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use std::fs; use std::io; use std::path::Path; use std::str; use rustc_serialize::Decodable; use { ByteString, Result, Decoded, Error, LocatableError, ParseError, }; use self::State::*; const BUF_SIZE: usize = 1024 * 128; /// A record terminator. /// /// Ideally, this would just be a `u8` like any other delimiter, but a useful /// CSV parser must special case CRLF handling. Hence, this enum. /// /// Generally, you won't need to use this type because `CRLF` is the default, /// which is by far the most widely used record terminator. #[derive(Clone, Copy)] pub enum RecordTerminator { /// Parses `\r`, `\n` or `\r\n` as a single record terminator. CRLF, /// Parses the byte given as a record terminator. Any(u8), } impl RecordTerminator { #[inline] fn is_crlf(&self) -> bool { match *self { RecordTerminator::CRLF => true, RecordTerminator::Any(_) => false, } } } impl PartialEq<u8> for RecordTerminator { #[inline] fn eq(&self, &other: &u8) -> bool { match *self { RecordTerminator::CRLF => other == b'\r' || other == b'\n', RecordTerminator::Any(b) => other == b } } } /// A CSV reader. /// /// This reader parses CSV data and exposes records via iterators. /// /// ### Example /// /// This example shows how to do type-based decoding for each record in the /// CSV data. /// /// ```rust /// let data = " /// sticker,mortals,7 /// bribed,personae,7 /// wobbling,poncing,4 /// interposed,emmett,9 /// chocolate,refile,7"; /// /// let mut rdr = csv::Reader::from_string(data).has_headers(false); /// for row in rdr.decode() { /// let (n1, n2, dist): (String, String, u32) = row.unwrap(); /// println!("{}, {}: {}", n1, n2, dist); /// } /// ``` /// /// Here's another example that parses tab-delimited values with records of /// varying length: /// /// ```rust /// let data = " /// sticker\tmortals\t7 /// bribed\tpersonae\t7 /// wobbling /// interposed\temmett\t9 /// chocolate\trefile\t7"; /// /// let mut rdr = csv::Reader::from_string(data) /// .has_headers(false) /// .delimiter(b'\t') /// .flexible(true); /// for row in rdr.records() { /// let row = row.unwrap(); /// println!("{:?}", row); /// } /// ``` pub struct Reader<R> { rdr: R, buf: Vec<u8>, bufi: usize, fieldbuf: Vec<u8>, state: State, eof: bool, first_row: Vec<ByteString>, first_row_done: bool, irecord: u64, ifield: u64, byte_offset: u64, delimiter: u8, quote: u8, escape: Option<u8>, double_quote: bool, record_term: RecordTerminator, flexible: bool, // When this is true, the first record is interpreted as a "header" row. // This is opaque to the raw iterator, but is used in any iterator that // allocates. // // TODO: This is exposed for use in the `index` sub-module. Is that OK? #[doc(hidden)] pub has_headers: bool, has_seeked: bool, } impl<R: io::Read> Reader<R> { /// Creates a new CSV reader from an arbitrary `io::Read`. /// /// The reader is buffered for you automatically. pub fn from_reader(rdr: R) -> Reader<R> { Reader { rdr: rdr, buf: vec![0; BUF_SIZE], bufi: BUF_SIZE, fieldbuf: Vec::with_capacity(1024), state: StartRecord, eof: false, first_row: vec![], first_row_done: false, irecord: 1, ifield: 1, byte_offset: 0, delimiter: b',', quote: b'"', escape: None, double_quote: true, record_term: RecordTerminator::CRLF, flexible: false, has_headers: true, has_seeked: false, } } } impl Reader<fs::File> { /// Creates a new CSV reader for the data at the file path given. pub fn from_file<P: AsRef<Path>>(path: P) -> Result<Reader<fs::File>> { Ok(Reader::from_reader(try!(fs::File::open(path)))) } } impl Reader<io::Cursor<Vec<u8>>> { /// Creates a CSV reader for an in memory string buffer. pub fn from_string<'a, S>(s: S) -> Reader<io::Cursor<Vec<u8>>> where S: Into<String> { Reader::from_bytes(s.into().into_bytes()) } /// Creates a CSV reader for an in memory buffer of bytes. pub fn from_bytes<'a, V>(bytes: V) -> Reader<io::Cursor<Vec<u8>>> where V: Into<Vec<u8>> { Reader::from_reader(io::Cursor::new(bytes.into())) } } impl<R: io::Read> Reader<R> { /// Uses type-based decoding to read a single record from CSV data. /// /// The type that is being decoded into should correspond to *one full /// CSV record*. A tuple, struct or `Vec` fit this category. A tuple, /// struct or `Vec` should consist of primitive types like integers, /// floats, characters and strings which map to single fields. If a field /// cannot be decoded into the type requested, an error is returned. /// /// Enums are also supported in a limited way. Namely, its variants must /// have exactly `1` parameter each. Each variant decodes based on its /// constituent type and variants are tried in the order that they appear /// in their `enum` definition. See below for examples. /// /// ### Examples /// /// This example shows how to decode records into a struct. (Note that /// currently, the *names* of the struct members are irrelevant.) /// /// ```rust /// extern crate rustc_serialize; /// # extern crate csv; /// # fn main() { /// /// #[derive(RustcDecodable)] /// struct Pair { /// name1: String, /// name2: String, /// dist: u32, /// } /// /// let mut rdr = csv::Reader::from_string("foo,bar,1\nfoo,baz,2") /// .has_headers(false); /// // Instantiating a specific type when decoding is usually necessary. /// let rows = rdr.decode().collect::<csv::Result<Vec<Pair>>>().unwrap(); /// /// assert_eq!(rows[0].dist, 1); /// assert_eq!(rows[1].dist, 2); /// # } /// ``` /// /// We can get a little crazier with custon enum types or `Option` types. /// An `Option` type in particular is useful when a column doesn't contain /// valid data in every record (whether it be empty or malformed). /// /// ```rust /// extern crate rustc_serialize; /// # extern crate csv; /// # fn main() { /// /// #[derive(RustcDecodable, PartialEq, Debug)] /// struct MyUint(u32); /// /// #[derive(RustcDecodable, PartialEq, Debug)] /// enum Number { Integer(i64), Float(f64) } /// /// #[derive(RustcDecodable)] /// struct Row { /// name1: String, /// name2: String, /// dist: Option<MyUint>, /// dist2: Number, /// } /// /// let mut rdr = csv::Reader::from_string("foo,bar,1,1\nfoo,baz,,1.5") /// .has_headers(false); /// let rows = rdr.decode().collect::<csv::Result<Vec<Row>>>().unwrap(); /// /// assert_eq!(rows[0].dist, Some(MyUint(1))); /// assert_eq!(rows[1].dist, None); /// assert_eq!(rows[0].dist2, Number::Integer(1)); /// assert_eq!(rows[1].dist2, Number::Float(1.5)); /// # } /// ``` /// /// Finally, as a special case, a tuple/struct/`Vec` can be used as the /// "tail" of another tuple/struct/`Vec` to capture all remaining fields: /// /// ```rust /// extern crate rustc_serialize; /// # extern crate csv; /// # fn main() { /// /// #[derive(RustcDecodable)] /// struct Pair { /// name1: String, /// name2: String, /// attrs: Vec<u32>, /// } /// /// let mut rdr = csv::Reader::from_string("a,b,1,2,3,4\ny,z,5,6,7,8") /// .has_headers(false); /// let rows = rdr.decode().collect::<csv::Result<Vec<Pair>>>().unwrap(); /// /// assert_eq!(rows[0].attrs, vec![1,2,3,4]); /// assert_eq!(rows[1].attrs, vec![5,6,7,8]); /// # } /// ``` /// /// If a tuple/struct/`Vec` appears any where other than the "tail" of a /// record, then the behavior is undefined. (You'll likely get a runtime /// error. I believe this is a limitation of the current decoding machinery /// in the `serialize` crate.) /// ``` pub fn decode<'a, D: Decodable>(&'a mut self) -> DecodedRecords<'a, R, D> { DecodedRecords { p: self.byte_records(), _phantom: ::std::marker::PhantomData, } } /// Returns an iterator of records in the CSV data where each field is /// a `String`. /// /// ### Example /// /// This is your standard CSV interface with no type decoding magic. /// /// ```rust /// let data = " /// sticker,mortals,7 /// bribed,personae,7 /// wobbling,poncing,4 /// interposed,emmett,9 /// chocolate,refile,7"; /// /// let mut rdr = csv::Reader::from_string(data).has_headers(false); /// for row in rdr.records() { /// let row = row.unwrap(); /// println!("{:?}", row); /// } /// ``` pub fn records<'a>(&'a mut self) -> StringRecords<'a, R> { StringRecords { p: self.byte_records() } } /// Returns a *copy* of the first record in the CSV data as strings. /// /// This method may be called at any time and regardless of whether /// `no_headers` is set or not. /// /// ### Example /// /// ```rust /// let mut rdr = csv::Reader::from_string("a,b,c\n1,2,3"); /// /// let headers1 = rdr.headers().unwrap(); /// let rows = rdr.records().collect::<csv::Result<Vec<_>>>().unwrap(); /// let headers2 = rdr.headers().unwrap(); /// /// let s = |s: &'static str| s.to_string(); /// assert_eq!(headers1, headers2); /// assert_eq!(headers1, vec![s("a"), s("b"), s("c")]); /// assert_eq!(rows.len(), 1); /// assert_eq!(rows[0], vec![s("1"), s("2"), s("3")]); /// ``` /// /// Note that if `no_headers` is called on the CSV reader, the rows /// returned in this example include the first record: /// /// ```rust /// let mut rdr = csv::Reader::from_string("a,b,c\n1,2,3") /// .has_headers(false); /// /// let headers1 = rdr.headers().unwrap(); /// let rows = rdr.records().collect::<csv::Result<Vec<_>>>().unwrap(); /// let headers2 = rdr.headers().unwrap(); /// /// let s = |s: &'static str| s.to_string(); /// assert_eq!(headers1, headers2); /// assert_eq!(headers1, vec![s("a"), s("b"), s("c")]); /// /// // The header rows are now part of the record iterators. /// assert_eq!(rows.len(), 2); /// assert_eq!(rows[0], headers1); /// assert_eq!(rows[1], vec![s("1"), s("2"), s("3")]); /// ``` pub fn headers(&mut self) -> Result<Vec<String>> { byte_record_to_utf8(try!(self.byte_headers())) } } impl<R: io::Read> Reader<R> { /// The delimiter to use when reading CSV data. /// /// Since the CSV reader is meant to be mostly encoding agnostic, you must /// specify the delimiter as a single ASCII byte. For example, to read /// tab-delimited data, you would use `b'\t'`. /// /// The default value is `b','`. pub fn delimiter(mut self, delimiter: u8) -> Reader<R> { self.delimiter = delimiter; self } /// Whether to treat the first row as a special header row. /// /// By default, the first row is treated as a special header row, which /// means it is excluded from iterators returned by the `decode`, `records` /// or `byte_records` methods. When `yes` is set to `false`, the first row /// is included in those iterators. /// /// Note that the `headers` method is unaffected by whether this is set. pub fn has_headers(mut self, yes: bool) -> Reader<R> { self.has_headers = yes; self } /// Whether to allow flexible length records when reading CSV data. /// /// When this is set to `true`, records in the CSV data can have different /// lengths. By default, this is disabled, which will cause the CSV reader /// to return an error if it tries to read a record that has a different /// length than the first record that it read. pub fn flexible(mut self, yes: bool) -> Reader<R> { self.flexible = yes; self } /// Set the record terminator to use when reading CSV data. /// /// In the vast majority of situations, you'll want to use the default /// value, `RecordTerminator::CRLF`, which automatically handles `\r`, /// `\n` or `\r\n` as record terminators. (Notably, this is a special /// case since two characters can correspond to a single terminator token.) /// /// However, you may use `RecordTerminator::Any` to specify any ASCII /// character to use as the record terminator. For example, you could /// use `RecordTerminator::Any(b'\n')` to only accept line feeds as /// record terminators, or `b'\x1e'` for the ASCII record separator. pub fn record_terminator(mut self, term: RecordTerminator) -> Reader<R> { self.record_term = term; self } /// Set the quote character to use when reading CSV data. /// /// Since the CSV reader is meant to be mostly encoding agnostic, you must /// specify the quote as a single ASCII byte. For example, to read /// single quoted data, you would use `b'\''`. /// /// The default value is `b'"'`. /// /// If `quote` is `None`, then no quoting will be used. pub fn quote(mut self, quote: u8) -> Reader<R> { self.quote = quote; self } /// Set the escape character to use when reading CSV data. /// /// Since the CSV reader is meant to be mostly encoding agnostic, you must /// specify the escape as a single ASCII byte. /// /// When set to `None` (which is the default), the "doubling" escape /// is used for quote character. /// /// When set to something other than `None`, it is used as the escape /// character for quotes. (e.g., `b'\\'`.) pub fn escape(mut self, escape: Option<u8>) -> Reader<R> { self.escape = escape; self } /// Enable double quote escapes. /// /// When disabled, doubled quotes are not interpreted as escapes. pub fn double_quote(mut self, yes: bool) -> Reader<R> { self.double_quote = yes; self } /// A convenience method for reading ASCII delimited text. /// /// This sets the delimiter and record terminator to the ASCII unit /// separator (`\x1f`) and record separator (`\x1e`), respectively. /// /// Since ASCII delimited text is meant to be unquoted, this also sets /// `quote` to `None`. pub fn ascii(self) -> Reader<R> { self.delimiter(b'\x1f') .record_terminator(RecordTerminator::Any(b'\x1e')) } } /// NextField is the result of parsing a single CSV field. /// /// This is only useful if you're using the low level `next_bytes` method. #[derive(Debug)] pub enum NextField<'a, T: ?Sized + 'a> { /// A single CSV field as a borrowed slice of the parser's internal buffer. Data(&'a T), /// A CSV error found during parsing. When an error is found, it is /// first returned. All subsequent calls of `next_bytes` will return /// `EndOfCsv`. (EOF is exempt from this. Depending on the state of the /// parser, an EOF could trigger `Data`, `EndOfRecord` and `EndOfCsv`, /// all in succession.) /// /// In general, once `EndOfCsv` is returned, no other return value is /// possible on subsequent calls. Error(Error), /// Indicates the end of a record. EndOfRecord, /// Indicates the end of the CSV data. Once this state is entered, the /// parser can never leave it. EndOfCsv, } impl<'a, T: ?Sized + ::std::fmt::Debug> NextField<'a, T> { /// Transform NextField into an iterator result. pub fn into_iter_result(self) -> Option<Result<&'a T>> { match self { NextField::EndOfRecord | NextField::EndOfCsv => None, NextField::Error(err) => Some(Err(err)), NextField::Data(field) => Some(Ok(field)), } } /// Returns true if and only if the end of CSV data has been reached. pub fn is_end(&self) -> bool { if let NextField::EndOfCsv = *self { true } else { false } } /// Returns the underlying field data. /// /// If `NextField` is an error or an end of record/CSV marker, this will /// panic. pub fn unwrap(self) -> &'a T { match self { NextField::Data(field) => field, v => panic!("Cannot unwrap '{:?}'", v), } } } /// These are low level methods for dealing with the raw bytes of CSV records. /// You should only need to use these when you need the performance or if /// your CSV data isn't UTF-8 encoded. impl<R: io::Read> Reader<R> { /// This is just like `headers`, except fields are `ByteString`s instead /// of `String`s. pub fn byte_headers(&mut self) -> Result<Vec<ByteString>> { if !self.first_row.is_empty() { Ok(self.first_row.clone()) } else { let mut headers = vec![]; loop { let field = match self.next_bytes() { NextField::EndOfRecord | NextField::EndOfCsv => break, NextField::Error(err) => return Err(err), NextField::Data(field) => field, }; headers.push(field.to_vec()); } assert!(headers.len() > 0 || self.done()); Ok(headers) } } /// This is just like `records`, except fields are `ByteString`s instead /// of `String`s. pub fn byte_records<'a>(&'a mut self) -> ByteRecords<'a, R> { let first = self.has_seeked; ByteRecords { p: self, first: first, errored: false } } /// Returns `true` if the CSV parser has reached its final state. When /// this method returns `true`, all iterators will always return `None`. /// /// This is not needed in typical usage since the record iterators will /// stop for you when the parser completes. This method is useful when /// you're accessing the parser's lowest-level iterator. /// /// ### Example /// /// This is the *fastest* way to compute the number of records in CSV data /// using this crate. (It is fast because it does not allocate space for /// every field.) /// /// ```rust /// let data = " /// sticker,mortals,7 /// bribed,personae,7 /// wobbling,poncing,4 /// interposed,emmett,9 /// chocolate,refile,7"; /// /// let mut rdr = csv::Reader::from_string(data); /// let mut count = 0u64; /// while !rdr.done() { /// loop { /// // This case analysis is necessary because we only want to /// // increment the count when `EndOfRecord` is seen. (If the /// // CSV data is empty, then it will never be emitted.) /// match rdr.next_bytes() { /// csv::NextField::EndOfCsv => break, /// csv::NextField::EndOfRecord => { count += 1; break; }, /// csv::NextField::Error(err) => panic!(err), /// csv::NextField::Data(_) => {} /// } /// } /// } /// /// assert_eq!(count, 5); /// ``` pub fn done(&self) -> bool { self.eof } /// An iterator over fields in the current record. /// /// This provides low level access to CSV records as raw byte slices. /// Namely, no allocation is performed. Unlike other iterators in this /// crate, this yields *fields* instead of records. Notably, this cannot /// implement the `Iterator` trait safely. As such, it cannot be used with /// a `for` loop. /// /// See the documentation for the `NextField` type on how the iterator /// works. /// /// This iterator always returns all records (i.e., it won't skip the /// header row). /// /// ### Example /// /// This method is most useful when used in conjunction with the the /// `done` method: /// /// ```rust /// let data = " /// sticker,mortals,7 /// bribed,personae,7 /// wobbling,poncing,4 /// interposed,emmett,9 /// chocolate,refile,7"; /// /// let mut rdr = csv::Reader::from_string(data); /// while !rdr.done() { /// while let Some(r) = rdr.next_bytes().into_iter_result() { /// print!("{:?} ", r.unwrap()); /// } /// println!(""); /// } /// ``` pub fn next_bytes(&mut self) -> NextField<[u8]> { unsafe { self.fieldbuf.set_len(0); } loop { if let Err(err) = self.fill_buf() { return NextField::Error(Error::Io(err)); } if self.buf.len() == 0 { self.eof = true; if let StartRecord = self.state { return self.next_eoc(); } else if let EndRecord = self.state { self.state = StartRecord; return self.next_eor(); } else { self.state = EndRecord; return self.next_data(); } } while self.bufi < self.buf.len() { let c = self.buf[self.bufi]; match self.state { StartRecord => { if self.is_record_term(c) { self.bump(); } else { self.state = StartField; } } EndRecord => { if self.record_term.is_crlf() && c == b'\n' { self.bump(); } self.state = StartRecord; return self.next_eor(); } StartField => { self.bump(); if c == self.quote { self.state = InQuotedField; } else if c == self.delimiter { return self.next_data(); } else if self.is_record_term(c) { self.state = EndRecord; return self.next_data(); } else { self.add(c); self.state = InField; } } InField => { self.bump(); if c == self.delimiter { self.state = StartField; return self.next_data(); } else if self.is_record_term(c) { self.state = EndRecord; return self.next_data(); } else { self.add(c); } } InQuotedField => { self.bump(); if c == self.quote { self.state = InDoubleEscapedQuote; } else if self.escape == Some(c) { self.state = InEscapedQuote; } else { self.add(c); } } InEscapedQuote => { self.bump(); self.add(c); self.state = InQuotedField; } InDoubleEscapedQuote => { self.bump(); if self.double_quote && c == self.quote { self.add(c); self.state = InQuotedField; } else if c == self.delimiter { self.state = StartField; return self.next_data(); } else if self.is_record_term(c) { self.state = EndRecord; return self.next_data(); } else { self.add(c); self.state = InField; // degrade gracefully? } } } } } } /// This is just like `next_bytes` except it converts each field to /// a Unicode string in place. pub fn next_str(&mut self) -> NextField<str> { // This really grates me. Once we call `next_bytes`, we initiate a // *mutable* borrow of `self` that doesn't stop until the return value // goes out of scope. Since we have to return that value, it will never // go out of scope in this function. // // Therefore, we can't get access to any state information after // calling `next_bytes`. But we might need it to report an error. // // One possible way around this is to use interior mutability... let (record, field) = (self.irecord, self.ifield); match self.next_bytes() { NextField::EndOfRecord => NextField::EndOfRecord, NextField::EndOfCsv => NextField::EndOfCsv, NextField::Error(err) => NextField::Error(err), NextField::Data(bytes) => { match str::from_utf8(bytes) { Ok(s) => NextField::Data(s), Err(_) => NextField::Error(Error::Parse(LocatableError { record: record, field: field, err: ParseError::InvalidUtf8, })), } } } } /// An unsafe iterator over byte fields. /// /// This iterator calls `next_bytes` at each step. /// /// It is (wildly) unsafe because the lifetime yielded for each element /// is incorrect. It refers to the lifetime of the CSV reader instead of /// the lifetime of the internal buffer. Which means you can `collect` /// it into a vector and obliterate memory safety. /// /// The reason it exists is because it appears extremely difficult to write /// a fast streaming iterator. (But iterators are wildly convenient.) #[doc(hidden)] pub unsafe fn byte_fields<'a>(&'a mut self) -> UnsafeByteFields<'a, R> { UnsafeByteFields { rdr: self } } /// Returns the byte offset at which the current record started. pub fn byte_offset(&self) -> u64 { self.byte_offset } #[inline] fn next_data(&mut self) -> NextField<[u8]> { if !self.first_row_done { self.first_row.push(self.fieldbuf.to_vec()); } self.ifield += 1; NextField::Data(&self.fieldbuf) } #[inline] fn next_eor(&mut self) -> NextField<[u8]> { if !self.flexible && self.first_row_done && self.ifield != self.first_row.len() as u64 { return self.parse_error(ParseError::UnequalLengths { expected: self.first_row.len() as u64, got: self.ifield as u64, }); } self.irecord += 1; self.ifield = 0; self.first_row_done = true; NextField::EndOfRecord } #[inline] fn next_eoc(&self) -> NextField<[u8]> { NextField::EndOfCsv } #[inline] fn fill_buf(&mut self) -> io::Result<()> { if self.bufi == self.buf.len() { unsafe { let cap = self.buf.capacity(); self.buf.set_len(cap); } let n = try!(self.rdr.read(&mut self.buf)); unsafe { self.buf.set_len(n); } self.bufi = 0; } Ok(()) } #[inline] fn bump(&mut self) { self.bufi += 1; self.byte_offset += 1; } #[inline] fn add(&mut self, c: u8) { self.fieldbuf.push(c); } #[inline] fn is_record_term(&self, c: u8) -> bool { self.record_term == c } fn parse_error(&self, err: ParseError) -> NextField<[u8]> { NextField::Error(Error::Parse(LocatableError { record: self.irecord, field: self.ifield, err: err, })) } } #[derive(Debug)] enum State { StartRecord, EndRecord, StartField, InField, InQuotedField, InEscapedQuote, InDoubleEscapedQuote, } impl<R: io::Read + io::Seek> Reader<R> { /// Seeks the underlying reader to the file cursor specified. /// /// This comes with several caveats: /// /// * The existing buffer is dropped and a new one is created. /// * If you seek to a position other than the start of a record, you'll /// probably get an incorrect parse. (This is *not* unsafe.) /// /// Mostly, this is intended for use with the `index` sub module. /// /// Note that if `pos` is equivalent to the current *parsed* byte offset, /// then no seeking is performed. (In this case, `seek` is a no-op.) pub fn seek(&mut self, pos: u64) -> Result<()> { self.has_seeked = true; self.state = StartRecord; if pos == self.byte_offset() { return Ok(()) } self.bufi = self.buf.len(); // will force a buffer refresh self.eof = false; self.byte_offset = pos; try!(self.rdr.seek(io::SeekFrom::Start(pos))); Ok(()) } } #[doc(hidden)] pub struct UnsafeByteFields<'a, R: 'a> { rdr: &'a mut Reader<R>, } #[doc(hidden)] impl<'a, R> Iterator for UnsafeByteFields<'a, R> where R: io::Read { type Item = Result<&'a [u8]>; fn next(&mut self) -> Option<Result<&'a [u8]>> { unsafe { ::std::mem::transmute(self.rdr.next_bytes().into_iter_result()) } } } /// An iterator of decoded records. /// /// The lifetime parameter `'a` refers to the lifetime of the underlying /// CSV reader. /// /// The `R` type parameter refers to the type of the underlying reader. /// /// The `D` type parameter refers to the decoded type. pub struct DecodedRecords<'a, R: 'a, D> { p: ByteRecords<'a, R>, _phantom: ::std::marker::PhantomData<D>, } impl<'a, R, D> Iterator for DecodedRecords<'a, R, D> where R: io::Read, D: Decodable { type Item = Result<D>; fn next(&mut self) -> Option<Result<D>> { self.p.next().map(|res| { res.and_then(|byte_record| { Decodable::decode(&mut Decoded::new(byte_record)) }) }) } } /// An iterator of `String` records. /// /// The lifetime parameter `'a` refers to the lifetime of the underlying /// CSV reader. /// /// The `R` type parameter refers to the type of the underlying reader. pub struct StringRecords<'a, R: 'a> { p: ByteRecords<'a, R>, } impl<'a, R> Iterator for StringRecords<'a, R> where R: io::Read { type Item = Result<Vec<String>>; fn next(&mut self) -> Option<Result<Vec<String>>> { self.p.next().map(|res| { res.and_then(|byte_record| { byte_record_to_utf8(byte_record) }) }) } } /// An iterator of `ByteString` records. /// /// The lifetime parameter `'a` refers to the lifetime of the underlying /// CSV reader. /// /// The `R` type parameter refers to the type of the underlying reader. pub struct ByteRecords<'a, R: 'a> { p: &'a mut Reader<R>, first: bool, errored: bool, } impl<'a, R> Iterator for ByteRecords<'a, R> where R: io::Read { type Item = Result<Vec<ByteString>>; fn next(&mut self) -> Option<Result<Vec<ByteString>>> { // We check this before checking `done` because the parser could // be done after a call to `byte_headers` but before any iterator // traversal. Once we start the iterator, we must allow the first // row to be returned if the caller has said that this CSV data // has no headers. if !self.first { // Never do this special first record processing again. self.first = true; // Always consume the header record. This let's us choose to // return it or ignore it and move on to the next record. // If headers have been read before this point, then this is // equivalent to a harmless clone (and no parser progression). let headers = self.p.byte_headers(); // If the header row is empty, then the CSV data contains // no records. Never return zero-length records! if headers.as_ref().map(|r| r.is_empty()).unwrap_or(false) { assert!(self.p.done()); return None; } // This is important. If the client says this CSV data has no // headers but calls `headers` before iterating records (which is // perfectly valid), then we need to make sure to return that // first record. // // If the client says the CSV data has headers, then the first // record should always be ignored. if !self.p.has_headers { return Some(headers); } } // OK, we're done checking the weird first-record-corner-case. if self.p.done() || self.errored { return None; } let mut record = Vec::with_capacity(self.p.first_row.len()); loop { match self.p.next_bytes() { NextField::EndOfRecord | NextField::EndOfCsv => { if record.len() == 0 { return None } break } NextField::Error(err) => { self.errored = true; return Some(Err(err)); } NextField::Data(field) => record.push(field.to_vec()), } } Some(Ok(record)) } } fn byte_record_to_utf8(record: Vec<ByteString>) -> Result<Vec<String>> { for bytes in record.iter() { if let Err(err) = ::std::str::from_utf8(&**bytes) { return Err(Error::Decode(format!( "Could not decode the following bytes as UTF-8 \ because {}: {:?}", err.to_string(), bytes))); } } Ok(unsafe { ::std::mem::transmute(record) }) }