn example() -> Result<(), Box<dyn Error>> { |
| /// let mut wtr = WriterBuilder::new() |
| /// .double_quote(false) |
| /// .escape(b'$') |
| /// .from_writer(vec![]); |
| /// wtr.write_record(&["a", "foo\"bar", "c"])?; |
| /// wtr.write_record(&["x", "y", "z"])?; |
| /// |
| /// let data = String::from_utf8(wtr.into_inner()?)?; |
| /// assert_eq!(data, "a,\"foo$\"bar\",c\nx,y,z\n"); |
| /// Ok(()) |
| /// } |
| /// ``` |
| pub fn escape(&mut self, escape: u8) -> &mut WriterBuilder { |
| self.builder.escape(escape); |
| self |
| } |
| |
| /// Set the capacity (in bytes) of the internal buffer used in the CSV |
| /// writer. This defaults to a reasonable setting. |
| pub fn buffer_capacity(&mut self, capacity: usize) -> &mut WriterBuilder { |
| self.capacity = capacity; |
| self |
| } |
| } |
| |
| /// An already configured CSV writer. |
| /// |
| /// A CSV writer takes as input Rust values and writes those values in a valid |
| /// CSV format as output. |
| /// |
| /// While CSV writing is considerably easier than parsing CSV, a proper writer |
| /// will do a number of things for you: |
| /// |
| /// 1. Quote fields when necessary. |
| /// 2. Check that all records have the same number of fields. |
| /// 3. Write records with a single empty field correctly. |
| /// 4. Automatically serialize normal Rust types to CSV records. When that |
| /// type is a struct, a header row is automatically written corresponding |
| /// to the fields of that struct. |
| /// 5. Use buffering intelligently and otherwise avoid allocation. (This means |
| /// that callers should not do their own buffering.) |
| /// |
| /// All of the above can be configured using a |
| /// [`WriterBuilder`](struct.WriterBuilder.html). |
| /// However, a `Writer` has a couple of convenience constructors (`from_path` |
| /// and `from_writer`) that use the default configuration. |
| /// |
| /// Note that the default configuration of a `Writer` uses `\n` for record |
| /// terminators instead of `\r\n` as specified by RFC 4180. Use the |
| /// `terminator` method on `WriterBuilder` to set the terminator to `\r\n` if |
| /// it's desired. |
| #[derive(Debug)] |
| pub struct Writer<W: io::Write> { |
| core: CoreWriter, |
| wtr: Option<W>, |
| buf: Buffer, |
| state: WriterState, |
| } |
| |
| #[derive(Debug)] |
| struct WriterState { |
| /// Whether the Serde serializer should attempt to write a header row. |
| header: HeaderState, |
| /// Whether inconsistent record lengths are allowed. |
| flexible: bool, |
| /// The number of fields written in the first record. This is compared |
| /// with `fields_written` on all subsequent records to check for |
| /// inconsistent record lengths. |
| first_field_count: Option<u64>, |
| /// The number of fields written in this record. This is used to report |
| /// errors for inconsistent record lengths if `flexible` is disabled. |
| fields_written: u64, |
| /// This is set immediately before flushing the buffer and then unset |
| /// immediately after flushing the buffer. This avoids flushing the buffer |
| /// twice if the inner writer panics. |
| panicked: bool, |
| } |
| |
| /// HeaderState encodes a small state machine for handling header writes. |
| #[derive(Debug)] |
| enum HeaderState { |
| /// Indicates that we should attempt to write a header. |
| Write, |
| /// Indicates that writing a header was attempted, and a header was written. |
| DidWrite, |
| /// Indicates that writing a header was attempted, but no headers were |
| /// written or the attempt failed. |
| DidNotWrite, |
| /// This state is used when headers are disabled. It cannot transition |
| /// to any other state. |
| None, |
| } |
| |
| /// A simple internal buffer for buffering writes. |
| /// |
| /// We need this because the `csv_core` APIs want to write into a `&mut [u8]`, |
| /// which is not available with the `std::io::BufWriter` API. |
| #[derive(Debug)] |
| struct Buffer { |
| /// The contents of the buffer. |
| buf: Vec<u8>, |
| /// The number of bytes written to the buffer. |
| len: usize, |
| } |
| |
| impl<W: io::Write> Drop for Writer<W> { |
| fn drop(&mut self) { |
| if self.wtr.is_some() && !self.state.panicked { |
| let _ = self.flush(); |
| } |
| } |
| } |
| |
| impl Writer<File> { |
| /// Build a CSV writer with a default configuration that writes data to the |
| /// given file path. The file is truncated if it already exists. |
| /// |
| /// If there was a problem opening the file at the given path, then this |
| /// returns the corresponding error. |
| /// |
| /// # Example |
| /// |
| /// ```no_run |
| /// use std::error::Error; |
| /// use csv::Writer; |
| /// |
| /// # fn main() { example().unwrap(); } |
| /// fn example() -> Result<(), Box<dyn Error>> { |
| /// let mut wtr = Writer::from_path("foo.csv")?; |
| /// wtr.write_record(&["a", "b", "c"])?; |
| /// wtr.write_record(&["x", "y", "z"])?; |
| /// wtr.flush()?; |
| /// Ok(()) |
| /// } |
| /// ``` |
| pub fn from_path<P: AsRef<Path>>(path: P) -> Result<Writer<File>> { |
| WriterBuilder::new().from_path(path) |
| } |
| } |
| |
| impl<W: io::Write> Writer<W> { |
| fn new(builder: &WriterBuilder, wtr: W) -> Writer<W> { |
| let header_state = if builder.has_headers { |
| HeaderState::Write |
| } else { |
| HeaderState::None |
| }; |
| Writer { |
| core: builder.builder.build(), |
| wtr: Some(wtr), |
| buf: Buffer { buf: vec![0; builder.capacity], len: 0 }, |
| state: WriterState { |
| header: header_state, |
| flexible: builder.flexible, |
| first_field_count: None, |
| fields_written: 0, |
| panicked: false, |
| }, |
| } |
| } |
| |
| /// Build a CSV writer with a default configuration that writes data to |
| /// `wtr`. |
| /// |
| /// Note that the CSV writer is buffered automatically, so you should not |
| /// wrap `wtr` in a buffered writer like `io::BufWriter`. |
| /// |
| /// # Example |
| /// |
| /// ``` |
| /// use std::error::Error; |
| /// use csv::Writer; |
| /// |
| /// # fn main() { example().unwrap(); } |
| /// fn example() -> Result<(), Box<dyn Error>> { |
| /// let mut wtr = Writer::from_writer(vec![]); |
| /// wtr.write_record(&["a", "b", "c"])?; |
| /// wtr.write_record(&["x", "y", "z"])?; |
| /// |
| /// let data = String::from_utf8(wtr.into_inner()?)?; |
| /// assert_eq!(data, "a,b,c\nx,y,z\n"); |
| /// Ok(()) |
| /// } |
| /// ``` |
| pub fn from_writer(wtr: W) -> Writer<W> { |
| WriterBuilder::new().from_writer(wtr) |
| } |
| |
| /// Serialize a single record using Serde. |
| /// |
| /// # Example |
| /// |
| /// This shows how to serialize normal Rust structs as CSV records. The |
| /// fields of the struct are used to write a header row automatically. |
| /// (Writing the header row automatically can be disabled by building the |
| /// CSV writer with a [`WriterBuilder`](struct.WriterBuilder.html) and |
| /// calling the `has_headers` method.) |
| /// |
| /// ``` |
| /// use std::error::Error; |
| /// |
| /// use csv::Writer; |
| /// |
| /// #[derive(serde::Serialize)] |
| /// struct Row<'a> { |
| /// city: &'a str, |
| /// country: &'a str, |
| /// // Serde allows us to name our headers exactly, |
| /// // even if they don't match our struct field names. |
| /// #[serde(rename = "popcount")] |
| /// population: u64, |
| /// } |
| /// |
| /// # fn main() { example().unwrap(); } |
| /// fn example() -> Result<(), Box<dyn Error>> { |
| /// let mut wtr = Writer::from_writer(vec![]); |
| /// wtr.serialize(Row { |
| /// city: "Boston", |
| /// country: "United States", |
| /// population: 4628910, |
| /// })?; |
| /// wtr.serialize(Row { |
| /// city: "Concord", |
| /// country: "United States", |
| /// population: 42695, |
| /// })?; |
| /// |
| /// let data = String::from_utf8(wtr.into_inner()?)?; |
| /// assert_eq!(data, "\ |
| /// city,country,popcount |
| /// Boston,United States,4628910 |
| /// Concord,United States,42695 |
| /// "); |
| /// Ok(()) |
| /// } |
| /// ``` |
| /// |
| /// # Rules |
| /// |
| /// The behavior of `serialize` is fairly simple: |
| /// |
| /// 1. Nested containers (tuples, `Vec`s, structs, etc.) are always |
| /// flattened (depth-first order). |
| /// |
| /// 2. If `has_headers` is `true` and the type contains field names, then |
| /// a header row is automatically generated. |
| /// |
| /// However, some container types cannot be serialized, and if |
| /// `has_headers` is `true`, there are some additional restrictions on the |
| /// types that can be serialized. See below for details. |
| /// |
| /// For the purpose of this section, Rust types can be divided into three |
| /// categories: scalars, non-struct containers, and structs. |
| /// |
| /// ## Scalars |
| /// |
| /// Single values with no field names are written like the following. Note |
| /// that some of the outputs may be quoted, according to the selected |
| /// quoting style. |
| /// |
| /// | Name | Example Type | Example Value | Output | |
| /// | ---- | ---- | ---- | ---- | |
| /// | boolean | `bool` | `true` | `true` | |
| /// | integers | `i8`, `i16`, `i32`, `i64`, `i128`, `u8`, `u16`, `u32`, `u64`, `u128` | `5` | `5` | |
| /// | floats | `f32`, `f64` | `3.14` | `3.14` | |
| /// | character | `char` | `'☃'` | `☃` | |
| /// | string | `&str` | `"hi"` | `hi` | |
| /// | bytes | `&[u8]` | `b"hi"[..]` | `hi` | |
| /// | option | `Option` | `None` | *empty* | |
| /// | option | | `Some(5)` | `5` | |
| /// | unit | `()` | `()` | *empty* | |
| /// | unit struct | `struct Foo;` | `Foo` | `Foo` | |
| /// | unit enum variant | `enum E { A, B }` | `E::A` | `A` | |
| /// | newtype struct | `struct Foo(u8);` | `Foo(5)` | `5` | |
| /// | newtype enum variant | `enum E { A(u8) }` | `E::A(5)` | `5` | |
| /// |
| /// Note that this table includes simple structs and enums. For example, to |
| /// serialize a field from either an integer or a float type, one can do |
| /// this: |
| /// |
| /// ``` |
| /// use std::error::Error; |
| /// |
| /// use csv::Writer; |
| /// |
| /// #[derive(serde::Serialize)] |
| /// struct Row { |
| /// label: String, |
| /// value: Value, |
| /// } |
| /// |
| /// #[derive(serde::Serialize)] |
| /// enum Value { |
| /// Integer(i64), |
| /// Float(f64), |
| /// } |
| /// |
| /// # fn main() { example().unwrap(); } |
| /// fn example() -> Result<(), Box<dyn Error>> { |
| /// let mut wtr = Writer::from_writer(vec![]); |
| /// wtr.serialize(Row { |
| /// label: "foo".to_string(), |
| /// value: Value::Integer(3), |
| /// })?; |
| /// wtr.serialize(Row { |
| /// label: "bar".to_string(), |
| /// value: Value::Float(3.14), |
| /// })?; |
| /// |
| /// let data = String::from_utf8(wtr.into_inner()?)?; |
| /// assert_eq!(data, "\ |
| /// label,value |
| /// foo,3 |
| /// bar,3.14 |
| /// "); |
| /// Ok(()) |
| /// } |
| /// ``` |
| /// |
| /// ## Non-Struct Containers |
| /// |
| /// Nested containers are flattened to their scalar components, with the |
| /// exception of a few types that are not allowed: |
| /// |
| /// | Name | Example Type | Example Value | Output | |
| /// | ---- | ---- | ---- | ---- | |
| /// | sequence | `Vec<u8>` | `vec![1, 2, 3]` | `1,2,3` | |
| /// | tuple | `(u8, bool)` | `(5, true)` | `5,true` | |
| /// | tuple struct | `Foo(u8, bool)` | `Foo(5, true)` | `5,true` | |
| /// | tuple enum variant | `enum E { A(u8, bool) }` | `E::A(5, true)` | *error* | |
| /// | struct enum variant | `enum E { V { a: u8, b: bool } }` | `E::V { a: 5, b: true }` | *error* | |
| /// | map | `BTreeMap<K, V>` | `BTreeMap::new()` | *error* | |
| /// |
| /// ## Structs |
| /// |
| /// Like the other containers, structs are flattened to their scalar |
| /// components: |
| /// |
| /// | Name | Example Type | Example Value | Output | |
| /// | ---- | ---- | ---- | ---- | |
| /// | struct | `struct Foo { a: u8, b: bool }` | `Foo { a: 5, b: true }` | `5,true` | |
| /// |
| /// If `has_headers` is `false`, then there are no additional restrictions; |
| /// types can be nested arbitrarily. For example: |
| /// |
| /// ``` |
| /// use std::error::Error; |
| /// |
| /// use csv::WriterBuilder; |
| /// |
| /// #[derive(serde::Serialize)] |
| /// struct Row { |
| /// label: String, |
| /// values: Vec<f64>, |
| /// } |
| /// |
| /// # fn main() { example().unwrap(); } |
| /// fn example() -> Result<(), Box<dyn Error>> { |
| /// let mut wtr = WriterBuilder::new() |
| /// .has_headers(false) |
| /// .from_writer(vec![]); |
| /// wtr.serialize(Row { |
| /// label: "foo".to_string(), |
| /// values: vec![1.1234, 2.5678, 3.14], |
| /// })?; |
| /// |
| /// let data = String::from_utf8(wtr.into_inner()?)?; |
| /// assert_eq!(data, "\ |
| /// foo,1.1234,2.5678,3.14 |
| /// "); |
| /// Ok(()) |
| /// } |
| /// ``` |
| /// |
| /// However, if `has_headers` were enabled in the above example, then |
| /// serialization would return an error. Specifically, when `has_headers` is |
| /// `true`, there are two restrictions: |
| /// |
| /// 1. Named field values in structs must be scalars. |
| /// |
| /// 2. All scalars must be named field values in structs. |
| /// |
| /// Other than these two restrictions, types can be nested arbitrarily. |
| /// Here are a few examples: |
| /// |
| /// | Value | Header | Record | |
| /// | ---- | ---- | ---- | |
| /// | `(Foo { x: 5, y: 6 }, Bar { z: true })` | `x,y,z` | `5,6,true` | |
| /// | `vec![Foo { x: 5, y: 6 }, Foo { x: 7, y: 8 }]` | `x,y,x,y` | `5,6,7,8` | |
| /// | `(Foo { x: 5, y: 6 }, vec![Bar { z: Baz(true) }])` | `x,y,z` | `5,6,true` | |
| /// | `Foo { x: 5, y: (6, 7) }` | *error: restriction 1* | `5,6,7` | |
| /// | `(5, Foo { x: 6, y: 7 }` | *error: restriction 2* | `5,6,7` | |
| /// | `(Foo { x: 5, y: 6 }, true)` | *error: restriction 2* | `5,6,true` | |
| pub fn serialize<S: Serialize>(&mut self, record: S) -> Result<()> { |
| if let HeaderState::Write = self.state.header { |
| let wrote_header = serialize_header(self, &record)?; |
| if wrote_header { |
| self.write_terminator()?; |
| self.state.header = HeaderState::DidWrite; |
| } else { |
| self.state.header = HeaderState::DidNotWrite; |
| }; |
| } |
| serialize(self, &record)?; |
| self.write_terminator()?; |
| Ok(()) |
| } |
| |
| /// Write a single record. |
| /// |
| /// This method accepts something that can be turned into an iterator that |
| /// yields elements that can be represented by a `&[u8]`. |
| /// |
| /// This may be called with an empty iterator, which will cause a record |
| /// terminator to be written. If no fields had been written, then a single |
| /// empty field is written before the terminator. |
| /// |
| /// # Example |
| /// |
| /// ``` |
| /// use std::error::Error; |
| /// use csv::Writer; |
| /// |
| /// # fn main() { example().unwrap(); } |
| /// fn example() -> Result<(), Box<dyn Error>> { |
| /// let mut wtr = Writer::from_writer(vec![]); |
| /// wtr.write_record(&["a", "b", "c"])?; |
| /// wtr.write_record(&["x", "y", "z"])?; |
| /// |
| /// let data = String::from_utf8(wtr.into_inner()?)?; |
| /// assert_eq!(data, "a,b,c\nx,y,z\n"); |
| /// Ok(()) |
| /// } |
| /// ``` |
| pub fn write_record<I, T>(&mut self, record: I) -> Result<()> |
| where |
| I: IntoIterator<Item = T>, |
| T: AsRef<[u8]>, |
| { |
| for field in record.into_iter() { |
| self.write_field_impl(field)?; |
| } |
| self.write_terminator() |
| } |
| |
| /// Write a single `ByteRecord`. |
| /// |
| /// This method accepts a borrowed `ByteRecord` and writes its contents |
| /// to the underlying writer. |
| /// |
| /// This is similar to `write_record` except that it specifically requires |
| /// a `ByteRecord`. This permits the writer to possibly write the record |
| /// more quickly than the more generic `write_record`. |
| /// |
| /// This may be called with an empty record, which will cause a record |
| /// terminator to be written. If no fields had been written, then a single |
| /// empty field is written before the terminator. |
| /// |
| /// # Example |
| /// |
| /// ``` |
| /// use std::error::Error; |
| /// use csv::{ByteRecord, Writer}; |
| /// |
| /// # fn main() { example().unwrap(); } |
| /// fn example() -> Result<(), Box<dyn Error>> { |
| /// let mut wtr = Writer::from_writer(vec![]); |
| /// wtr.write_byte_record(&ByteRecord::from(&["a", "b", "c"][..]))?; |
| /// wtr.write_byte_record(&ByteRecord::from(&["x", "y", "z"][..]))?; |
| /// |
| /// let data = String::from_utf8(wtr.into_inner()?)?; |
| /// assert_eq!(data, "a,b,c\nx,y,z\n"); |
| /// Ok(()) |
| /// } |
| /// ``` |
| #[inline(never)] |
| pub fn write_byte_record(&mut self, record: &ByteRecord) -> Result<()> { |
| if record.as_slice().is_empty() { |
| return self.write_record(record); |
| } |
| // The idea here is to find a fast path for shuffling our record into |
| // our buffer as quickly as possible. We do this because the underlying |
| // "core" CSV writer does a lot of book-keeping to maintain its state |
| // oriented API. |
| // |
| // The fast path occurs when we know our record will fit in whatever |
| // space we have left in our buffer. We can actually quickly compute |
| // the upper bound on the space required: |
| let upper_bound = |
| // The data itself plus the worst case: every byte is a quote. |
| (2 * record.as_slice().len()) |
| // The number of field delimiters. |
| + (record.len().saturating_sub(1)) |
| // The maximum number of quotes inserted around each field. |
| + (2 * record.len()) |
| // The maximum number of bytes for the terminator. |
| + 2; |
| if self.buf.writable().len() < upper_bound { |
| return self.write_record(record); |
| } |
| let mut first = true; |
| for field in record.iter() { |
| if !first { |
| self.buf.writable()[0] = self.core.get_delimiter(); |
| self.buf.written(1); |
| } |
| first = false; |
| |
| if !self.core.should_quote(field) { |
| self.buf.writable()[..field.len()].copy_from_slice(field); |
| self.buf.written(field.len()); |
| } else { |
| self.buf.writable()[0] = self.core.get_quote(); |
| self.buf.written(1); |
| let (res, nin, nout) = csv_core::quote( |
| field, |
| self.buf.writable(), |
| self.core.get_quote(), |
| self.core.get_escape(), |
| self.core.get_double_quote(), |
| ); |
| debug_assert!(res == WriteResult::InputEmpty); |
| debug_assert!(nin == field.len()); |
| self.buf.written(nout); |
| self.buf.writable()[0] = self.core.get_quote(); |
| self.buf.written(1); |
| } |
| } |
| self.state.fields_written = record.len() as u64; |
| self.write_terminator_into_buffer() |
| } |
| |
| /// Write a single field. |
| /// |
| /// One should prefer using `write_record` over this method. It is provided |
| /// for cases where writing a field at a time is more convenient than |
| /// writing a record at a time. |
| /// |
| /// Note that if this API is used, `write_record` should be called with an |
| /// empty iterator to write a record terminator. |
| /// |
| /// # Example |
| /// |
| /// ``` |
| /// use std::error::Error; |
| /// use csv::Writer; |
| /// |
| /// # fn main() { example().unwrap(); } |
| /// fn example() -> Result<(), Box<dyn Error>> { |
| /// let mut wtr = Writer::from_writer(vec![]); |
| /// wtr.write_field("a")?; |
| /// wtr.write_field("b")?; |
| /// wtr.write_field("c")?; |
| /// wtr.write_record(None::<&[u8]>)?; |
| /// wtr.write_field("x")?; |
| /// wtr.write_field("y")?; |
| /// wtr.write_field("z")?; |
| /// wtr.write_record(None::<&[u8]>)?; |
| /// |
| /// let data = String::from_utf8(wtr.into_inner()?)?; |
| /// assert_eq!(data, "a,b,c\nx,y,z\n"); |
| /// Ok(()) |
| /// } |
| /// ``` |
| pub fn write_field<T: AsRef<[u8]>>(&mut self, field: T) -> Result<()> { |
| self.write_field_impl(field) |
| } |
| |
| /// Implementation of write_field. |
| /// |
| /// This is a separate method so we can force the compiler to inline it |
| /// into write_record. |
| #[inline(always)] |
| fn write_field_impl<T: AsRef<[u8]>>(&mut self, field: T) -> Result<()> { |
| if self.state.fields_written > 0 { |
| self.write_delimiter()?; |
| } |
| let mut field = field.as_ref(); |
| loop { |
| let (res, nin, nout) = self.core.field(field, self.buf.writable()); |
| field = &field[nin..]; |
| self.buf.written(nout); |
| match res { |
| WriteResult::InputEmpty => { |
| self.state.fields_written += 1; |
| return Ok(()); |
| } |
| WriteResult::OutputFull => self.flush_buf()?, |
| } |
| } |
| } |
| |
| /// Flush the contents of the internal buffer to the underlying writer. |
| /// |
| /// If there was a problem writing to the underlying writer, then an error |
| /// is returned. |
| /// |
| /// Note that this also flushes the underlying writer. |
| pub fn flush(&mut self) -> io::Result<()> { |
| self.flush_buf()?; |
| self.wtr.as_mut().unwrap().flush()?; |
| Ok(()) |
| } |
| |
| /// Flush the contents of the internal buffer to the underlying writer, |
| /// without flushing the underlying writer. |
| fn flush_buf(&mut self) -> io::Result<()> { |
| self.state.panicked = true; |
| let result = self.wtr.as_mut().unwrap().write_all(self.buf.readable()); |
| self.state.panicked = false; |
| result?; |
| self.buf.clear(); |
| Ok(()) |
| } |
| |
| /// Flush the contents of the internal buffer and return the underlying |
| /// writer. |
| pub fn into_inner( |
| mut self, |
| ) -> result::Result<W, IntoInnerError<Writer<W>>> { |
| match self.flush() { |
| Ok(()) => Ok(self.wtr.take().unwrap()), |
| Err(err) => Err(IntoInnerError::new(self, err)), |
| } |
| } |
| |
| /// Write a CSV delimiter. |
| fn write_delimiter(&mut self) -> Result<()> { |
| loop { |
| let (res, nout) = self.core.delimiter(self.buf.writable()); |
| self.buf.written(nout); |
| match res { |
| WriteResult::InputEmpty => return Ok(()), |
| WriteResult::OutputFull => self.flush_buf()?, |
| } |
| } |
| } |
| |
| /// Write a CSV terminator. |
| fn write_terminator(&mut self) -> Result<()> { |
| self.check_field_count()?; |
| loop { |
| let (res, nout) = self.core.terminator(self.buf.writable()); |
| self.buf.written(nout); |
| match res { |
| WriteResult::InputEmpty => { |
| self.state.fields_written = 0; |
| return Ok(()); |
| } |
| WriteResult::OutputFull => self.flush_buf()?, |
| } |
| } |
| } |
| |
| /// Write a CSV terminator that is guaranteed to fit into the current |
| /// buffer. |
| #[inline(never)] |
| fn write_terminator_into_buffer(&mut self) -> Result<()> { |
| self.check_field_count()?; |
| match self.core.get_terminator() { |
| csv_core::Terminator::CRLF => { |
| self.buf.writable()[0] = b'\r'; |
| self.buf.writable()[1] = b'\n'; |
| self.buf.written(2); |
| } |
| csv_core::Terminator::Any(b) => { |
| self.buf.writable()[0] = b; |
| self.buf.written(1); |
| } |
| _ => unreachable!(), |
| } |
| self.state.fields_written = 0; |
| Ok(()) |
| } |
| |
| fn check_field_count(&mut self) -> Result<()> { |
| if !self.state.flexible { |
| match self.state.first_field_count { |
| None => { |
| self.state.first_field_count = |
| Some(self.state.fields_written); |
| } |
| Some(expected) if expected != self.state.fields_written => { |
| return Err(Error::new(ErrorKind::UnequalLengths { |
| pos: None, |
| expected_len: expected, |
| len: self.state.fields_written, |
| })) |
| } |
| Some(_) => {} |
| } |
| } |
| Ok(()) |
| } |
| } |
| |
| impl Buffer { |
| /// Returns a slice of the buffer's current contents. |
| /// |
| /// The slice returned may be empty. |
| #[inline] |
| fn readable(&self) -> &[u8] { |
| &self.buf[..self.len] |
| } |
| |
| /// Returns a mutable slice of the remaining space in this buffer. |
| /// |
| /// The slice returned may be empty. |
| #[inline] |
| fn writable(&mut self) -> &mut [u8] { |
| &mut self.buf[self.len..] |
| } |
| |
| /// Indicates that `n` bytes have been written to this buffer. |
| #[inline] |
| fn written(&mut self, n: usize) { |
| self.len += n; |
| } |
| |
| /// Clear the buffer. |
| #[inline] |
| fn clear(&mut self) { |
| self.len = 0; |
| } |
| } |
| |
| #[cfg(test)] |
| mod tests { |
| use std::io::{self, Write}; |
| |
| use serde::{serde_if_integer128, Serialize}; |
| |
| use crate::{ |
| byte_record::ByteRecord, error::ErrorKind, string_record::StringRecord, |
| }; |
| |
| use super::{Writer, WriterBuilder}; |
| |
| fn wtr_as_string(wtr: Writer<Vec<u8>>) -> String { |
| String::from_utf8(wtr.into_inner().unwrap()).unwrap() |
| } |
| |
| #[test] |
| fn one_record() { |
| let mut wtr = WriterBuilder::new().from_writer(vec![]); |
| wtr.write_record(&["a", "b", "c"]).unwrap(); |
| |
| assert_eq!(wtr_as_string(wtr), "a,b,c\n"); |
| } |
| |
| #[test] |
| fn one_string_record() { |
| let mut wtr = WriterBuilder::new().from_writer(vec![]); |
| wtr.write_record(&StringRecord::from(vec!["a", "b", "c"])).unwrap(); |
| |
| assert_eq!(wtr_as_string(wtr), "a,b,c\n"); |
| } |
| |
| #[test] |
| fn one_byte_record() { |
| let mut wtr = WriterBuilder::new().from_writer(vec![]); |
| wtr.write_record(&ByteRecord::from(vec!["a", "b", "c"])).unwrap(); |
| |
| assert_eq!(wtr_as_string(wtr), "a,b,c\n"); |
| } |
| |
| #[test] |
| fn raw_one_byte_record() { |
| let mut wtr = WriterBuilder::new().from_writer(vec![]); |
| wtr.write_byte_record(&ByteRecord::from(vec!["a", "b", "c"])).unwrap(); |
| |
| assert_eq!(wtr_as_string(wtr), "a,b,c\n"); |
| } |
| |
| #[test] |
| fn one_empty_record() { |
| let mut wtr = WriterBuilder::new().from_writer(vec![]); |
| wtr.write_record(&[""]).unwrap(); |
| |
| assert_eq!(wtr_as_string(wtr), "\"\"\n"); |
| } |
| |
| #[test] |
| fn raw_one_empty_record() { |
| let mut wtr = WriterBuilder::new().from_writer(vec![]); |
| wtr.write_byte_record(&ByteRecord::from(vec![""])).unwrap(); |
| |
| assert_eq!(wtr_as_string(wtr), "\"\"\n"); |
| } |
| |
| #[test] |
| fn two_empty_records() { |
| let mut wtr = WriterBuilder::new().from_writer(vec![]); |
| wtr.write_record(&[""]).unwrap(); |
| wtr.write_record(&[""]).unwrap(); |
| |
| assert_eq!(wtr_as_string(wtr), "\"\"\n\"\"\n"); |
| } |
| |
| #[test] |
| fn raw_two_empty_records() { |
| let mut wtr = WriterBuilder::new().from_writer(vec![]); |
| wtr.write_byte_record(&ByteRecord::from(vec![""])).unwrap(); |
| wtr.write_byte_record(&ByteRecord::from(vec![""])).unwrap(); |
| |
| assert_eq!(wtr_as_string(wtr), "\"\"\n\"\"\n"); |
| } |
| |
| #[test] |
| fn unequal_records_bad() { |
| let mut wtr = WriterBuilder::new().from_writer(vec![]); |
| wtr.write_record(&ByteRecord::from(vec!["a", "b", "c"])).unwrap(); |
| let err = wtr.write_record(&ByteRecord::from(vec!["a"])).unwrap_err(); |
| match *err.kind() { |
| ErrorKind::UnequalLengths { ref pos, expected_len, len } => { |
| assert!(pos.is_none()); |
| assert_eq!(expected_len, 3); |
| assert_eq!(len, 1); |
| } |
| ref x => { |
| panic!("expected UnequalLengths error, but got '{:?}'", x); |
| } |
| } |
| } |
| |
| #[test] |
| fn raw_unequal_records_bad() { |
| let mut wtr = WriterBuilder::new().from_writer(vec![]); |
| wtr.write_byte_record(&ByteRecord::from(vec!["a", "b", "c"])).unwrap(); |
| let err = |
| wtr.write_byte_record(&ByteRecord::from(vec!["a"])).unwrap_err(); |
| match *err.kind() { |
| ErrorKind::UnequalLengths { ref pos, expected_len, len } => { |
| assert!(pos.is_none()); |
| assert_eq!(expected_len, 3); |
| assert_eq!(len, 1); |
| } |
| ref x => { |
| panic!("expected UnequalLengths error, but got '{:?}'", x); |
| } |
| } |
| } |
| |
| #[test] |
| fn unequal_records_ok() { |
| let mut wtr = WriterBuilder::new().flexible(true).from_writer(vec![]); |
| wtr.write_record(&ByteRecord::from(vec!["a", "b", "c"])).unwrap(); |
| wtr.write_record(&ByteRecord::from(vec!["a"])).unwrap(); |
| assert_eq!(wtr_as_string(wtr), "a,b,c\na\n"); |
| } |
| |
| #[test] |
| fn raw_unequal_records_ok() { |
| let mut wtr = WriterBuilder::new().flexible(true).from_writer(vec![]); |
| wtr.write_byte_record(&ByteRecord::from(vec!["a", "b", "c"])).unwrap(); |
| wtr.write_byte_record(&ByteRecord::from(vec!["a"])).unwrap(); |
| assert_eq!(wtr_as_string(wtr), "a,b,c\na\n"); |
| } |
| |
| #[test] |
| fn full_buffer_should_not_flush_underlying() { |
| struct MarkWriteAndFlush(Vec<u8>); |
| |
| impl MarkWriteAndFlush { |
| fn to_str(self) -> String { |
| String::from_utf8(self.0).unwrap() |
| } |
| } |
| |
| impl Write for MarkWriteAndFlush { |
| fn write(&mut self, data: &[u8]) -> io::Result<usize> { |
| self.0.write(b">")?; |
| let written = self.0.write(data)?; |
| self.0.write(b"<")?; |
| |
| Ok(written) |
| } |
| |
| fn flush(&mut self) -> io::Result<()> { |
| self.0.write(b"!")?; |
| Ok(()) |
| } |
| } |
| |
| let underlying = MarkWriteAndFlush(vec![]); |
| let mut wtr = |
| WriterBuilder::new().buffer_capacity(4).from_writer(underlying); |
| |
| wtr.write_byte_record(&ByteRecord::from(vec!["a", "b"])).unwrap(); |
| wtr.write_byte_record(&ByteRecord::from(vec!["c", "d"])).unwrap(); |
| wtr.flush().unwrap(); |
| wtr.write_byte_record(&ByteRecord::from(vec!["e", "f"])).unwrap(); |
| |
| let got = wtr.into_inner().unwrap().to_str(); |
| |
| // As the buffer size is 4 we should write each record separately, and |
| // flush when explicitly called and implictly in into_inner. |
| assert_eq!(got, ">a,b\n<>c,d\n<!>e,f\n<!"); |
| } |
| |
| #[test] |
| fn serialize_with_headers() { |
| #[derive(Serialize)] |
| struct Row { |
| foo: i32, |
| bar: f64, |
| baz: bool, |
| } |
| |
| let mut wtr = WriterBuilder::new().from_writer(vec![]); |
| wtr.serialize(Row { foo: 42, bar: 42.5, baz: true }).unwrap(); |
| assert_eq!(wtr_as_string(wtr), "foo,bar,baz\n42,42.5,true\n"); |
| } |
| |
| #[test] |
| fn serialize_no_headers() { |
| #[derive(Serialize)] |
| struct Row { |
| foo: i32, |
| bar: f64, |
| baz: bool, |
| } |
| |
| let mut wtr = |
| WriterBuilder::new().has_headers(false).from_writer(vec![]); |
| wtr.serialize(Row { foo: 42, bar: 42.5, baz: true }).unwrap(); |
| assert_eq!(wtr_as_string(wtr), "42,42.5,true\n"); |
| } |
| |
| serde_if_integer128! { |
| #[test] |
| fn serialize_no_headers_128() { |
| #[derive(Serialize)] |
| struct Row { |
| foo: i128, |
| bar: f64, |
| baz: bool, |
| } |
| |
| let mut wtr = |
| WriterBuilder::new().has_headers(false).from_writer(vec![]); |
| wtr.serialize(Row { |
| foo: 9_223_372_036_854_775_808, |
| bar: 42.5, |
| baz: true, |
| }).unwrap(); |
| assert_eq!(wtr_as_string(wtr), "9223372036854775808,42.5,true\n"); |
| } |
| } |
| |
| #[test] |
| fn serialize_tuple() { |
| let mut wtr = WriterBuilder::new().from_writer(vec![]); |
| wtr.serialize((true, 1.3, "hi")).unwrap(); |
| assert_eq!(wtr_as_string(wtr), "true,1.3,hi\n"); |
| } |
| } |
