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1 | package hcl | |
2 | ||
3 | import ( | |
4 | "fmt" | |
5 | ) | |
6 | ||
7 | // MergeFiles combines the given files to produce a single body that contains | |
8 | // configuration from all of the given files. | |
9 | // | |
10 | // The ordering of the given files decides the order in which contained | |
11 | // elements will be returned. If any top-level attributes are defined with | |
12 | // the same name across multiple files, a diagnostic will be produced from | |
13 | // the Content and PartialContent methods describing this error in a | |
14 | // user-friendly way. | |
15 | func MergeFiles(files []*File) Body { | |
16 | var bodies []Body | |
17 | for _, file := range files { | |
18 | bodies = append(bodies, file.Body) | |
19 | } | |
20 | return MergeBodies(bodies) | |
21 | } | |
22 | ||
23 | // MergeBodies is like MergeFiles except it deals directly with bodies, rather | |
24 | // than with entire files. | |
25 | func MergeBodies(bodies []Body) Body { | |
26 | if len(bodies) == 0 { | |
27 | // Swap out for our singleton empty body, to reduce the number of | |
28 | // empty slices we have hanging around. | |
29 | return emptyBody | |
30 | } | |
31 | ||
32 | // If any of the given bodies are already merged bodies, we'll unpack | |
33 | // to flatten to a single mergedBodies, since that's conceptually simpler. | |
34 | // This also, as a side-effect, eliminates any empty bodies, since | |
35 | // empties are merged bodies with no inner bodies. | |
36 | var newLen int | |
37 | var flatten bool | |
38 | for _, body := range bodies { | |
39 | if children, merged := body.(mergedBodies); merged { | |
40 | newLen += len(children) | |
41 | flatten = true | |
42 | } else { | |
43 | newLen++ | |
44 | } | |
45 | } | |
46 | ||
47 | if !flatten { // not just newLen == len, because we might have mergedBodies with single bodies inside | |
48 | return mergedBodies(bodies) | |
49 | } | |
50 | ||
51 | if newLen == 0 { | |
52 | // Don't allocate a new empty when we already have one | |
53 | return emptyBody | |
54 | } | |
55 | ||
56 | new := make([]Body, 0, newLen) | |
57 | for _, body := range bodies { | |
58 | if children, merged := body.(mergedBodies); merged { | |
59 | new = append(new, children...) | |
60 | } else { | |
61 | new = append(new, body) | |
62 | } | |
63 | } | |
64 | return mergedBodies(new) | |
65 | } | |
66 | ||
67 | var emptyBody = mergedBodies([]Body{}) | |
68 | ||
69 | // EmptyBody returns a body with no content. This body can be used as a | |
70 | // placeholder when a body is required but no body content is available. | |
71 | func EmptyBody() Body { | |
72 | return emptyBody | |
73 | } | |
74 | ||
75 | type mergedBodies []Body | |
76 | ||
77 | // Content returns the content produced by applying the given schema to all | |
78 | // of the merged bodies and merging the result. | |
79 | // | |
80 | // Although required attributes _are_ supported, they should be used sparingly | |
81 | // with merged bodies since in this case there is no contextual information | |
82 | // with which to return good diagnostics. Applications working with merged | |
83 | // bodies may wish to mark all attributes as optional and then check for | |
84 | // required attributes afterwards, to produce better diagnostics. | |
85 | func (mb mergedBodies) Content(schema *BodySchema) (*BodyContent, Diagnostics) { | |
86 | // the returned body will always be empty in this case, because mergedContent | |
87 | // will only ever call Content on the child bodies. | |
88 | content, _, diags := mb.mergedContent(schema, false) | |
89 | return content, diags | |
90 | } | |
91 | ||
92 | func (mb mergedBodies) PartialContent(schema *BodySchema) (*BodyContent, Body, Diagnostics) { | |
93 | return mb.mergedContent(schema, true) | |
94 | } | |
95 | ||
96 | func (mb mergedBodies) JustAttributes() (Attributes, Diagnostics) { | |
97 | attrs := make(map[string]*Attribute) | |
98 | var diags Diagnostics | |
99 | ||
100 | for _, body := range mb { | |
101 | thisAttrs, thisDiags := body.JustAttributes() | |
102 | ||
103 | if len(thisDiags) != 0 { | |
104 | diags = append(diags, thisDiags...) | |
105 | } | |
106 | ||
107 | if thisAttrs != nil { | |
108 | for name, attr := range thisAttrs { | |
109 | if existing := attrs[name]; existing != nil { | |
110 | diags = diags.Append(&Diagnostic{ | |
111 | Severity: DiagError, | |
112 | Summary: "Duplicate argument", | |
113 | Detail: fmt.Sprintf( | |
114 | "Argument %q was already set at %s", | |
115 | name, existing.NameRange.String(), | |
116 | ), | |
117 | Subject: &attr.NameRange, | |
118 | }) | |
119 | continue | |
120 | } | |
121 | ||
122 | attrs[name] = attr | |
123 | } | |
124 | } | |
125 | } | |
126 | ||
127 | return attrs, diags | |
128 | } | |
129 | ||
130 | func (mb mergedBodies) MissingItemRange() Range { | |
131 | if len(mb) == 0 { | |
132 | // Nothing useful to return here, so we'll return some garbage. | |
133 | return Range{ | |
134 | Filename: "<empty>", | |
135 | } | |
136 | } | |
137 | ||
138 | // arbitrarily use the first body's missing item range | |
139 | return mb[0].MissingItemRange() | |
140 | } | |
141 | ||
142 | func (mb mergedBodies) mergedContent(schema *BodySchema, partial bool) (*BodyContent, Body, Diagnostics) { | |
143 | // We need to produce a new schema with none of the attributes marked as | |
144 | // required, since _any one_ of our bodies can contribute an attribute value. | |
145 | // We'll separately check that all required attributes are present at | |
146 | // the end. | |
147 | mergedSchema := &BodySchema{ | |
148 | Blocks: schema.Blocks, | |
149 | } | |
150 | for _, attrS := range schema.Attributes { | |
151 | mergedAttrS := attrS | |
152 | mergedAttrS.Required = false | |
153 | mergedSchema.Attributes = append(mergedSchema.Attributes, mergedAttrS) | |
154 | } | |
155 | ||
156 | var mergedLeftovers []Body | |
157 | content := &BodyContent{ | |
158 | Attributes: map[string]*Attribute{}, | |
159 | } | |
160 | ||
161 | var diags Diagnostics | |
162 | for _, body := range mb { | |
163 | var thisContent *BodyContent | |
164 | var thisLeftovers Body | |
165 | var thisDiags Diagnostics | |
166 | ||
167 | if partial { | |
168 | thisContent, thisLeftovers, thisDiags = body.PartialContent(mergedSchema) | |
169 | } else { | |
170 | thisContent, thisDiags = body.Content(mergedSchema) | |
171 | } | |
172 | ||
173 | if thisLeftovers != nil { | |
174 | mergedLeftovers = append(mergedLeftovers, thisLeftovers) | |
175 | } | |
176 | if len(thisDiags) != 0 { | |
177 | diags = append(diags, thisDiags...) | |
178 | } | |
179 | ||
180 | if thisContent.Attributes != nil { | |
181 | for name, attr := range thisContent.Attributes { | |
182 | if existing := content.Attributes[name]; existing != nil { | |
183 | diags = diags.Append(&Diagnostic{ | |
184 | Severity: DiagError, | |
185 | Summary: "Duplicate argument", | |
186 | Detail: fmt.Sprintf( | |
187 | "Argument %q was already set at %s", | |
188 | name, existing.NameRange.String(), | |
189 | ), | |
190 | Subject: &attr.NameRange, | |
191 | }) | |
192 | continue | |
193 | } | |
194 | content.Attributes[name] = attr | |
195 | } | |
196 | } | |
197 | ||
198 | if len(thisContent.Blocks) != 0 { | |
199 | content.Blocks = append(content.Blocks, thisContent.Blocks...) | |
200 | } | |
201 | } | |
202 | ||
203 | // Finally, we check for required attributes. | |
204 | for _, attrS := range schema.Attributes { | |
205 | if !attrS.Required { | |
206 | continue | |
207 | } | |
208 | ||
209 | if content.Attributes[attrS.Name] == nil { | |
210 | // We don't have any context here to produce a good diagnostic, | |
211 | // which is why we warn in the Content docstring to minimize the | |
212 | // use of required attributes on merged bodies. | |
213 | diags = diags.Append(&Diagnostic{ | |
214 | Severity: DiagError, | |
215 | Summary: "Missing required argument", | |
216 | Detail: fmt.Sprintf( | |
217 | "The argument %q is required, but was not set.", | |
218 | attrS.Name, | |
219 | ), | |
220 | }) | |
221 | } | |
222 | } | |
223 | ||
224 | leftoverBody := MergeBodies(mergedLeftovers) | |
225 | return content, leftoverBody, diags | |
226 | } |