setting up facets

Cargo.lock

@@ -138,15 +138,16 @@ dependencies = [
 
 [[package]]
 name = "actix-rt"
-version = "1.1.0"
+version = "1.1.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "20066d9200ef8d441ac156c76dd36c3f1e9a15976c34e69ae97f7f570b331882"
+checksum = "143fcc2912e0d1de2bcf4e2f720d2a60c28652ab4179685a1ee159e0fb3db227"
 dependencies = [
  "actix-macros",
  "actix-threadpool",
  "copyless",
  "futures-channel",
  "futures-util",
+ "smallvec",
  "tokio",
 ]
 
@@ -309,12 +310,9 @@ checksum = "5d2e7343e7fc9de883d1b0341e0b13970f764c14101234857d2ddafa1cb1cac2"
 
 [[package]]
 name = "ahash"
-version = "0.3.3"
+version = "0.3.4"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "35b909d1c126f78ace756fc337133356c499eebeefcce930fa5fb018823f2b2d"
+checksum = "9c251dce3391a07b43218ca070203ecb8f9f520d35ab71312296a59dbceab154"
-dependencies = [
- "const-random",
-]
 
 [[package]]
 name = "aho-corasick"
@@ -436,9 +434,9 @@ dependencies = [
 
 [[package]]
 name = "backtrace-sys"
-version = "0.1.36"
+version = "0.1.37"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "78848718ee1255a2485d1309ad9cdecfc2e7d0362dd11c6829364c6b35ae1bc7"
+checksum = "18fbebbe1c9d1f383a9cc7e8ccdb471b91c8d024ee9c2ca5b5346121fe8b4399"
 dependencies = [
  "cc",
  "libc",
@@ -452,9 +450,9 @@ checksum = "b41b7ea54a0c9d92199de89e20e58d49f02f8e699814ef3fdf266f6f748d15c7"
 
 [[package]]
 name = "base64"
-version = "0.12.0"
+version = "0.12.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "7d5ca2cd0adc3f48f9e9ea5a6bbdf9ccc0bfade884847e484d452414c7ccffb3"
+checksum = "53d1ccbaf7d9ec9537465a97bf19edc1a4e158ecb49fc16178202238c569cc42"
 
 [[package]]
 name = "bincode"
@@ -646,26 +644,6 @@ version = "0.4.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "4ab08c5bed92075075d5db5149887a477b2dc0318c40882a0dfbd34315ac6141"
 
-[[package]]
-name = "const-random"
-version = "0.1.8"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "2f1af9ac737b2dd2d577701e59fd09ba34822f6f2ebdb30a7647405d9e55e16a"
-dependencies = [
- "const-random-macro",
- "proc-macro-hack",
-]
-
-[[package]]
-name = "const-random-macro"
-version = "0.1.8"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "25e4c606eb459dd29f7c57b2e0879f2b6f14ee130918c2b78ccb58a9624e6c7a"
-dependencies = [
- "getrandom",
- "proc-macro-hack",
-]
-
 [[package]]
 name = "copyless"
 version = "0.1.4"
@@ -688,6 +666,12 @@ version = "0.7.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "b3a71ab494c0b5b860bdc8407ae08978052417070c2ced38573a9157ad75b8ac"
 
+[[package]]
+name = "cow-utils"
+version = "0.1.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "79bb3adfaf5f75d24b01aee375f7555907840fa2800e5ec8fa3b9e2031830173"
+
 [[package]]
 name = "crc32fast"
 version = "1.2.0"
@@ -699,16 +683,16 @@ dependencies = [
 
 [[package]]
 name = "criterion"
-version = "0.3.1"
+version = "0.3.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "1fc755679c12bda8e5523a71e4d654b6bf2e14bd838dfc48cde6559a05caf7d1"
+checksum = "63f696897c88b57f4ffe3c69d8e1a0613c7d0e6c4833363c8560fbde9c47b966"
 dependencies = [
  "atty",
  "cast",
  "clap",
  "criterion-plot",
  "csv",
- "itertools 0.8.2",
+ "itertools",
  "lazy_static",
  "num-traits",
  "oorandom",
@@ -724,12 +708,12 @@ dependencies = [
 
 [[package]]
 name = "criterion-plot"
-version = "0.4.1"
+version = "0.4.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "a01e15e0ea58e8234f96146b1f91fa9d0e4dd7a38da93ff7a75d42c0b9d3a545"
+checksum = "ddeaf7989f00f2e1d871a26a110f3ed713632feac17f65f03ca938c542618b60"
 dependencies = [
  "cast",
- "itertools 0.8.2",
+ "itertools",
 ]
 
 [[package]]
@@ -926,9 +910,9 @@ dependencies = [
 
 [[package]]
 name = "failure"
-version = "0.1.7"
+version = "0.1.8"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "b8529c2421efa3066a5cbd8063d2244603824daccb6936b079010bb2aa89464b"
+checksum = "d32e9bd16cc02eae7db7ef620b392808b89f6a5e16bb3497d159c6b92a0f4f86"
 dependencies = [
  "backtrace",
  "failure_derive",
@@ -936,9 +920,9 @@ dependencies = [
 
 [[package]]
 name = "failure_derive"
-version = "0.1.7"
+version = "0.1.8"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "030a733c8287d6213886dd487564ff5c8f6aae10278b3588ed177f9d18f8d231"
+checksum = "aa4da3c766cd7a0db8242e326e9e4e081edd567072893ed320008189715366a4"
 dependencies = [
  "proc-macro2",
  "quote",
@@ -1153,9 +1137,9 @@ dependencies = [
 
 [[package]]
 name = "h2"
-version = "0.2.4"
+version = "0.2.5"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "377038bf3c89d18d6ca1431e7a5027194fbd724ca10592b9487ede5e8e144f42"
+checksum = "79b7246d7e4b979c03fa093da39cfb3617a96bbeee6310af63991668d7e843ff"
 dependencies = [
  "bytes 0.5.4",
  "fnv",
@@ -1172,9 +1156,9 @@ dependencies = [
 
 [[package]]
 name = "hashbrown"
-version = "0.7.1"
+version = "0.7.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "479e9d9a1a3f8c489868a935b557ab5710e3e223836da2ecd52901d88935cb56"
+checksum = "96282e96bfcd3da0d3aa9938bedf1e50df3269b6db08b4876d2da0bb1a0841cf"
 dependencies = [
  "ahash",
  "autocfg",
@@ -1432,9 +1416,9 @@ dependencies = [
 
 [[package]]
 name = "ipconfig"
-version = "0.2.1"
+version = "0.2.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "aa79fa216fbe60834a9c0737d7fcd30425b32d1c58854663e24d4c4b328ed83f"
+checksum = "f7e2f18aece9709094573a9f24f483c4f65caa4298e2f7ae1b71cc65d853fad7"
 dependencies = [
  "socket2",
  "widestring",
@@ -1442,15 +1426,6 @@ dependencies = [
  "winreg",
 ]
 
-[[package]]
-name = "itertools"
-version = "0.8.2"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "f56a2d0bc861f9165be4eb3442afd3c236d8a98afd426f65d92324ae1091a484"
-dependencies = [
- "either",
-]
-
 [[package]]
 name = "itertools"
 version = "0.9.0"
@@ -1489,9 +1464,9 @@ dependencies = [
 
 [[package]]
 name = "js-sys"
-version = "0.3.37"
+version = "0.3.39"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "6a27d435371a2fa5b6d2b028a74bbdb1234f308da363226a2854ca3ff8ba7055"
+checksum = "fa5a448de267e7358beaf4a5d849518fe9a0c13fce7afd44b06e68550e5562a7"
 dependencies = [
  "wasm-bindgen",
 ]
@@ -1535,9 +1510,9 @@ checksum = "99e85c08494b21a9054e7fe1374a732aeadaff3980b6990b94bfd3a70f690005"
 
 [[package]]
 name = "linked-hash-map"
-version = "0.5.2"
+version = "0.5.3"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "ae91b68aebc4ddb91978b11a1b02ddd8602a05ec19002801c5666000e05e0f83"
+checksum = "8dd5a6d5999d9907cda8ed67bbd137d3af8085216c2ac62de5be860bd41f304a"
 
 [[package]]
 name = "lmdb-rkv-sys"
@@ -1617,17 +1592,19 @@ dependencies = [
  "byteorder",
  "chrono",
  "compact_arena",
+ "cow-utils",
  "criterion",
  "crossbeam-channel",
  "csv",
  "deunicode",
+ "either",
  "env_logger",
  "fst",
  "hashbrown",
  "heed",
  "indexmap",
  "intervaltree",
- "itertools 0.9.0",
+ "itertools",
  "jemallocator",
  "levenshtein_automata",
  "log",
@@ -1768,9 +1745,9 @@ dependencies = [
 
 [[package]]
 name = "mio"
-version = "0.6.21"
+version = "0.6.22"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "302dec22bcf6bae6dfb69c647187f4b4d0fb6f535521f7bc022430ce8e12008f"
+checksum = "fce347092656428bc8eaf6201042cb551b8d67855af7374542a92a0fbfcac430"
 dependencies = [
  "cfg-if",
  "fuchsia-zircon",
@@ -1787,9 +1764,9 @@ dependencies = [
 
 [[package]]
 name = "mio-uds"
-version = "0.6.7"
+version = "0.6.8"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "966257a94e196b11bb43aca423754d87429960a768de9414f3691d6957abf125"
+checksum = "afcb699eb26d4332647cc848492bbc15eafb26f08d0304550d5aa1f612e066f0"
 dependencies = [
  "iovec",
  "libc",
@@ -1828,9 +1805,9 @@ dependencies = [
 
 [[package]]
 name = "net2"
-version = "0.2.33"
+version = "0.2.34"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "42550d9fb7b6684a6d404d9fa7250c2eb2646df731d1c06afc06dcee9e1bcf88"
+checksum = "2ba7c918ac76704fb42afcbbb43891e72731f3dcca3bef2a19786297baf14af7"
 dependencies = [
  "cfg-if",
  "libc",
@@ -1906,9 +1883,9 @@ checksum = "b1c601810575c99596d4afc46f78a678c80105117c379eb3650cf99b8a21ce5b"
 
 [[package]]
 name = "oorandom"
-version = "11.1.0"
+version = "11.1.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "ebcec7c9c2a95cacc7cd0ecb89d8a8454eca13906f6deb55258ffff0adeb9405"
+checksum = "94af325bc33c7f60191be4e2c984d48aaa21e2854f473b85398344b60c9b6358"
 
 [[package]]
 name = "opaque-debug"
@@ -2058,18 +2035,18 @@ dependencies = [
 
 [[package]]
 name = "pin-project"
-version = "0.4.9"
+version = "0.4.13"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "6f6a7f5eee6292c559c793430c55c00aea9d3b3d1905e855806ca4d7253426a2"
+checksum = "82c3bfbfb5bb42f99498c7234bbd768c220eb0cea6818259d0d18a1aa3d2595d"
 dependencies = [
  "pin-project-internal",
 ]
 
 [[package]]
 name = "pin-project-internal"
-version = "0.4.9"
+version = "0.4.13"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "8988430ce790d8682672117bc06dda364c0be32d3abd738234f19f3240bad99a"
+checksum = "ccbf6449dcfb18562c015526b085b8df1aa3cdab180af8ec2ebd300a3bd28f63"
 dependencies = [
  "proc-macro2",
  "quote",
@@ -2078,9 +2055,9 @@ dependencies = [
 
 [[package]]
 name = "pin-project-lite"
-version = "0.1.4"
+version = "0.1.5"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "237844750cfbb86f67afe27eee600dfbbcb6188d734139b534cbfbf4f96792ae"
+checksum = "f7505eeebd78492e0f6108f7171c4948dbb120ee8119d9d77d0afa5469bef67f"
 
 [[package]]
 name = "pin-utils"
@@ -2096,9 +2073,9 @@ checksum = "05da548ad6865900e60eaba7f589cc0783590a92e940c26953ff81ddbab2d677"
 
 [[package]]
 name = "plotters"
-version = "0.2.12"
+version = "0.2.14"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "4e3bb8da247d27ae212529352020f3e5ee16e83c0c258061d27b08ab92675eeb"
+checksum = "f9b1d9ca091d370ea3a78d5619145d1b59426ab0c9eedbad2514a4cee08bf389"
 dependencies = [
  "js-sys",
  "num-traits",
@@ -2162,9 +2139,9 @@ checksum = "8e946095f9d3ed29ec38de908c22f95d9ac008e424c7bcae54c75a79c527c694"
 
 [[package]]
 name = "proc-macro2"
-version = "1.0.10"
+version = "1.0.12"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "df246d292ff63439fea9bc8c0a270bed0e390d5ebd4db4ba15aba81111b5abe3"
+checksum = "8872cf6f48eee44265156c111456a700ab3483686b3f96df4cf5481c89157319"
 dependencies = [
  "unicode-xid",
 ]
@@ -2186,9 +2163,9 @@ checksum = "a1d01941d82fa2ab50be1e79e6714289dd7cde78eba4c074bc5a4374f650dfe0"
 
 [[package]]
 name = "quote"
-version = "1.0.3"
+version = "1.0.4"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "2bdc6c187c65bca4260c9011c9e3132efe4909da44726bad24cf7572ae338d7f"
+checksum = "4c1f4b0efa5fc5e8ceb705136bfee52cfdb6a4e3509f770b478cd6ed434232a7"
 dependencies = [
  "proc-macro2",
 ]
@@ -2398,13 +2375,13 @@ dependencies = [
 
 [[package]]
 name = "ring"
-version = "0.16.12"
+version = "0.16.13"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "1ba5a8ec64ee89a76c98c549af81ff14813df09c3e6dc4766c3856da48597a0c"
+checksum = "703516ae74571f24b465b4a1431e81e2ad51336cb0ded733a55a1aa3eccac196"
 dependencies = [
  "cc",
- "lazy_static",
  "libc",
+ "once_cell",
  "spin",
  "untrusted",
  "web-sys",
@@ -2615,9 +2592,9 @@ dependencies = [
 
 [[package]]
 name = "serde_json"
-version = "1.0.51"
+version = "1.0.52"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "da07b57ee2623368351e9a0488bb0b261322a15a6e0ae53e243cbdc0f4208da9"
+checksum = "a7894c8ed05b7a3a279aeb79025fdec1d3158080b75b98a08faf2806bb799edd"
 dependencies = [
  "indexmap",
  "itoa",
@@ -2773,9 +2750,9 @@ dependencies = [
 
 [[package]]
 name = "syn"
-version = "1.0.18"
+version = "1.0.19"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "410a7488c0a728c7ceb4ad59b9567eb4053d02e8cc7f5c0e0eeeb39518369213"
+checksum = "e8e5aa70697bb26ee62214ae3288465ecec0000f05182f039b477001f08f5ae7"
 dependencies = [
  "proc-macro2",
  "quote",
@@ -2902,9 +2879,9 @@ dependencies = [
 
 [[package]]
 name = "tokio"
-version = "0.2.19"
+version = "0.2.20"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "7d9c43f1bb96970e153bcbae39a65e249ccb942bd9d36dbdf086024920417c9c"
+checksum = "05c1d570eb1a36f0345a5ce9c6c6e665b70b73d11236912c0b477616aeec47b1"
 dependencies = [
  "bytes 0.5.4",
  "fnv",
@@ -3113,9 +3090,9 @@ checksum = "826e7639553986605ec5979c7dd957c7895e93eabed50ab2ffa7f6128a75097c"
 
 [[package]]
 name = "untrusted"
-version = "0.7.0"
+version = "0.7.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "60369ef7a31de49bcb3f6ca728d4ba7300d9a1658f94c727d4cab8c8d9f4aece"
+checksum = "a156c684c91ea7d62626509bce3cb4e1d9ed5c4d978f7b4352658f96a4c26b4a"
 
 [[package]]
 name = "ureq"
@@ -3123,7 +3100,7 @@ version = "0.12.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "cd754afd5f60388b4188210c3795392c5f2fd69a1cc947ec4505dbfee955b902"
 dependencies = [
- "base64 0.12.0",
+ "base64 0.12.1",
  "chunked_transfer",
  "lazy_static",
  "qstring",
@@ -3200,9 +3177,9 @@ checksum = "3fc439f2794e98976c88a2a2dafce96b930fe8010b0a256b3c2199a773933168"
 
 [[package]]
 name = "vec_map"
-version = "0.8.1"
+version = "0.8.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "05c78687fb1a80548ae3250346c3db86a80a7cdd77bda190189f2d0a0987c81a"
+checksum = "f1bddf1187be692e79c5ffeab891132dfb0f236ed36a43c7ed39f1165ee20191"
 
 [[package]]
 name = "vergen"
@@ -3261,9 +3238,9 @@ checksum = "cccddf32554fecc6acb585f82a32a72e28b48f8c4c1883ddfeeeaa96f7d8e519"
 
 [[package]]
 name = "wasm-bindgen"
-version = "0.2.60"
+version = "0.2.62"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "2cc57ce05287f8376e998cbddfb4c8cb43b84a7ec55cf4551d7c00eef317a47f"
+checksum = "e3c7d40d09cdbf0f4895ae58cf57d92e1e57a9dd8ed2e8390514b54a47cc5551"
 dependencies = [
  "cfg-if",
  "serde",
@@ -3273,9 +3250,9 @@ dependencies = [
 
 [[package]]
 name = "wasm-bindgen-backend"
-version = "0.2.60"
+version = "0.2.62"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "d967d37bf6c16cca2973ca3af071d0a2523392e4a594548155d89a678f4237cd"
+checksum = "c3972e137ebf830900db522d6c8fd74d1900dcfc733462e9a12e942b00b4ac94"
 dependencies = [
  "bumpalo",
  "lazy_static",
@@ -3288,9 +3265,9 @@ dependencies = [
 
 [[package]]
 name = "wasm-bindgen-futures"
-version = "0.4.10"
+version = "0.4.12"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "7add542ea1ac7fdaa9dc25e031a6af33b7d63376292bd24140c637d00d1c312a"
+checksum = "8a369c5e1dfb7569e14d62af4da642a3cbc2f9a3652fe586e26ac22222aa4b04"
 dependencies = [
  "cfg-if",
  "js-sys",
@@ -3300,9 +3277,9 @@ dependencies = [
 
 [[package]]
 name = "wasm-bindgen-macro"
-version = "0.2.60"
+version = "0.2.62"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "8bd151b63e1ea881bb742cd20e1d6127cef28399558f3b5d415289bc41eee3a4"
+checksum = "2cd85aa2c579e8892442954685f0d801f9129de24fa2136b2c6a539c76b65776"
 dependencies = [
  "quote",
  "wasm-bindgen-macro-support",
@@ -3310,9 +3287,9 @@ dependencies = [
 
 [[package]]
 name = "wasm-bindgen-macro-support"
-version = "0.2.60"
+version = "0.2.62"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "d68a5b36eef1be7868f668632863292e37739656a80fc4b9acec7b0bd35a4931"
+checksum = "8eb197bd3a47553334907ffd2f16507b4f4f01bbec3ac921a7719e0decdfe72a"
 dependencies = [
  "proc-macro2",
  "quote",
@@ -3323,15 +3300,15 @@ dependencies = [
 
 [[package]]
 name = "wasm-bindgen-shared"
-version = "0.2.60"
+version = "0.2.62"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "daf76fe7d25ac79748a37538b7daeed1c7a6867c92d3245c12c6222e4a20d639"
+checksum = "a91c2916119c17a8e316507afaaa2dd94b47646048014bbdf6bef098c1bb58ad"
 
 [[package]]
 name = "web-sys"
-version = "0.3.37"
+version = "0.3.39"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "2d6f51648d8c56c366144378a33290049eafdd784071077f6fe37dae64c1c4cb"
+checksum = "8bc359e5dd3b46cb9687a051d50a2fdd228e4ba7cf6fcf861a5365c3d671a642"
 dependencies = [
  "js-sys",
  "wasm-bindgen",

meilisearch-core/Cargo.toml

@@ -11,8 +11,10 @@ bincode = "1.2.1"
 byteorder = "1.3.4"
 chrono = { version = "0.4.11", features = ["serde"] }
 compact_arena = "0.4.0"
+cow-utils = "0.1.2"
 crossbeam-channel = "0.4.2"
 deunicode = "1.1.0"
+either = "1.5.3"
 env_logger = "0.7.1"
 fst = { version = "0.3.5", default-features = false }
 hashbrown = { version = "0.7.1", features = ["serde"] }

meilisearch-core/src/error.rs

@@ -28,7 +28,8 @@ pub enum Error {
     Serializer(SerializerError),
     Deserializer(DeserializerError),
     UnsupportedOperation(UnsupportedOperation),
-    FilterParseError(PestError<Rule>)
+    FilterParseError(PestError<Rule>),
+    FacetError(FacetError),
 }
 
 impl From<io::Error> for Error {
@@ -59,6 +60,12 @@ impl From<PestError<Rule>> for Error {
     }
 }
 
+impl From<FacetError> for Error {
+    fn from(error: FacetError) -> Error {
+        Error::FacetError(error)
+    }
+}
+
 impl From<meilisearch_schema::Error> for Error {
     fn from(error: meilisearch_schema::Error) -> Error {
         Error::Schema(error)
@@ -127,6 +134,7 @@ impl fmt::Display for Error {
             Deserializer(e) => write!(f, "deserializer error; {}", e),
             UnsupportedOperation(op) => write!(f, "unsupported operation; {}", op),
             FilterParseError(e) => write!(f, "error parsing filter; {}", e),
+            FacetError(e) => write!(f, "error processing facet filter: {}", e),
         }
     }
 }
@@ -156,3 +164,40 @@ impl fmt::Display for UnsupportedOperation {
         }
     }
 }
+
+#[derive(Debug)]
+pub enum FacetError {
+    EmptyArray,
+    ParsingError(String),
+    UnexpectedToken { expected: &'static [&'static str], found: String },
+    InvalidFormat(String),
+    AttributeNotFound(String),
+    AttributeNotSet { expected: Vec<String>, found: String },
+    InvalidDocumentAttribute(String),
+}
+
+impl FacetError {
+    pub fn unexpected_token(expected: &'static [&'static str], found: impl ToString) -> FacetError {
+        FacetError::UnexpectedToken{ expected, found: found.to_string() }
+    }
+
+    pub fn attribute_not_set(expected: Vec<String>, found: impl ToString) -> FacetError {
+        FacetError::AttributeNotSet{ expected, found: found.to_string() }
+    }
+}
+
+impl fmt::Display for FacetError {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        use FacetError::*;
+
+        match self {
+            EmptyArray => write!(f, "empty array in facet filter is unspecified behavior"),
+            ParsingError(msg) => write!(f, "parsing error: {}", msg),
+            UnexpectedToken { expected, found } => write!(f, "unexpected token {}, expected {}", found, expected.join("or")),
+            InvalidFormat(found) => write!(f, "invalid facet: {}, facets should be \"facetName:facetValue\"", found),
+            AttributeNotFound(attr) => write!(f, "unknown {:?} attribute", attr),
+            AttributeNotSet { found, expected } => write!(f, "`{}` is not set as a faceted attribute. available facet attributes: {}", found, expected.join(", ")),
+            InvalidDocumentAttribute(attr) => write!(f, "invalid document attribute {}, accepted types: string and [string]", attr),
+        }
+    }
+}

meilisearch-core/src/facets.rs

@@ -0,0 +1,353 @@
+use std::borrow::Cow;
+use std::collections::HashMap;
+use std::hash::Hash;
+use std::ops::Deref;
+
+use cow_utils::CowUtils;
+use either::Either;
+use heed::types::{Str, OwnedType};
+use indexmap::IndexMap;
+use serde_json::Value;
+
+use meilisearch_schema::{FieldId, Schema};
+use meilisearch_types::DocumentId;
+
+use crate::database::MainT;
+use crate::error::{FacetError, Error};
+use crate::store::BEU16;
+
+/// Data structure used to represent a boolean expression in the form of nested arrays.
+/// Values in the outer array are and-ed together, values in the inner arrays are or-ed together.
+#[derive(Debug, PartialEq)]
+pub struct FacetFilter(Vec<Either<Vec<FacetKey>, FacetKey>>);
+
+impl Deref for FacetFilter {
+    type Target = Vec<Either<Vec<FacetKey>, FacetKey>>;
+
+    fn deref(&self) -> &Self::Target {
+        &self.0
+    }
+}
+
+impl FacetFilter {
+    pub fn from_str(
+        s: &str,
+        schema: &Schema,
+        attributes_for_faceting: &[FieldId],
+    ) -> Result<Self, FacetError> {
+
+        let parsed = serde_json::from_str::<Value>(s).map_err(|e| FacetError::ParsingError(e.to_string()))?;
+        let mut filter = Vec::new();
+        match parsed {
+            Value::Array(and_exprs) => {
+                if and_exprs.is_empty() {
+                    return Err(FacetError::EmptyArray);
+                }
+                for expr in and_exprs {
+                    match expr {
+                        Value::String(s) => {
+                            let key = FacetKey::from_str( &s, schema, attributes_for_faceting)?;
+                            filter.push(Either::Right(key));
+                        }
+                        Value::Array(or_exprs) => {
+                            if or_exprs.is_empty() {
+                                return Err(FacetError::EmptyArray);
+                            }
+                            let mut inner = Vec::new();
+                            for expr in or_exprs {
+                                match expr {
+                                    Value::String(s) => {
+                                        let key = FacetKey::from_str( &s, schema, attributes_for_faceting)?;
+                                        inner.push(key);
+                                    }
+                                    bad_value => return Err(FacetError::unexpected_token(&["String"], bad_value)),
+                                }
+                            }
+                            filter.push(Either::Left(inner));
+                        }
+                        bad_value => return Err(FacetError::unexpected_token(&["Array", "String"], bad_value)),
+                    }
+                }
+                return Ok(Self(filter));
+            }
+            bad_value => Err(FacetError::unexpected_token(&["String"], bad_value)),
+        }
+    }
+}
+
+#[derive(Debug, Eq, PartialEq, Hash)]
+#[repr(C)]
+pub struct FacetKey(FieldId, String);
+
+impl FacetKey {
+    pub fn new(field_id: FieldId, value: String) -> Self {
+        let value = match value.cow_to_lowercase() {
+                Cow::Borrowed(_) => value,
+                Cow::Owned(s) => s,
+        };
+        Self(field_id, value)
+    }
+
+    pub fn key(&self) -> FieldId {
+        self.0
+    }
+
+    pub fn value(&self) -> &str {
+        &self.1
+    }
+
+    // TODO improve parser
+    fn from_str(
+        s: &str,
+        schema: &Schema,
+        attributes_for_faceting: &[FieldId],
+    ) -> Result<Self, FacetError> {
+        let mut split = s.splitn(2, ':');
+        let key = split
+            .next()
+            .ok_or_else(|| FacetError::InvalidFormat(s.to_string()))?
+            .trim();
+        let field_id = schema
+            .id(key)
+            .ok_or_else(|| FacetError::AttributeNotFound(key.to_string()))?;
+
+        if !attributes_for_faceting.contains(&field_id) {
+            return Err(FacetError::attribute_not_set(
+                    attributes_for_faceting
+                    .iter()
+                    .filter_map(|&id| schema.name(id))
+                    .map(str::to_string)
+                    .collect::<Vec<_>>(),
+                    key))
+        }
+        let value = split
+            .next()
+            .ok_or_else(|| FacetError::InvalidFormat(s.to_string()))?
+            .trim();
+        // unquoting the string if need be:
+        let mut indices = value.char_indices();
+        let value =  match (indices.next(), indices.last()) {
+            (Some((s, '\'')), Some((e, '\''))) |
+            (Some((s, '\"')), Some((e, '\"'))) => value[s + 1..e].to_string(),
+            _ => value.to_string(),
+        };
+        Ok(Self::new(field_id, value))
+    }
+}
+
+impl<'a> heed::BytesEncode<'a> for FacetKey {
+    type EItem = FacetKey;
+
+    fn bytes_encode(item: &'a Self::EItem) -> Option<Cow<'a, [u8]>> {
+        let mut buffer = Vec::with_capacity(2 + item.1.len());
+        let id = BEU16::new(item.key().into());
+        let id_bytes = OwnedType::bytes_encode(&id)?;
+        let value_bytes = Str::bytes_encode(item.value())?;
+        buffer.extend_from_slice(id_bytes.as_ref());
+        buffer.extend_from_slice(value_bytes.as_ref());
+        Some(Cow::Owned(buffer))
+    }
+}
+
+impl<'a> heed::BytesDecode<'a> for FacetKey {
+    type DItem = FacetKey;
+
+    fn bytes_decode(bytes: &'a [u8]) -> Option<Self::DItem> {
+        let (id_bytes, value_bytes) = bytes.split_at(2);
+        let id = OwnedType::<BEU16>::bytes_decode(id_bytes)?;
+        let id = id.get().into();
+        let string = Str::bytes_decode(&value_bytes)?;
+        Some(FacetKey(id, string.to_string()))
+    }
+}
+
+pub fn add_to_facet_map(
+    facet_map: &mut HashMap<FacetKey, Vec<DocumentId>>,
+    field_id: FieldId,
+    value: Value,
+    document_id: DocumentId,
+) -> Result<(), FacetError> {
+    let value = match value {
+        Value::String(s) => s,
+        // ignore null
+        Value::Null => return Ok(()),
+        value => return Err(FacetError::InvalidDocumentAttribute(value.to_string())),
+    };
+    let key = FacetKey::new(field_id, value);
+    facet_map.entry(key).or_insert_with(Vec::new).push(document_id);
+    Ok(())
+}
+
+pub fn facet_map_from_docids(
+    rtxn: &heed::RoTxn<MainT>,
+    index: &crate::Index,
+    document_ids: &[DocumentId],
+    attributes_for_facetting: &[FieldId],
+) -> Result<HashMap<FacetKey, Vec<DocumentId>>, Error> {
+    let mut facet_map = HashMap::new();
+    for document_id in document_ids {
+        for result in index
+            .documents_fields
+            .document_fields(rtxn, *document_id)?
+        {
+            let (field_id, bytes) = result?;
+            if attributes_for_facetting.contains(&field_id) {
+                match serde_json::from_slice(bytes)? {
+                    Value::Array(values) => {
+                        for v in values {
+                            add_to_facet_map(&mut facet_map, field_id, v, *document_id)?;
+                        }
+                    }
+                    v => add_to_facet_map(&mut facet_map, field_id, v, *document_id)?,
+                };
+            }
+        }
+    }
+    Ok(facet_map)
+}
+
+pub fn facet_map_from_docs(
+    schema: &Schema,
+    documents: &HashMap<DocumentId, IndexMap<String, Value>>,
+    attributes_for_facetting: &[FieldId],
+) -> Result<HashMap<FacetKey, Vec<DocumentId>>, Error> {
+    let mut facet_map = HashMap::new();
+    let attributes_for_facetting = attributes_for_facetting
+        .iter()
+        .filter_map(|&id| schema.name(id).map(|name| (id, name)))
+        .collect::<Vec<_>>();
+
+    for (id, document) in documents {
+        for (field_id, name) in &attributes_for_facetting {
+            if let Some(value) = document.get(*name) {
+                match value {
+                    Value::Array(values) => {
+                        for v in values {
+                            add_to_facet_map(&mut facet_map, *field_id, v.clone(), *id)?;
+                        }
+                    }
+                    v => add_to_facet_map(&mut facet_map, *field_id, v.clone(), *id)?,
+                }
+            }
+        }
+    }
+    Ok(facet_map)
+}
+
+#[cfg(test)]
+mod test {
+    use super::*;
+    use meilisearch_schema::Schema;
+
+    #[test]
+    fn test_facet_key() {
+        let mut schema = Schema::new();
+        let id = schema.insert_and_index("hello").unwrap();
+        let facet_list = [schema.id("hello").unwrap()];
+        assert_eq!(
+            FacetKey::from_str("hello:12", &schema, &facet_list).unwrap(),
+            FacetKey::new(id, "12".to_string())
+        );
+        assert_eq!(
+            FacetKey::from_str("hello:\"foo bar\"", &schema, &facet_list).unwrap(),
+            FacetKey::new(id, "foo bar".to_string())
+        );
+        assert_eq!(
+            FacetKey::from_str("hello:'foo bar'", &schema, &facet_list).unwrap(),
+            FacetKey::new(id, "foo bar".to_string())
+        );
+        // weird case
+        assert_eq!(
+            FacetKey::from_str("hello:blabla:machin", &schema, &facet_list).unwrap(),
+            FacetKey::new(id, "blabla:machin".to_string())
+        );
+
+        assert_eq!(
+            FacetKey::from_str("hello:\"\"", &schema, &facet_list).unwrap(),
+            FacetKey::new(id, "".to_string())
+        );
+
+        assert_eq!(
+            FacetKey::from_str("hello:'", &schema, &facet_list).unwrap(),
+            FacetKey::new(id, "'".to_string())
+        );
+        assert_eq!(
+            FacetKey::from_str("hello:''", &schema, &facet_list).unwrap(),
+            FacetKey::new(id, "".to_string())
+        );
+        assert!(FacetKey::from_str("hello", &schema, &facet_list).is_err());
+        assert!(FacetKey::from_str("toto:12", &schema, &facet_list).is_err());
+    }
+
+    #[test]
+    fn test_parse_facet_array() {
+        use either::Either::{Left, Right};
+        let mut schema = Schema::new();
+        let _id = schema.insert_and_index("hello").unwrap();
+        let facet_list = [schema.id("hello").unwrap()];
+        assert_eq!(
+            FacetFilter::from_str("[[\"hello:12\"]]", &schema, &facet_list).unwrap(),
+            FacetFilter(vec![Left(vec![FacetKey(FieldId(0), "12".to_string())])])
+        );
+        assert_eq!(
+            FacetFilter::from_str("[\"hello:12\"]", &schema, &facet_list).unwrap(),
+            FacetFilter(vec![Right(FacetKey(FieldId(0), "12".to_string()))])
+        );
+        assert_eq!(
+            FacetFilter::from_str("[\"hello:12\", \"hello:13\"]", &schema, &facet_list).unwrap(),
+            FacetFilter(vec![
+                Right(FacetKey(FieldId(0), "12".to_string())),
+                Right(FacetKey(FieldId(0), "13".to_string()))
+            ])
+        );
+        assert_eq!(
+            FacetFilter::from_str("[[\"hello:12\", \"hello:13\"]]", &schema, &facet_list).unwrap(),
+            FacetFilter(vec![Left(vec![
+                FacetKey(FieldId(0), "12".to_string()),
+                FacetKey(FieldId(0), "13".to_string())
+            ])])
+        );
+        assert_eq!(
+            FacetFilter::from_str(
+                "[[\"hello:12\", \"hello:13\"], \"hello:14\"]",
+                &schema,
+                &facet_list
+            )
+            .unwrap(),
+            FacetFilter(vec![
+                Left(vec![
+                    FacetKey(FieldId(0), "12".to_string()),
+                    FacetKey(FieldId(0), "13".to_string())
+                ]),
+                Right(FacetKey(FieldId(0), "14".to_string()))
+            ])
+        );
+
+        // invalid array depths
+        assert!(FacetFilter::from_str(
+            "[[[\"hello:12\", \"hello:13\"], \"hello:14\"]]",
+            &schema,
+            &facet_list
+        )
+        .is_err());
+        assert!(FacetFilter::from_str(
+            "[[[\"hello:12\", \"hello:13\"]], \"hello:14\"]]",
+            &schema,
+            &facet_list
+        )
+        .is_err());
+        assert!(FacetFilter::from_str("\"hello:14\"", &schema, &facet_list).is_err());
+
+        // unexisting key
+        assert!(FacetFilter::from_str("[\"foo:12\"]", &schema, &facet_list).is_err());
+
+        // invalid facet key
+        assert!(FacetFilter::from_str("[\"foo=12\"]", &schema, &facet_list).is_err());
+        assert!(FacetFilter::from_str("[\"foo12\"]", &schema, &facet_list).is_err());
+        assert!(FacetFilter::from_str("[\"\"]", &schema, &facet_list).is_err());
+
+        // empty array error
+        assert!(FacetFilter::from_str("[]", &schema, &facet_list).is_err());
+        assert!(FacetFilter::from_str("[\"hello:12\", []]", &schema, &facet_list).is_err());
+    }
+}

meilisearch-core/src/lib.rs

@@ -19,14 +19,15 @@ mod ranked_map;
 mod raw_document;
 mod reordered_attrs;
 mod update;
-pub mod settings;
 pub mod criterion;
+pub mod facets;
 pub mod raw_indexer;
+pub mod settings;
 pub mod serde;
 pub mod store;
 
 pub use self::database::{BoxUpdateFn, Database, DatabaseOptions, MainT, UpdateT};
-pub use self::error::{Error, HeedError, FstError, MResult, pest_error};
+pub use self::error::{Error, HeedError, FstError, MResult, pest_error, FacetError};
 pub use self::filters::Filter;
 pub use self::number::{Number, ParseNumberError};
 pub use self::ranked_map::RankedMap;

meilisearch-core/src/store/cow_set.rs

@@ -0,0 +1,32 @@
+use std::borrow::Cow;
+
+use heed::{types::CowSlice, BytesEncode, BytesDecode};
+use sdset::{Set, SetBuf};
+use zerocopy::{AsBytes, FromBytes};
+
+pub struct CowSet<T>(std::marker::PhantomData<T>);
+
+impl<'a, T: 'a> BytesEncode<'a> for CowSet<T>
+where
+    T: AsBytes,
+{
+    type EItem = Set<T>;
+
+    fn bytes_encode(item: &'a Self::EItem) -> Option<Cow<[u8]>> {
+        CowSlice::bytes_encode(item.as_slice())
+    }
+}
+
+impl<'a, T: 'a> BytesDecode<'a> for CowSet<T>
+where
+    T: FromBytes + Copy,
+{
+    type DItem = Cow<'a, Set<T>>;
+
+    fn bytes_decode(bytes: &'a [u8]) -> Option<Self::DItem> {
+        match CowSlice::<T>::bytes_decode(bytes)? {
+            Cow::Owned(vec) => Some(Cow::Owned(SetBuf::new_unchecked(vec))),
+            Cow::Borrowed(slice) => Some(Cow::Borrowed(Set::new_unchecked(slice))),
+        }
+    }
+}

meilisearch-core/src/store/facets.rs

@@ -0,0 +1,53 @@
+use std::borrow::Cow;
+use std::collections::HashMap;
+
+use heed::{RwTxn, RoTxn, Result as ZResult};
+use sdset::{SetBuf, Set, SetOperation};
+
+use meilisearch_types::DocumentId;
+
+use crate::database::MainT;
+use crate::facets::FacetKey;
+use super::cow_set::CowSet;
+
+/// contains facet info
+#[derive(Clone, Copy)]
+pub struct Facets {
+    pub(crate) facets: heed::Database<FacetKey, CowSet<DocumentId>>,
+}
+
+impl Facets {
+    // we use sdset::SetBuf to ensure the docids are sorted.
+    pub fn put_facet_document_ids(&self, writer: &mut RwTxn<MainT>, facet_key: FacetKey, doc_ids: &Set<DocumentId>) -> ZResult<()> {
+        self.facets.put(writer, &facet_key, doc_ids)
+    }
+
+    pub fn facet_document_ids<'txn>(&self, reader: &'txn RoTxn<MainT>, facet_key: &FacetKey) -> ZResult<Option<Cow<'txn, Set<DocumentId>>>> {
+        self.facets.get(reader, &facet_key)
+    }
+
+    /// updates the facets  store, revmoving the documents from the facets provided in the
+    /// `facet_map` argument
+    pub fn remove(&self, writer: &mut RwTxn<MainT>, facet_map: HashMap<FacetKey, Vec<DocumentId>>) -> ZResult<()> {
+        for (key, document_ids) in facet_map {
+            if let Some(old) = self.facets.get(writer, &key)? {
+                let to_remove = SetBuf::from_dirty(document_ids);
+                let new = sdset::duo::OpBuilder::new(old.as_ref(), to_remove.as_set()).difference().into_set_buf();
+                self.facets.put(writer, &key, new.as_set())?;
+            }
+        }
+        Ok(())
+    }
+
+    pub fn add(&self, writer: &mut RwTxn<MainT>, facet_map: HashMap<FacetKey, Vec<DocumentId>>) -> ZResult<()> {
+        for (key, document_ids) in facet_map {
+            let set = SetBuf::from_dirty(document_ids);
+            self.put_facet_document_ids(writer, key, set.as_set())?;
+        }
+        Ok(())
+    }
+
+    pub fn clear(self, writer: &mut heed::RwTxn<MainT>) -> ZResult<()> {
+        self.facets.clear(writer)
+    }
+}

meilisearch-core/src/store/main.rs

@@ -4,13 +4,16 @@ use std::collections::HashMap;
 use chrono::{DateTime, Utc};
 use heed::types::{ByteSlice, OwnedType, SerdeBincode, Str};
 use heed::Result as ZResult;
-use meilisearch_schema::Schema;
+use meilisearch_schema::{FieldId, Schema};
+use sdset::Set;
 
 use crate::database::MainT;
 use crate::RankedMap;
 use crate::settings::RankingRule;
+use super::cow_set::CowSet;
 
 const CREATED_AT_KEY: &str = "created-at";
+const ATTRIBUTES_FOR_FACETING: &str = "attributes-for-faceting";
 const RANKING_RULES_KEY: &str = "ranking-rules";
 const DISTINCT_ATTRIBUTE_KEY: &str = "distinct-attribute";
 const STOP_WORDS_KEY: &str = "stop-words";
@@ -188,6 +191,18 @@ impl Main {
         }
     }
 
+    pub fn attributes_for_faceting<'txn>(&self, reader: &'txn heed::RoTxn<MainT>) -> ZResult<Option<Cow<'txn, Set<FieldId>>>> {
+        self.main.get::<_, Str, CowSet<FieldId>>(reader, ATTRIBUTES_FOR_FACETING)
+    }
+
+    pub fn put_attributes_for_faceting(self, writer: &mut heed::RwTxn<MainT>, attributes: &Set<FieldId>) -> ZResult<()> {
+        self.main.put::<_, Str, CowSet<FieldId>>(writer, ATTRIBUTES_FOR_FACETING, attributes)
+    }
+
+    pub fn delete_attributes_for_faceting(self, writer: &mut heed::RwTxn<MainT>) -> ZResult<bool> {
+        self.main.delete::<_, Str>(writer, ATTRIBUTES_FOR_FACETING)
+    }
+
     pub fn ranking_rules(&self, reader: &heed::RoTxn<MainT>) -> ZResult<Option<Vec<RankingRule>>> {
         self.main.get::<_, Str, SerdeBincode<Vec<RankingRule>>>(reader, RANKING_RULES_KEY)
     }

meilisearch-core/src/store/mod.rs

@@ -1,3 +1,4 @@
+mod cow_set;
 mod docs_words;
 mod prefix_documents_cache;
 mod prefix_postings_lists_cache;
@@ -8,8 +9,10 @@ mod postings_lists;
 mod synonyms;
 mod updates;
 mod updates_results;
+mod facets;
 
 pub use self::docs_words::DocsWords;
+pub use self::facets::Facets;
 pub use self::prefix_documents_cache::PrefixDocumentsCache;
 pub use self::prefix_postings_lists_cache::PrefixPostingsListsCache;
 pub use self::documents_fields::{DocumentFieldsIter, DocumentsFields};
@@ -42,7 +45,7 @@ use crate::settings::SettingsUpdate;
 use crate::{query_builder::QueryBuilder, update, DocIndex, DocumentId, Error, MResult};
 
 type BEU64 = zerocopy::U64<byteorder::BigEndian>;
-type BEU16 = zerocopy::U16<byteorder::BigEndian>;
+pub type BEU16 = zerocopy::U16<byteorder::BigEndian>;
 
 #[derive(Debug, Copy, Clone, AsBytes, FromBytes)]
 #[repr(C)]
@@ -197,12 +200,17 @@ fn updates_results_name(name: &str) -> String {
     format!("store-{}-updates-results", name)
 }
 
+fn facets_name(name: &str) -> String {
+    format!("store-{}-facets", name)
+}
+
 #[derive(Clone)]
 pub struct Index {
     pub main: Main,
     pub postings_lists: PostingsLists,
     pub documents_fields: DocumentsFields,
     pub documents_fields_counts: DocumentsFieldsCounts,
+    pub facets: Facets,
     pub synonyms: Synonyms,
     pub docs_words: DocsWords,
     pub prefix_documents_cache: PrefixDocumentsCache,
@@ -352,29 +360,14 @@ impl Index {
     }
 
     pub fn query_builder(&self) -> QueryBuilder {
-        QueryBuilder::new(
+        QueryBuilder::new(self)
-            self.main,
-            self.postings_lists,
-            self.documents_fields_counts,
-            self.synonyms,
-            self.prefix_documents_cache,
-            self.prefix_postings_lists_cache,
-        )
     }
 
-    pub fn query_builder_with_criteria<'c, 'f, 'd>(
+    pub fn query_builder_with_criteria<'c, 'f, 'd, 'fa, 'i>(
-        &self,
+        &'i self,
         criteria: Criteria<'c>,
-    ) -> QueryBuilder<'c, 'f, 'd> {
+    ) -> QueryBuilder<'c, 'f, 'd, 'fa, 'i> {
-        QueryBuilder::with_criteria(
+        QueryBuilder::with_criteria(self, criteria)
-            self.main,
-            self.postings_lists,
-            self.documents_fields_counts,
-            self.synonyms,
-            self.prefix_documents_cache,
-            self.prefix_postings_lists_cache,
-            criteria,
-        )
     }
 }
 
@@ -395,12 +388,14 @@ pub fn create(
     let prefix_postings_lists_cache_name = prefix_postings_lists_cache_name(name);
     let updates_name = updates_name(name);
     let updates_results_name = updates_results_name(name);
+    let facets_name = facets_name(name);
 
     // open all the stores
     let main = env.create_poly_database(Some(&main_name))?;
     let postings_lists = env.create_database(Some(&postings_lists_name))?;
     let documents_fields = env.create_database(Some(&documents_fields_name))?;
     let documents_fields_counts = env.create_database(Some(&documents_fields_counts_name))?;
+    let facets = env.create_database(Some(&facets_name))?;
     let synonyms = env.create_database(Some(&synonyms_name))?;
     let docs_words = env.create_database(Some(&docs_words_name))?;
     let prefix_documents_cache = env.create_database(Some(&prefix_documents_cache_name))?;
@@ -417,6 +412,8 @@ pub fn create(
         docs_words: DocsWords { docs_words },
         prefix_postings_lists_cache: PrefixPostingsListsCache { prefix_postings_lists_cache },
         prefix_documents_cache: PrefixDocumentsCache { prefix_documents_cache },
+        facets: Facets { facets },
+
         updates: Updates { updates },
         updates_results: UpdatesResults { updates_results },
         updates_notifier,
@@ -437,6 +434,7 @@ pub fn open(
     let synonyms_name = synonyms_name(name);
     let docs_words_name = docs_words_name(name);
     let prefix_documents_cache_name = prefix_documents_cache_name(name);
+    let facets_name = facets_name(name);
     let prefix_postings_lists_cache_name = prefix_postings_lists_cache_name(name);
     let updates_name = updates_name(name);
     let updates_results_name = updates_results_name(name);
@@ -470,6 +468,10 @@ pub fn open(
         Some(prefix_documents_cache) => prefix_documents_cache,
         None => return Ok(None),
     };
+    let facets = match env.open_database(Some(&facets_name))? {
+        Some(facets) => facets,
+        None => return Ok(None),
+    };
     let prefix_postings_lists_cache = match env.open_database(Some(&prefix_postings_lists_cache_name))? {
         Some(prefix_postings_lists_cache) => prefix_postings_lists_cache,
         None => return Ok(None),
@@ -491,6 +493,7 @@ pub fn open(
         synonyms: Synonyms { synonyms },
         docs_words: DocsWords { docs_words },
         prefix_documents_cache: PrefixDocumentsCache { prefix_documents_cache },
+        facets: Facets { facets },
         prefix_postings_lists_cache: PrefixPostingsListsCache { prefix_postings_lists_cache },
         updates: Updates { updates },
         updates_results: UpdatesResults { updates_results },

meilisearch-http/src/error.rs

@@ -23,6 +23,7 @@ pub enum ResponseError {
     FilterParsing(String),
     RetrieveDocument(u64, String),
     SearchDocuments(String),
+    FacetExpression(String),
 }
 
 impl ResponseError {
@@ -106,6 +107,7 @@ impl fmt::Display for ResponseError {
             Self::OpenIndex(err) => write!(f, "Impossible to open index; {}", err),
             Self::RetrieveDocument(id, err) => write!(f, "impossible to retrieve the document with id: {}; {}", id, err),
             Self::SearchDocuments(err) => write!(f, "impossible to search documents; {}", err),
+            Self::FacetExpression(e) => write!(f, "error parsing facet filter expression: {}", e),
         }
     }
 }
@@ -125,6 +127,7 @@ impl aweb::error::ResponseError for ResponseError {
             | Self::InvalidIndexUid
             | Self::OpenIndex(_)
             | Self::RetrieveDocument(_, _)
+            | Self::FacetExpression(_)
             | Self::SearchDocuments(_)
             | Self::FilterParsing(_) => StatusCode::BAD_REQUEST,
             Self::DocumentNotFound(_)
@@ -151,6 +154,12 @@ impl From<meilisearch_core::FstError> for ResponseError {
     }
 }
 
+impl From<meilisearch_core::FacetError> for ResponseError {
+    fn from(error: meilisearch_core::FacetError) -> ResponseError {
+        ResponseError::FacetExpression(error.to_string())
+    }
+}
+
 impl From<meilisearch_core::Error> for ResponseError {
     fn from(err: meilisearch_core::Error) -> ResponseError {
         use meilisearch_core::pest_error::LineColLocation::*;
@@ -164,6 +173,7 @@ impl From<meilisearch_core::Error> for ResponseError {
 
                 ResponseError::FilterParsing(message)
             },
+            meilisearch_core::Error::FacetError(e) => ResponseError::FacetExpression(e.to_string()),
             _ => ResponseError::Internal(err.to_string()),
         }
     }

meilisearch-schema/src/lib.rs

@@ -36,7 +36,10 @@ impl Into<u16> for IndexedPos {
     }
 }
 
-#[derive(Serialize, Deserialize, Debug, Copy, Clone, Default, PartialOrd, Ord, PartialEq, Eq, Hash)]
+#[derive(Debug, Copy, Clone, Default, PartialOrd, Ord, PartialEq, Eq, Hash)]
+#[derive(Serialize, Deserialize)]
+#[derive(AsBytes, FromBytes)]
+#[repr(C)]
 pub struct FieldId(pub u16);
 
 impl FieldId {
@@ -63,8 +66,8 @@ impl From<u16> for FieldId {
     }
 }
 
-impl Into<u16> for FieldId {
+impl From<FieldId> for u16 {
-    fn into(self) -> u16 {
+    fn from(other: FieldId) -> u16 {
-        self.0
+        other.0
     }
 }